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Tuesday, 15 December 2015

Auro 524 - what's the fuss?

Auro has been busy developing a new paint range that has been based on their new binder - REPLEBIN®. This new biogenic binder (made of plant alcohol ester with organic acids) manages to hold the paint together better than any of its forebears. This means that it has excellent abrasion characteristics. The new paint passes the Class 1 high abrasion resistance test.

The binder also helps the paint cover a variety of surfaces. The new 524 is able to cover a wide range of existing types of finish. This means that you may well need one less coat of paint. This can save a lot of time and resources and this leads to a saving in cost. 524 is suited for all indoor surfaces, it adheres to old and new plaster including lime plaster, dry lining boards, previously painted surfaces even on latex (vinyl) paints and other 'difficult' substrates. Note that it is suitable for lime. Most emulsions are not suitable for lime plasters due to the need for the plaster to breathe. With 524 it has an SD value of 0.05, so it is an open pored product.

The use of natural ingredients (in line with Auro's philosophy) means that the paint is low odour and also classed as VOC free. The ingredients are also vegan.

This binder is holding together improved ingredients that create a paint that is very opaque. This is important as it means that it can obliterate variations in the existing wall finishes. This means that even dark or patterned surfaces can be covered white quick and easy: It is classed as a top opacity product with a rating of 99.5 % (Opacity Class 1).

As far as application is concerned the paint dries quicker than its predecessors and can be easily applied by brush, roller or with spraying equipment. It has little to no dripping and splashing, thus making painting more pleasurable.

The paint is more expensive per litre than other natural paints, but it is cheaper than many of the 'designer' paints. So if you are looking for the highest quality paint, with the best environmental credentials then look no further than the 524.

Wednesday, 2 December 2015

New Solid Wall Insulation Guide

Bristol City Council came to the Sustainable Traditional Buildings Alliance (the STBA) to address the issues associated with the Solid Wall Insulation (SWI) works that they were doing. The video and associated tools (that can be found at have been developed to help locals find out about solid wall insulation (SWI) and the issues associated with it.

As you will know we are board members of the STBA and so have a keen understanding of the issues around SWI. So we recommend that anyone thinking about SWI should have a look at the video made for the Bristol as certainly many areas of Wales are in a similar climate / weather pattern to those living over the channel.

Getting the balance right is really, really important and the whole house approach is one that we have been delivering on for many years. With Bristol taking the lead we hope that many councils in Wales will learn from this ground breaking work and adopt a similar approach.

We really need Building Control, Planners as well as Architects and Builders to get onboard with this knowledge and concept. Without their buy-in it is difficult for owners of houses to enact on the best advice. Our focus on energy only is ruining houses and homes and we need to stop, take a breath and really look at each house individually.

Assessing the structure, materials, occupation, context and character of a building is MORE important that just looking at how much energy it is predicted to use (by using inaccurate EPCs). We need to ensure that the integrity of the house is improved by addressing ventilation, material compatibility etc otherwise we will end up damaging the health of the structure and its occupants. That is a waste of resources, money and ultimately will not address the underpinning threat of climate change.

So if you are thinking about refurbishing your home and want an independent assessment of what to do, what the risks are, what materials will minimise impacts on your health etc etc then give us a call at the Eco Home Centre.

Thursday, 19 November 2015

New tool for upcyclers

New Grime Go from Eco Solutions
One of the major issues when undertaking upcycling is making sure that the furniture / object is really nice and clean, ready to take new paint / varnish etc. Getting objects ready can be a smelly, toxic process that is not good for lungs, hands etc. So, thanks to the lovely people at Eco Solutions there is now a safe solution.

Grime Go!, available from ourselves, for a reduced price (as ever!) is easy to use and really effective. So if you are planning some upcycling, or just want to have some of your stuff a really good deep clean then it is worth trying it out.

It works inside and out so you will be able to find a wide range of uses for it.

Tuesday, 3 November 2015

Home Report Video from Profiad Ni

Thought that this might be of interest as it shows the types of advice given when we do a Home Inspection Report. The winners of the Profiad Ni competition had visits from us for around 2 - 3 hours each followed by a written report that re-enforced the messages about damp, energy efficiency, maintenance, ventilation, structure etc.

It was a great couple of days (if a tad tiring) so many thanks to Bethan from Profiad Ni for arranging it all.

Happy watching.

Friday, 2 October 2015

Brick face failure

This is quite common to see bricks suffering from old age (and occasionally poor pointing)
This is the type of wall that is commonly rendered over (using cement) because the bricks have lost their faces and hence are much more prone to the weather.

The rendering over can of course cause many more problems due to old bricks (with lime mortar) not being compatible to modern waterproofed cements. The obvious answer, assuming that you are happy to render over, would be to use a compatible lime render. This will work with the wall to help keep it dry and also provide it with the necessary protection from the elements.

What to do though if you want to save the look of your home?

Well, getting the same bricks to match is difficult and would require lots of research as many of the old bricks were made by small local factories that have now succumbed to nationals and multi-nationals. Getting a colour and texture match is therefore a bit tricky.

The answer, though, is staring us in the face (apols for the pun). Each of the damaged bricks will have a perfectly preserved face on its other side, so all we need to do is to turn it around! Easy (said.)

Removing the mortar can be a bit tricky, but where the original lime mortar is, it should be much easier as the mortar is softer than the brick. Where it has been re-pointed using cement the opposite is true and this causes more problems. The use of lime mortar is important for this very reason. Mortar in old houses was there more to keep the bricks / stone apart rather than to stick them all together. When we started building thin walls (cavity walls are effectively two very thin and unstable walls) we needed to stick them together using strong cement mortars and wall ties.

Anyway, back to the point. How to get them out. Well there are a couple of tools that are generally used: Angle Grinders and also Masonry Plunge Saws. The main issue is minimising dust. Silica dust can be nasty and so make sure that you wear a mask. Personally I think that it is worth hiring a Masonry Saw (also known as Wall Saws).

Wall saw
Basically, you then cut around the brick(s) in question and then you can remove them, flip them around and reset it back into the wall using a matching lime mortar. Good luck!
Brick turning

Friday, 11 September 2015

Killing mould naturally

Mould commonly appears where walls / surfaces are cool and damp

How to treat mould? Well it is commonly assumed that the best way of doing this is using bleach. However, if you do use bleach you will experience several things:
  • The mould will return quite soon (bleach only works on hard surfaces and so will not kill the mould 'roots' in any porous material)
  • It will smell terribly
  • You will have to get out the gloves to protect your hands
  • You will have to be very careful to ensure that you don't bleach anything else
So are there any better and safer alternatives? Thankfully the answer is a resounding YES.

You can buy products like the Auro Anti-Mould System (that we supply) or you can make some mixes yourself.

Systems that actually work and are safe include:
  • Hydrogen Peroxide (this is the main ingredient in the Auro product)
  • Tea Tree Oil
  • Borax
  • Baking Soda
  • Vinegar
  • Grapefruit Seed Extract
The best are those that are not just alkaline (Baking Soda and Vinegar) but also naturally antisceptic, antifungal and antibacterial. So the Hydrogen Peroxide, Borax, Grapefruit Seed and Tea Tree Oil (ensuring that it is from Melaleuca Alternifolia) provide the best solutions. These work on porous surfaces as well and so kill the 'roots' as well as surface mould.
  • Tea Tree Oil use a spray in a 2% solution
  • Hydrogen Peroxide use a spray in 3% solution
  • Borax use a spray in 6-7% solution
  • Grapefruit Seed Extract use a spray in 0.5-1% solution
I would recommend that Hydrogen Peroxide is sprayed on and then left for around 10 mins before being wiped off. The rest can be sprayed and left on to act as a longer term inhibitor.

I would also suggest that you need to deal with the root cause of the mould in the first place. This might be making the surface warmer (potentially by using insulation), making the material drier (by increasing ventilation around the area, using correct materials, eliminating water ingress etc).

Thursday, 10 September 2015

Home Buyer Report - The Journey

This is what the Home Buyer Report (HBR) looks like that you will probably make a lot of decisions by when you buy your new home. One of these will cost you around £450 - £700 depending on the level of investigation requested. Most people opt for the cheaper version.

So what do you get for your money?

The report is designed to look in detail at the condition of the house and make recommendations as to any course of remedial actions required. This is of course important for you to know as there may well be some major issues like subsidence or damp.

The majority of the report is basic tick boxing and space for some additional comments. However, mostly what goes into the comments box is something along the lines of: damp noted in such and such room, we recommend that a damp proof specialist provides a report. Quite often 'rising damp' and 'injected damp proof course' are mentioned. This is odd given that most truly independent damp specialists suggest that only around 5% of damp houses are suffering from 'rising damp'. So why is it put in those specific terms when the rest of the report is otherwise quite generic?

The answer seems to be this all pervasive thought that damp only occurs at ground level and is always caused by rising ground water. This is so common that many houses, that I have been to where a HBR has been shared with me, surveyors have not even tested for damp above the ground floor (unless it is blindingly obvious). It is almost that penetrating damp doesn't exist for some surveyors. I have not seen reference to orientation of the house or exposure levels in any HBR to date.

So, the next step on your house buying journey is to get a damp specialist in. Having spent £450 on a report and found that there is damp, you are starting to have doubts about buying, so having a free report from a damp proofing company seems like a good idea. What little we know.

The reports from a damp proofing company virtual all say - you have rising damp and require a damp proof course (DPC). This will in turn cost you between £3,000 and £6,000. Not so free now is it! Then you haggle over prices, it comes down a couple of thousand if you are lucky and the 'required improvements' to the house come to £2,000 - £4,000 net. Plus you have a guarantee! Sound OK?

Well actually, as you may have picked up, most damp is not rising damp. So the money spent will probably not cure the damp. In fact it can make it worse in the long run. But the guarantee? Unfortunately it is not worth the paper that it is printed on. It is a chocolate teapot. Looks great, makes you feel like you can have a cuppa at anytime, but make one and whoops!

So, be aware that if you do have damp picked up on your HBR, it may just be worth your while employing an INDEPENDENT damp specialist who will not just go through the motions and come to the conclusion that you need an expensive (and ultimately potentially dangerous) (DPC). S/he will look at the whole house holistically, assess the pathology of the building - what has been done, when, how well, using what etc. and should then be able to provide a much better and more appropriate set of recommendations or comments.

This can be fraught with difficulty as most of the time you have to use little physical clues, an eye for detail, years of experience, knowledge of the real world building industry and some imagination. Houses have years of history associated with them. We don't keep records of who did what and when, we don't have pictures of the work being done etc. Experience is key. A qualification is good, but really it is the experience of seeing large numbers of houses, noting common faults, listening to owners and tenants and getting their stories etc that really provides the knowledge to be able to diagnose buildings well. Afterall the only real way of knowing what is actually going on is to take the building apart, so given that this isn't going to happen the best solution is to rely on the experience of a truly independent specialist.

Just to add a bit of paranoia into this (because it is warranted), Estate Agents want to sell you the house. It is their income. They want you to buy the house with blinkers on. 'Lovely location', 'Close to a good school', 'Good transport links' etc. Similarly Surveyors don't want to take the risk of doing a diagnosis as it is frought with unknowns, better to take the money and pass the buck onto a specialist in damp. The average 'Free Survey' damp specialist comes from a company that wants to sell you a damp proof course, .......

Knowledge is power and it is important when making the biggest financial decision for your family that you get it as right as you can. Getting information from a reliable, independent source that will explain what's going on, the physics and material science behind it etc is really important and worth the money.

What is the point in spending £ thousands on a DPC when actually the damp is due to some pointing issue, or a failed window seal, something that might cost you a couple of pounds.

I know that this sounds like a sales pitch as we provide this independent service, but whoever does it, the principles hold true. People like me, who understand damp and materials, will be able to give you a much better, much more detailed idea of the issues that face a house and hence will allow you to make a much better decision.

Friday, 14 August 2015

Rising Damp

From Yorkshire Times article entitled 'Rising Damp in Old Houses - It's just a myth'
I have been to two houses in the past couple of days, both of which have had damp proof courses (DPCs) injected into them. These new DPCs and associated work are now actually causing more damp problems than were there before!

One house has evidence of approximately two injected DPCs and the owner was being recommended to have another one. I bumped into a neighbour who had seen the original plans for the houses in the Glamorgan Archive and guess what, it turns out that it has had a DPC since the day it was built!! 

What are we doing believing damp proof 'specialists' from commercial damp proof companies? Their 'free' surveys might not cost anything, but the recommended treatments that they come up with with see thousands of pounds leave your account. So much for being 'free'.

So in the first house, there was a lot of damp all around the front bay and along the west facing wall. The damp 'specialist' failed to identify that there were a number of large cracks in the render, or that the render on the bay was blown. Neither did he mention anything to do with the lack of ventilation in the house, .......

In the second house, the damp was now appearing over a metre from the ground. No doubt that there was damp in the floor of the house, but sealing up the wall as a cure, really?? That is just trying to hide the damp, not to actually deal with it. Now the owner will have to remove all the hard waterproof render and start again with a proper solution. More expense, disruption and hassle. Why?!

If you are serious about solving a damp problem, rather than causing one we would recommend that you use a good independent damp specialist in older buildings. We could save the 'hard working families' of the UK lots of un-necessary expense and also help to preserve our built heritage rather than introducing ridiculous ineffective modern quick fixes.

For a good rant, have a read of the Yorkshire Times article here

Tuesday, 14 July 2015

Measures working, but still more to do

Last year we spent a lot of time getting the walls of our home sorted. I dug a trench around the house and installed drainage to make sure that rainwater was taken away from the plot as quickly as possible. The walls were also stripped of their cement render and a lovely new render from Welsh Lime Works was applied.

So where are we now?

Out of the red and into the green
Well I went around the house yesterday to check moisture readings in the external walls and I am happy to announce that the levels are down from the mid 20% to around 10-13%.

So the external walls are drying out even now, despite have amount of water that was allowed into them after the cement render was removed and then the application process associated with the lime render. So great news!

However, the internal walls where concrete replacement floors have been installed are still wet. The lower part of the wall, where the waterproof render and plaster has been fitted is around 10%, but above the 1m mark where the original lime plaster is still intact is wet through (mid 20%s). I have been hoping that the silicon treatment that I installed would have had an effect by now, but it seems as if there is still water being sucked up by capillary action between the waterproofed render on the walls.

I think that I will have to inject more silicon cream into the mortar at the base of the walls to see if I can reduce the amount of water being drawn up. The water pressure that is created by replacement floors is amazing, but I have little choice as to the action I can take, bar cutting out the mortar and installing a physical DPC - lots of dust that the rest of the family might not appreciate!

So, good news on the main piece of work on the house, but still a little more to do to remove the issues created by blindly following the conventional damp industry and mortgage providers.

Tuesday, 30 June 2015

I can't afford lime render!

Lime rendering done by Welsh Lime Works in Cardiff
Lime rendering is a specialist trade (not to be confused with lime plastering or cement rendering!) and as such it takes time served craftspeople to do it well and it also takes more time to do. These two factors mean that many people who need to have their houses re-rendered choose the cement route. Using cement, of course, represents a higher long term cost. The render will crack and, most likely, damp will be re-introduced to the walls. This will need to be addressed again in the future, whilst a lime render should last the lifetime of the building.

A customer of ours choose cement render over lime due to the cost, however within 8 months the cement had failed, the wall was still wet and she has had to do it again. So the difference in price has already been negated due to failure.

However, this article is about what to do if you cannot afford at the moment to replace the cement with lime.

My recommendations (in general) would be as follows:
  • Keep the existing cement render on
  • Regularly check the walls for failed render (tapping the walls will audibly indicate where the render has become separated from the wall)
  • Repair any cracks (even the small ones, especially if facing the prevailing winds and rain) and any blown areas of render
  • When replacing blown areas, it is better to cut around the render to be removed so that the process of removal does not dislodge any of the surrounding render
  • Use cement render to replace / repair
  • Check for failure of seals around doors, windows, pipes etc and repair as necessary
  • Save up and when you can afford it, replace the cement with lime.
Enlarging cracks allows for a better repair as the new render will fit into it
The rationale behind this recommendation is that where you have a structure that has been altered to try to keep water out then as long as this philosophy is being maintained then it will have a better chance of working than when it is not. Cement render and masonry paint is designed to keep water out and as long as it is doing this then it will provide some protection from wind driven rain, however it needs to be uncompromised. So maintenance of its integrity is really important. The more water that gets behind it, the worse the wall will perform and the more likely damp issues become.

This patching and maintaining is really important to allow the wall to perform as well as it can before the ultimate solution of the lime render is applied. So don't waste your money on putting a new coat of cement render over your pre 1919 solid wall house, repair what you have and save your money up so that you don't waste it on an unsustainable, and still quite expensive, piece of cement based sticking plaster!

If you have a 'rising damp' problem (this is rare to occur in most untreated houses, but can be caused by the introduction of cement based renders and plasters onto a breathable wall) then another cheaper option is to remove the cement render up to around 1m above ground level. This wall might then need to be repaired using lime mortar (re-pointing) or it could be lime rendered. Doing this at ground level means that there is no need for scaffolding and the area involved is much less, thus keeping the costs down. You will need a good drip above this so that any water running down the upper wall is not fed directly into the lime or onto the exposed wall.

If you need to put up expensive scaffolding to do the repairs then this brings an extra dimension as the lime rendering becomes more cost effective in the longer term. So any initial repairs to the cement are best done off of a tower scaffold or ladders.

I have written at length before about lime rendering, but it is worth re-iterating at this point the things to remember when looking for a good lime renderer.
  • Use a company that both supplies and installs the render (this can get over the issue of where, if there is a problem with the final work, you are not inbetween a rock and a hard place where the installer blames the manufacturer and the manufacturer blames the installer!)
  • Remember that rendering is not the same as plastering. So use an experienced renderer.
  • Ask for references and a good portfolio of completed works
  • If it is new company then you will need to ask about the experience of the tradespeople and where they served their time. You can then investigate this company.
  • Read up about lime from trusted sources like CADW, Historic England, Historic Scotland etc (depending on where you are)
  • Ask about the mix that they will use and the finish that will be applied. I am a believer in aggregate being really important. I think that the aggregate needs to be a mix of sizes and also that it contains a high proportion of permeable stone.
  • The finish needs to be appropriate. So a lime putty and permeable stone mix can be easily covered with a lime wash, a less breathable combination of NHL lime and sand will probably work better with a mineral paint.

Friday, 19 June 2015

Energy Efficiency Consultation - A Welsh response

Welsh Government is consulting at the moment with the wider public about energy efficiency and their new strategy. Thankfully we now have the Future Generations Act and this means that we should NOT go blindly down the usual roots of using rubbish drivers like rdSAP, U values calculators etc. In Wales we MUST take into account issues like Health, Prosperity, Economic Development, Our Place in the Wider World etc.

So we stand a chance of getting it right (or at least better than we have for the past decade or so). The consultation document is available from the Welsh Government website (direct link given, or reference WG25502) or use this web address:

My comments are driven by the latest research that has been made available to DECC to organisations like BRE (Buildings Research Establishment), STBA (Sustainable Traditional Buildings Alliance), UCL (University College London). So Government and DECC know the issues around EPCs, rdSAP, Green Deal, Thermal Bridging, U value calculators etc. BRE already have demonstrated 126 unintended consequences associated with 'improvements' to solid walls!

However, it is a huge political issue as so much has been invested in these inaccurate and potentially dangerous tools. Welsh Government can choose (to a certain extent) to be BETTER than the UK Gov and really lead the way to a more sustainable future, but it will take courage. However there are lots of long term benefits to putting Wales at the vanguard of the energy efficient / sustainable building world.

As far as the consultation document is concerned my thoughts are:

5.1 Overcoming Barriers
1.1 Improved Information
- We think that giving people really good advice is important, however it needs to be based on RISK and a good understanding of the actual house / life style. This requires trained people who understand building types, building pathology, the limitations of EPCs, moisture, etc.
1.2 Work with others to encourage energy efficiency
- Again this is fine as long as those people have the time / knowledge to give really good individualised advice that highlights risk and takes into account individual circumstances
1.4 Providing Free Energy Efficiency Assessments to Low Income Families
- The EPC tools used are not reliable for many house types in Wales and certainly gives generic advice that needs interpretation. Luring people in with unrealistic savings and also high risk measures will just create situations where the poorest might be done a serious mis-service.
1.5 Continue to provide advice
- The NEST service is again driven by the unreliable EPC system and so needs to be adapted. It should also look at the wider issue of health, Internal Air Quality (IAQ) etc.
1.6 Making Energy Efficiency easier for people
- We must start with the fact that many energy efficiency measures are NOT easy. We need to give people confidence by providing good and rounded advice that highlights risk and how to minimise them. Honesty is the best policy here.
1.7 Ensuring that the PRS (Private Rented Sector) meet their obligations
- Again we are using EPCs that give advice that is poor, inaccurate and will encourage the cheapest and easiest roots to a E rating. Some improvements that give E's will be detrimental to health of occupants and also not deliver the actual savings. We need to be smarter and to ensure that appropriate guidance is given to minimise this risk. This means appropriate recommendations need to be given. At present the EPC guidance does not give 'clever' advice and this is misleading.
1.8 Review Part L of Building Regulations
- Again we need to ensure that we give lower risk advice / guidance. Pre 1919 buildings need to have better data and we need to consider issues like reverse condensation, maintaining breathable walls, moisture levels etc. We also need to link in Ventilation into the advice to minimise risk to these older properties. The use of EPCs should also be re-assessed and the issues surrounding detailing / thermal bridging etc.
1.9 Drive achievement of the WHQS
- Given the costs associated with continual upgrades should each property be assessed in a manner that makes it as good as it can be (with due diligence to health of the occupants, building structure etc). This might mean that one building at SAP 60, whilst others achieve 85! Having a purely arbitrary level of 65 might cause a lot of problems that will ultimately cost more and also not give the results expected.
1.10 Align community based activity
- Communities need to give accurate advice and this can only be achieved by understanding houses. Whilst people can help drive interest we should rely on trained specialists using the right tools to give the actual individualised advice
1.11 Provide advice to businesses etc
- Each property is different and so using showcases can encourage uptake, but each property needs to be assessed individually and so care is needed not to promote solutions that are not appropriate to all buildings.
1.12 Integrate support into wider business advice
- Fine, but it needs to be good advice and support
1.13 Work with large businesses
We need to look at how we can use large industrial waste heat can be used for community benefit. District heating schemes, linking heat exporters with importers etc. Planning needs to be involved and encouraged to think strategically.
1.15 Increased support via Green Growth Wales
- Support needs to build on a strategic approach to support relevant industries that provide low risk solutions to energy efficiency etc. Wood fibre should be a standard specification product for many Welsh houses and it needs to have the backing of WG  and GGW in order to find its market.
1.16 Advice in public sector
- We need to give low risk advice that is tailored to each building
1.18 Drive efficient use of public purse
- As 1.15 we need to ensure that we develop industries that provide us with low risk solutions

5.2 Supply Chain Development
2.1 Support for installers to diversify etc.
- All installers MUST have training in Underpinning Knowledge of buildings. Recognising building types, understanding how they worker, common maintenance problems, the effects that changes / improvements might have. They must also be able to justify and decisions and the rationale that underpins it.
2.2 Strengthen support for supply chain development
- Again we need to have correct specification based on a more holistic approach, for example health considerations as well as energy efficiency. This means development / use of different materials / products that are currently used. Training and robust detailing driven by Government needs to used to drive this development.
2.3 Support supply chain through WG programmes
- This is key and needs to be driven by RISK assessment (via STBA work) and a HOLISTIC stance that covers FGA requirements. So addressing moisture, Internal Air Quality etc needs to be a WG specification criteria and then this is backed up by contracts that encourage adoption and hence provide a market for newer, better, natural and local products.
2.4 Quality of delivery
- On paper PAS2030 and other warranties offer protection, but in the real world they are either not tested legally, or are pretty worthless due to the complexities of building physics. So we must use RISK assessment rather than reliance on worthless paper comfort blankets. We must address the lack of underpinning knowledge in the construction industry. Builders MUST understand basic building physics, material compatibility issues, common 'improvement' issues etc. Ideally any builder working should have a minimum qualification to be able to do the work and anything done on a solid wall building needs to have additional modules completed and passed.
2.5 Entrepreneurship
- In order to get the right products made we need entrepreneurs to lead on this, BUT they do need to have the support from the specification teams in WG, Local Councils, Housing Associations in order to free up investment monies.

5.3 Skills and Education
3.1 Skills that respond to local need
- In Wales we have the oldest building stock in the whole world. We need to develop specialist skills to work on our older properties. We need to understand them, to know how they were made, how they have been changed over time, what materials have been used, how these materials inter-relate, how we live in buildings and how this has changed building physics. We MUST become specialists in sustainable retrofit. This means upskilling the existing workforce and also ensuring that the new trainees are filled with underpinning knowledge.
- We also want to have the lowest carbon new builds and so again we need to have people trained in concepts like Bio Solar Haus, Passive House, Ty Ynnos etc. They also need hands-on training in practical applications like airtightness, ventilation etc.
3.2 Mainstream provision of skills
- All builders should have the relevant qualification for the work that they do. Pre 1919 houses need specialist knowledge and skills, System Built houses again need different skill sets. At present anyone can call themselves a builder and do work, we need to have better control over who does what to our housing stock.
- All school children should have modules that cover houses. People need to understand their homes and where things are for a whole range of reasons. Secondary schools and Primary can start to address this relatively easily through ESDGC.
3.3 Post 16 training and education
The vast majority of the construction industry is based around new build. We need to ensure that we cover maintenance, building history, materials etc as well as underpinning knowledge on building physics in all courses.
3.4 Enhanced employer engagement
- One of the things that is really difficult to manage is that old habits die hard and so many in business today will only pass on old thinking and old ways of doing things. This is fine on modern buildings, but on older properties it is dangerous and high risk. So again we need to manage employers so that they are appropriately qualified for pre 1919 work if they are taking on apprenticeships.
3.5 Business capability
- CITB have developed new Upskilling courses for pre 1919 energy efficiency work that should be adopted by WG to help ensure that 'new' knowledge is widely understood and used.
3.6 Capital Investment in 21st Century Schools
- Schools must also work cover health, safety, noise, adequate space, ease of use etc as well as energy.

5.4 Innovation
4.1 Support new products and services
- We can all benefit from using new techniques like Bio Solar House and Passive House, but we can make these Welsh as well by using our national natural resources. This should be a priority. Having new zero carbon Welsh Vernacular is one way forward.
- All new products should be designed to further the aims of FGA rather than just energy efficiency.
- Major new products (like wood fibre insulation) must be supported by specifications in contracts from WG and other public sector bodies.
4.3 Energy efficiency in public sector
- The current research needs to inform this, so that we encourage products that fulfill all FGA criteria. Products that are encouraged need to be healthy, low carbon, local etc.
4.4 Smart Living demonstrations
- These should be used to help inform people about their houses and how to manage risk.
4.5 Shared Learning
- Always important, but context is important.
4.6 Innovation on WG programmes
- WG needs to be wise in its work to ensure that it is appropriate, low risk etc and also encourages the right type of innovation. We can be a UK leader here and show how smart we can be by not storing up problems for the future.

5.5 Finance
5.1 Information of financial support for householder
- This is fine, but we need to make sure that the right type of support is available. No point taking up grants to undertake EWI where it is not appropriate.
5.2 WG Investment
- rdSAP and other tools push us in the wrong direction for older buildings and so we MUST be better than the tools that we use. We made them, we can change / adapt them to make them better suited for use. We must not be driven by funding, but have the strength of character to say what we want / need and then for the money to follow that.
5.3 Loan funding
- Any funding MUST be linked to a risk assessment based on best practice. Loans must have low risk works associated with them so that people are not faced with long term maintenance etc associated with poor initial specification.
- We must use the best techniques / skills / materials etc to bring houses back into being homes. No point doing unsustainable face lifts.
5.4 Leverage
- Funds that allow us to work sustainably on our buildings should be used. If it is not right for Wales, then don't use it. Mistakes can take a long time to materialise and then who will pick up the bills?
5.6 - 5.8 Finance for business
- We must get specification etc right to minimise long term costs
5.10 Energy Performance Contracts
- EPC's are NOT fit for use on 1/3 of our stock. rdSAP and SBEM are NOT good tools. DECC, BRE, STBA and many other know this. WG has been told. EPCs are dangerous and MUST not be used in isolation. Pre 1919 buildings are most notably at risk. I cannot stress this enough. We should be using other tools in partnership with EPCs and we must have assessment criteria that take into account IAQ, Moisture content, health, noise etc.

Impact Assessment

Where is the Health Impact Assessment???

The major impact of the strategy at the moment is to put a third of all houses and their occupants in Wales at risk!

The key risks are:

  • Creation of major thermal bridges in houses (environment & economic)
  • Creation of conditions for damp and mould in houses (environment, health & economic)
  • Structural damage due to water ingress (environment & economic)
  • Trapping moisture behind External Wall Insulation (environment & economic)
  • Creation of chronic health problems esp. respiratory illnesses (health & economic)
  • Not getting the savings / carbon saving that are projected (economic)
  • Long term maintenance costs (environment & economic)
  • Costly insurance claims or high costs for owners in stripping out / off 'improvements' (environment & economic)
  • Wales losing it's character buildings and part of its identity (environment & culture)
  • No major economic change as work will go to larger companies (economic)
  • No economic advantage by having a more informed workforce (education & economic)
  • No new innovative industries that put Wales ahead of the curve (economic)

There are more ....

Other issues

There are a wide range of topics / issues that fall out of this. We MUST have a new modus operandi and this is a key document to change this. Our built environment is AT RISK thanks to the blinkered race for energy efficiency, we MUST look holistically both for the sake of the FGA, but also for the future of our built environment.

Tools like rdSAP need to work in conjunction with MOISTURE tools. Moisture tools also need to be based on REAL WORLD situations not the current tests that actually state that they are not fit for purpose for 'in service' conditions. STBA (& soon BRE) work for DECC on solid walls demonstrates that we are storing up problems by using inappropriate test regimes for moisture / damp.

Health NEEDS to be part of this. We spend so much time indoors we need to ensure that the internal environment is as good as it can be, both for the inhabitants and the building structure. We need to measure and value IAQ, moisture levels, humidity and noise if we are to have sustainable buildings.

Wales MUST opt for low risk solutions in the immediate future and this might be focused on things like renewable energy generation solutions rather than energy efficiency. This might be seen as tackling the wrong end of the energy pyramid (and that would be correct), however we must focus on risk, as it is very easy to get it wrong especially when we have an ill informed construction industry and populace. We need to address education / training / awareness first so that we get it right. So initially focusing on low risk activities allows us to work whilst also getting prepared for the more complex structural works.

Friday, 12 June 2015

What constitutes a 'healthy' home?

Health is really important to all of us, yet many of us live in houses with poor internal environments. Some of this is our own fault - we clean using dangerous chemicals; we allow properties to get into a poor state and hence introduce damp from rain; we don't ventilate properly; etc. However, some of it down to the structure of the building. So I thought that it might be worth investigating the idea that using health as opposed to pure energy efficiency could be a way forward for improvements in the housing sector.

So what are the key health factors that could be used to drive new specifications for home improvements?


People seem to be getting more sensitive to substances, many of which are airborne. So there is a need for better Internal Air Quality (IAQ) in our homes. Having filters in ventilation systems is an obvious way of improving the situation for cleaning any air coming into our homes, however most properties do not have whole house ventilation systems, but there is a trend towards positive pressure ventilation in retrofits. These units can have filters fitted, but it does mean that they have to be cleaned / maintained on a regular basis and so this means that we have to have a system in place to ensure that this actually happens (otherwise it is waste of money and resources).

Many materials continue to off gas substances throughout their lives, so it usually better to use natural materials that have been treated with natural preservatives / protecting coats.

The main source of allergies, though comes through from our foods and the effects of our lifestyle choices. This could be the type of cleaning materials that we use, whether we smoke in the house etc.

However we can reduce dust circulation by using radiant wall heating rather than conventional radiators or underfloor heating.

Respiratory diseases

Respiratory problems are caused by a range of root causes many of which can be tackled during refurbishment. Issues like high / low humidity, mould and dust can all be effected by what we do to our homes.

It is really important that we manage ventilation in our homes as this helps to control humidity, but it is equally important that we allow any breathing walls to continue to do so. Sealing up older 'moist' walls can introduce damp and hence mould etc. Having a relative humidity of between 50 and 60 per cent minimises the risks associated with dust mites etc and this range can be maintained by the use breathable solid walls. We must also be careful when installing insulation, as poor fitting / specification can introduce cold spots and this in turn can easily create damp / mould issues.

Automatic ventilation control systems that run off information like relative humidity and CO2 levels can really assist with maintaining a good internal air quality. These can be installed where there is a good airtightness in the building and ideally systems would also have heat recovery built in.

Temperature related troubles

Overheating and underheating can cause or exacerbate serious medical conditions, so again we must ensure that properties do not get too hot, or too cold. So design is really important to make sure that properties can cope with the projected changes in climate which suggest that our weather will get more extreme in the future, especially with hot conditions. Unless of course the Atlantic Conveyor gives in and we might then become much, much colder in the winter.

So must ensure that properties are designed for both. Using high thermal capacity insulations like woodfibre boards and batts can assist with this. Being able to create homes that can easily and cheaply maintain a comfortable 19 degrees C in both summer and winter is important.

Highly efficient heating systems need to be used that are appropriate for the type of house, so care is required to specify the best type of system. Some houses only served by oil and electricity, others gas etc, so the most efficient systems need to be specified and this might involve additional works. For example ground source heat pumps (GSHP) only work well at low temperatures and so a well insulated house with managed ventilation is required here. A very efficient GSHP in a poorly insulated and draughty home will be very inefficient.

Mental health

Now this is a real bag of worms. Issues like stress can come from a wide range of factors that can be designed out (or into) our buildings. Common factors that effect stress at home include:

Money worries - making our homes cheap to run is really important (as long as we don't cause lots of 'unintended consequences' at the same time). So installing systems that improve energy efficiency, reduce water consumption, minimise maintenance costs, prolong maintenance intervals etc. is really important. Renewable energy systems that attract support can also help to relieve financial pressures by providing some free energy, but also a small income. However, it should be remembered that people make choices when it comes to spending their money and it may be that the best ones are not always taken.

Families - families don't always get along and having separate spaces can be useful. Knocking through reception rooms to make large spaces may not be the best solution. Sound proofing between rooms is also important to create more private space. Having bedrooms that are acoustically isolated can make sleep better and this can be really important.

Neighbours - again neighbours can be a source of comfort or stress. Whichever it is, having good acoustic barriers between the two houses is important. It is also important that any thermal improvements to one house do not cause problems with any adjoining property. So care needs to be taken here.

Natural light - a lack of natural light effects many people, especially those suffering from SAD and so it is important to ensure that light is maximised. This might mean using sun tubes, roof windows etc.

Worries about safety and security - using good quality doors, windows and fixings, combined with clever design can create homes that both feel, and are, more secure. 

Alleviation of niggles - of course there are no end of these, but some are avoidable: Alleviating pressure drops in hot water when more than two outlets are being used; use of long life bulbs to reduce need for replacement; easy access to water stop-cocks if there is a major leak; isolation valves on water outlets for easy routine maintenance; use of siphon toilets rather than valve to stop constant leaks; use of metal rainwater goods to reduce water damage from leaking or damaged plastic ones; use of breathable paints on breathable walls to reduce re-painting requirements; no drylining allowed to reduce issues associated with just hiding problems etc etc.


When we start to think about our homes in more detail one realises that we need homes that feature:
  • Good, well controlled, ventilation (e.g using CO2 and RH controls)
  • Appropriately insulated both against heat loss but also heat gain (e.g  use of wood fibre insulation)
  • Minimised the use of water (e.g pulse shower heads, variable siphon flushes etc.)
  • Take advantage of any appropriate renewable energy generation potential (e.g FiT and RHI measures)
  • Minimised use of energy (e.g LED lights)
  • Have good acoustic insulation both between houses and within them (especially bedrooms)
  • Have a mix of private and public space 
  • Have sufficient natural light (e.g using sun tubes etc.)
  • Are free from risk of damp and mould (using correct breathable materials)
  • Use natural materials that are less likely to off gas toxic substances (e.g wood)
  • Use materials cleverly to minimise maintenance requirements (check compatibility of materials)
  • Use good quality materials that provide long term solutions to safety and security (good quality doors, windows and locks)
Now all of that is a tad more involved than indiscriminately slapping on EPS external wall insulation and changing a boiler, however if we start to think more about maintaining a good, healthy internal environment then maybe we can reduce costs on the health service as well as providing better housing for the great British public.

The British Thoractic Society estimates overall costs to the country of £6.6 billion due to respiratory disease (or which Gov. says £1 billion is spent annually by the NHS on chronic obstructive Pulmonary Diseases)

So improving our homes will not eradicate these costs, but it will have some effect. So we can either look to continue doing 'improvements' that only tackle a small fraction of the issues facing our stock (and even this we are doing badly in many cases - and this causes more stress and more long term financial costs to the country) or we can start to create a nation of healthy homes.

Wednesday, 10 June 2015

Forget Energy Efficiency think Health!

Readers of this blog will know my views on lots of the energy driven 'improvements' that we are blindly doing in the UK at the moment.

We are making so many mistakes due to the fact that we are using more than useless techniques, materials etc in a slap dash manner. All of this is being done with the best intentions, but we are storing up many problems for the future by our haste and lack of underpinning knowledge.

In years to come we shall look back at this period in our history and hang our heads in shame, I think that in the worse case scenarios it will be regarded as a modern day 'asbestos' story.

So how can we change and do this better?

Well, a very easy way would be to think about it all in a very different manner.

At the moment all we can think about is energy bills, carbon reduction, fuel poverty and regeneration. None of these things are bad, but they do drive us into solutions that are not fit for purpose. For any readers not up to speed here there are fundamental flaws with how we measure energy efficiency in buildings (especially older ones), how we measure thermal efficiency in walls and also more importantly how awful we are when it comes to moisture. Have a look at the STBA reports on thermal and moisture measuring for more info.

Now DECC know all of this stuff - the STBA have told them, but it takes a long time to change Standards, Conventions, a whole industry! And then there is the political fallout! So basically we will have to wait a long time before we manage to make things better, so in the meantime we shall continue to make lots of mistakes and install lots of inappropriate measures.

So, as a proposal, should we not think about Health.

To have a healthy internal environment we need to provide:

  • Fresh clean air
  • Stable Relative Humidity (around 50-60%)
  • No mould or damp
  • Comfortable internal temperatures that are not prone to overheating
  • Sufficient natural light
  • Low toxicity in materials
  • No off-gassing from materials
  • A long term solution that maintains these conditions

To do this we need to have items like:

  • Breathable walls (where they were designed to breathe)
  • Insulation that is suitable
  • Good ventilation that is controlled by Internal Air Quality systems
  • Natural materials used
  • Low / Non toxic materials used
  • Good quality installers / builders

So the basic idea is that, if we can create safe, comfortable and healthy internal environments then energy efficiency comes as a by-product of this process / specification. So we would create good internal environments that are suitable for human beings. Isn't this the point of a building in the first place - to create a safe, sheltered and nice place to spend time with loved ones?

Won't it be great to look at a building and think 'how can I make this a really great place to live?' The satisfaction in making a house a home that you would want to live in and enjoy. After all someone has to live there and shouldn't we make it as healthy, homely and safe as possible?

However if we work within our current unrealistically blinkered parameters we shall just produce internal environments that help to burden the NHS and also provide people with poor quality of domestic life.

So lets start to put people first and I wouldn't mind betting that we shall be able to not only provide high quality space, but also save more money in the long term and reduce CO2.

Wales is in an ideal place to make this happen, but we need to drop using dangerous tools like rdSAP and also BS5250, especially for older buildings.

Tuesday, 9 June 2015

The importance of preparation for wood floors

Preparing floors can be time consuming and dusty task
Wooden floors are glorious things. They have beautiful feel that shows the history of the wood used and reflect the wonders of their individual growth and characteristics. However, if you are using a treatment (like the wonderful Osmo Polyx Oil) it is really important to get a consistent finish on the floor first. A typical application requires a final sand of around 120 grit.

If you don't get a consistent finish then the oil will not be absorbed evenly and this can lead to a number of problems. Recently a customer used new timber on their floor that had not been sanded over after laying. The timber had been put through a planer that had created different finishes on the planks. In some areas the timber had effectively been polished by the planer and in other areas the timber was still quite rough. The new Raw Polyx Oil was then applied.

The Raw product has a minimal amount of white pigment in it to counteract the honey effect associated with oil treatment. It is also designed to have no visible finish, thus making the wood appear to be untreated - raw, if you like.

What happened was that the rough areas allowed the product to 'pool'. This has led to these areas appearing to be milky as the pigment was concentrated in here. Also the polished areas retained their polished appearance as the oil could not be easily absorbed into the wood in these areas. The outcome has been a patchy mix of sheens and colours. Obviously not ideal on a lovely new oak floor.

So it is really important to ensure that the floor has been sanded consistently across the whole surface. Any product will then be absorbed into the timber in a regular manner and hence give an excellent and predictable finish. This is really important where you have a pigment / colour involved in the process.

So time spent in getting this right will bring rewards in the longer term, so build in the time and expense into your equations to allow for good preparation when renovating or installing a new wooden floor.

Monday, 18 May 2015

Getting solid walls to meet Building Regs

Building Regulations in the UK have been interpreted for years as demanding that refurbished walls need to meet a U value of 0.3. Products have therefore been designed using BR443 and BS5250:2011 to comply with this.

Unfortunately, BS5250:2011 states that it is no good at modelling 'in service' situations. The whole model is based on water vapour only, no account for liquid water at all. Not so good when you are dealing with moist walls (AKA virtually all walls built before 1919!)

BR443 is the calculation matrix that gives us U values. This, though, has been shown in virtually all cases to be very inaccurate when assessing solid walls. Caroline Rye's work has clearly shown wide discrepancies with measured in-situ U values with predicted ones from common U value calculators. DECC is taking this very seriously and the STBA has been affecting Government thinking thanks to this key research.

So, given that the tools that we have to use to calculate solid wall U values are, in effect, useless and that the unintended consequences of using non-breathable insulation materials can be as severe as structural failure, what can we do?

Well there is a little used get-out clause in Part L1B of the Building Regulations.

Part L1B states:
Dwellings Exempt from Energy Efficiency Requirements
3.8 Historic and traditional buildings where special considerations may apply
c. buildings of traditional construction with permeable fabric that both absorbs and readily allows the evaporation of moisture

It goes on to say that you should aim to improve the energy efficiency as far as is reasonably practicable and it should not increase the long term risk to the building fabric. It also states that you should make provisions to enable the fabric of the building to 'breathe' to control moisture and reduce the decay problems.

The document also points you towards your local conservation officer for advice. So I would recommend sending them the STBA report on Responsible Retrofit first!

Dr Jo Hoppers work on thermal insulation seems to suggest that the thermal bridging associated with wall insulation is such that even the best detailed Passive House refurbishments will be hard pressed to reach U values much below 0.3, so standard installations will be virtually impossible to achieve these types of figures.

However, within this doom and gloom is there a ray of hope?


The U value research by a growing number of people and orgs (inc BRE) show that the U value of these old solid walls are radically better than predicted, so you might already have a well performing wall! The U value of your wall might correspond to the types tested by the STBA / SPAB by Dr Rye, so it is worth checking your wall structure against the research findings. You can then use this to show your Conservation Officer as well.

Using breathable insulations like wood fibre on walls is a lower risk option, but all this depends on the existing wall structure, how it has been altered over time, etc etc. So managing risk is difficult, but certainly using materials that have been assessed and labelled using inappropriate tests raises the chances of 'unintended consequences'. This subject is one that BRE has been looking at for years and will soon publish its research into.

This post was originally published in 2013, but this is an updated version.

Friday, 15 May 2015

The importance of a good overhang!

In Wales we have had a tendency to design our houses with the minimal amount of overhang on the roof. The tiles sit very close to the walls. This has meant that anything else that we add to the depth of the walls loses precious protection for the wall plate. So rendering and over cladding often has the unintended consequence of making the inner wall more liable to water ingress. Where the over cladding is water proof this can easily trap wind driven rain / overflow from blocked guttering into the structure.

I was in a house last week where the fascias have been twisted and are now potentially channelling water into the building. Another building around the corner from the centre is also suffering after the owners installed external wall insulation. Here the builders had put one of those awful plastic covers over the top of the insulation to 'provide protection' against rain. Surprise, surprise a few months later they were back extending the roof to do the job properly! Wind and rain are a potent force in Wales!

The junction between roof and wall is one of the weakest in a house and so we must be very strict about how we protect walls from the elements. Extending the roof line may seem like a costly addition to any work on the external walls, but if you are doing work on them it may actually save you money if you get it done at the same time. Certainly it would have saved the people around the corner a pretty packet on their scaffolding costs!

If you look at houses on the continent, most have large roof overhangs. This helps to protect the building fabric, provides shading against the summer sun (and with climate change we might even get some of this at some point!), gives additional shelter for windows etc. Learning a lesson or two from the near continent is always a good idea.

Note: this post was first published in 2013. Check through our whole blog for other interesting articles.

Friday, 8 May 2015

Vapour Control Layers in Insulation

The pressure for energy saving in solid walled buildings is real and tangible. Green Deal and rising energy bills are encouraging us to insulate our walls. Where we have external features / facades that we want to keep we are forced to choose internal wall insulation (IWI).

BS5250 (the British Standard) for moisture control in buildings recommends a series of potential interventions (but crucially it also says that this is NOT a recommendation for breathable walls - which are virtually all the solid walls). One of the main recommendations (and hence common practice) is to install a Vapour Control Layer on the warm side of the insulation.

If there is no water in the wall then this works fine, but it is now becoming common knowledge that virtually all the UK's solid walls must be seen as 'moist'.

This is starting to create problems for the vast majority of the solid walls fitted with VCLs or non-breathable insulations due to Reverse Condensation (or Summer Condensation). This is a phenomenon that occurs when external temperatures and hence humidity levels are greater than the internal environment. Higher external pressures associated with temperatures forces this moisture laden air into the wall and when it cools and hits a water proof membrane or insulation the vapour condenses and runs down the back of the barrier. This concentration of moisture deep into the wall structure also means that joists and other wood is more at risk of damage.

The answer is to carefully read BS5250 and listen to what it says, which is, for breathable walls take professional advice from specialists. The best to provide this are bodies like National Trust, CADW, English Heritage and Historic Scotland. Thankfully all these sources of specialist advice are members of the STBA (as indeed RDE is) and their advice / case studies etc are available from

The best advice recommends using a fully breathable insulation (wood fibre for example) with a lime / clay plaster and a breathable paint finish (like our Earthborn Claypaints or Auro Lime Paint). 

So beware of advice and common working practices that are based on half-true information. 

Thursday, 23 April 2015

Cabling and pipes into walls

Walls tend to have a lot of 'punctures' through them
In the UK we build walls and then make holes in them. This is a bit strange when you think about it, but in older houses we are forced to drill through walls in order to install our modern conveniences and technology. So old houses have a range of holes for soil pipes, TV aerials, washing machine drains, phone lines etc. We have also drilling into walls to inject cavity wall insulation, chemical DPCs etc. Take a look at your house and see how many times it has been drilled through.

Surely drilling and placing a cable / pipe through is a simple matter with few risks?!

Oh how wrong we can be. Having just been to a house where incorrectly installed cables and pipes are potentially causing a lot of damp (even on the cavity wall extension).

So where does it go wrong?

Well the most obvious problem is where we encourage water to track into the wall by:

1. Drilling down at an angle rather than horizontally / slightly angled up. A downward slope encourages water to run into the hole especially if it is not properly sealed.

2. It is almost impossible to adequately seal holes / around pipes etc. Most of the time contractors don't even bother trying to seal around holes.

3. Cabling is not looped around so that all cabling enters from below (if cabling goes down the wall and straight into the hole, water will track down it and into the structure).

4. Many holes are drilled into walls that face the prevailing wind rather than exploring another less risky option of an East or North facing wall. This means that the weak spot of the hole is exposed to the worse of the weather.

Sometimes it is difficult to access the best place on the wall for a hole and this is especially the case with Damp Proof Course injections. These tend to be fitted on the external face of the wall and need to be as close to the ground level as possible (generally). This often means that the drill holes are sloping down into the wall due to the body of the drill being next to the ground. The trouble with this is that rainwater running down walls will enter these holes and put water above the DPC! It is vital therefore that these holes are sealed completely and in a long lasting manner, However, more often than not I see holes unfilled, ill fitting plastic plugs pressed in or a dot of mortar placed roughly over the hole. In the long term these will all let water into the structure and cause damp.

So when faced with having to drill through a wall, remember:
  • Keep the drill level (or sloping up slightly)
  • Seal around the cable / pipe using a good quality sealer and press into the wall as much as possible
  • Ensure that the cabling does not encourage water into the wall
  • Put as much cabling through the lee side of a building (rather than facing the prevailing winds)

Wednesday, 22 April 2015

Shoe missing in street

This could be titled: 'How to get a roof load of water into your floors and walls'.

Note the crack between the wall and the pavement
This is a very common sight in urban areas. Downpipes have had their shoes kicked off / removed and so all the water from the roof is being poured into the base of the wall rather than angled off into the main road drain.

In this particular location there was a large gap between the council's pavement and the wall. This has meant that for years the wall have been subjected to way more rainwater than it can cope with. No wonder there was damp in the wall inside.

The simple solution is to re-fit the shoe and get the system back working again. There will still be runoff entering the gap, but at least the volumes might decrease to a level where the wall can cope again.

Oh, for those who were wondering a 'shoe' is as follows:

Wednesday, 1 April 2015

How much insulation is it best to use on solid walls?

Wood fibre board insulation being used externally
Many of you will be aware that I am slightly reticent in recommending certain insulation types on older buildings. This is because of the risks associated with damp, thermal bridging and structural failure. So assuming that you are planning on using a breathable insulation (like wood fibre), how much should you apply?

The Part L of the Building Regulations wishes any refurbishment to get to around 0.3 - 0.35 U value for a solid wall. It thinks that all solid walls have a starting value of around 2.1 which is actually normally much worse that they are. This has led to companies putting on around 120mm thick insulation. Knowing the starting point of your wall is really important as thick walls can be as low as 0.8, so around three times better than predicted. In Wales most solid walls are around 300mm thick and these have an average of 1.51 (from Caroline Rye). So around 30% better than predicted.

In order to get Building Control approval for anything more than 0.3 then you will need to cite that this is a breathable wall and hence special considerations are available for it.

The recommendations I would give change depending on whether you are applying External or Internal Wall Insulation. The base reason also changes.

External Wall Insulation (EWI)

The situation with EWI is that whichever material you choose the real key is to get thermal bridging and rain protection sorted. Reveals, roofs, rainwater systems, etc are all really important to get right. It can be more effective to put 20mm over all the surfaces (inc reveals) than it is to put 100mm just over the walls (not in the reveals). So it is key to get the specification and detailing right.

The more insulation you put on, the less effective the insulation becomes in relation to its thickness. This means that the first cm of insulation reduces heat loss the most, the second will provide less heat loss, the third less still. So there is a rule of diminishing returns at play at here. So there is no point putting on loads of insulation when you will get a similar return from less. As a rule of thumb here to get down to 0.3 you will need 100mm of insulation, However, this assumes that you are starting with a U value of around 2.1. So if your wall is 1.51 then you should be able to use a 80mm board, but remember to put on the 20mm reveal boards!

Even with a breathable system you will need to ensure that it is weathertight. So make sure that the required work is done to rooflines, eaves, guttering etc. 

Any EWI needs to have a protective covering and again this needs to be breathable and also long lasting and so we would recommend a lime render combined with a lime proof mesh and a breathable paint finish (silicate paints are ideal for this).

Internal Wall Insulation (IWI)

Wood fibre board installed internally (from Inglehome)
IWI has the consequence of making the outer side of the wall colder and this can lead to a number of problems including damage from freeze / thaw. Using a vapour membrane also draws in moisture into the wall, so it is really important to use the right insulation system here. Breathable systems can be used without a vapour membrane (unlike the conventional insulation systems that either have built in vapour control, or require a separate membrane). This lack of barrier makes the system a lower risk in the long run.

Research is showing that a safer U value to aim for, is around 0.7 to 0.8. This means that many thick walls may already have this type of value and so not need any insulation. However, most walls are around 1.51, so in order to get down to 0.7 you only need 40mm of wood fibre board. Having a wall that allows a little more heat through it than recommended by Part L is important as this helps to keep the wall dry and safe. 

If installing IWI it is also really important to remember thermal bridges. So reveals, between floors, fold backs along party walls etc need to be assessed and treated appropriately.

If using a wood fibre system you would need to use a breathable finish on the walls. So a lime plaster skim and a claypaint would be ideal.

Thursday, 26 March 2015

Damp proofing a typical Welsh terrace wall

Typical streetscape in Cardiff
Can you stop stone and brick walls from getting damp?

The simple answer is YES, but there are a range of issues surrounding the question and the answer!

The main issue around whether a wall is damp or not is that diagnosing damp is an art not a science per se. Common damp meters use electrical resistance to measure damp and this is fine for timbers, but for walls it requires a lot of interpretation. High readings can come from salts in mortars, old lead based paint etc, so not always water. So where you take measurements can radically affect the advice that you are given. So some companies who are trying to sell you damp proofing measures can use these meters to show that you need treatment when you might not.

So that's the issue with defining whether you have damp, but assuming that you do actually have a damp problem the next issue is where is it coming from.

We have all heard of rising damp, but many houses in Wales suffer from penetrating damp. This is water that is blown, or diverted into the structure. This can be through cracks in pointing, cracks in render, leaking rainwater goods, blocked guttering, failed seals around doors and windows, ...

Damp can also be caused by condensation. This might be due to poor heating, ventilation, high humidity from indoor activities. Again this needs to be assessed by looking at heating and ventilation strategies and infrastructure. Do the windows have trickle vents, have the chimneys been blocked??

Rising damp might be due to a range of factors including external ground levels, the presence of replacement concrete floors, blocked under floor ventilation, ... 

As you can see, damp can be difficult to diagnose. However, it is really important to ascertain where the source of any unwanted water is coming from.

Once you know what the problem is, you can start to find the cure. However, the cure will be influenced by the history of the building and the materials that were used to built it in the first place. This means the make up of the basic structure and also the materials used to repair, maintain and develop it over time. This building pathology work is key to refining the diagnosis and will hence help lead to an appropriate solution being found.

I cannot go into any great detail here as each building is different and requires specialist individual advice. However, the question was is it possible to damp proof these old buildings. The answer you might remember was yes, so what are the solutions?

1. Rising damp

If you do indeed have rising damp then you might need to:
  • Lower the external ground level
  • Re-instate ventilation under the floor boards
  • Remove cement render from the outer walls
  • Re-point the bricks / stone with a lime mortar
  • Re-render using a lime render
All of these are potentially permanent solutions, however they are fairly major bits of work, so most people just want to inject something into the wall. This is potentially possible and it depends on a range of factors, one of which is whether the wall is made from solid brick or stone. These walls are fundamentally different in their nature and it is easier to apply modern injection treatments to brick walls. 

Damp that is rising in a brick wall can be treated quite effectively using creams like DryZone. However even here you see companies injecting the damp proof cream into the bricks rather than the mortar. So with care this type of product can be part of a solution (but not if your damp is due to condensation or penetrating damp). However it won't work in stone walls (unless you have an even mortar bed at the correct height - like in ashlar walls).

Stone walls are fundamentally 'moist' in nature and so need a more holistic approach that is based on material science. The solutions here are much more likely to follow the bullet pointed measures above. It might also need to be combined with addressing ventilation issues, as stone walls need to dry out by the movement of water from the water to the outer and inner surface. 

2. Condensation

This tends to be more due to high humidity in the building and so a balance needs to be found between energy efficiency, ventilation, insulation and behaviour. It may be that a house needs positive input ventilation, or that the old chimneys need to be unblocked and vented, trickle vents on windows need to be opened, humidity controlled extractors fitted, or just a clothes dryer installed in the garden / room with an extractor fan. 

3. Penetrating damp

Penetrating damp is generally caused by issues around poor maintenance of a property. However, it can be down to the use of inappropriate materials like cement render. Seals like silicon around doors and windows fail over time and rainwater runs down the surfaces and straight behind the sill. Cement render (is fundamentally inappropriate, but nevertheless covers the majority of stone and brick houses) cracks due to its brittle nature and traps water behind it. Gutters and downpipes need to be clear otherwise they can easily poor high volumes of water against (and into) walls. Poor drainage around the building can lead to water sitting against walls,  I could go on.....

As you can see, diagnosing damp and finding the correct solution is a bit more involved that just pumping in a load of chemicals. However, pumping in chemicals and using water proof cement is what we do in the UK to the vast majority of our solid walled houses. In fact many mortgage lenders insist on this type of damp treatment. What a shame, it is generally a complete waste of money and resources. A typical damp treatment costs around £4 to £5,000. Don't be fooled by guarantees and assurances, many are meaningless. A recent customer had a injected DPC installed and when it failed dismally she was told that it had been installed correctly and so she couldn't claim against the warranty!

We would always recommend that you use your money wisely and this means that it is better to find a permanent solution to damp. This requires time and knowledge to get to the correct diagnosis, It is not a quick trip around with a damp meter and a bill of £5,000. The answers are there, but you will generally need some independent guidance to find the right ones for you and the house.

Friday, 20 March 2015

Chimney Problems and Solutions

Chimneys are a potential source of water ingress and it is quite common to find damp areas around the chimney breast. So what's going wrong?

Well there are a few key factors to bear in mind.

1. Failed pointing. This is quite common as the chimney gets a lot of wind driven rain and this can easily get behind the mortar if cement has been used and where the old lime mortar has been eroded away. When repointing remember to use a breathable mortar (a lime based one). Whilst this does allow moisture into the mortar it also allows it to dry out again. So ensure that the mortar joints are scraped out (to a depth of twice the height of the mortar bed) and then get it moist and repoint using the lime mortar. This should be finished in a flush manner to the bricks. Make sure you replace any broken bricks as well.

2. Cracked flaunches. Flat surfaces are not good for waterproofing as rain can settle onto the flat surface and soak in. Maintaining an angle / slope on the flaunch is really important if it made from a porous material. Cracking here is very common (again when cement is used), so either use a lime based mortar (and paint it with a mineral paint for a long lasting breathable finish) or look at a replacement option with a impervious capping material. This will help to reduce any water ingress into the stack.

3. Chimney pot not covered. Cowls are really important as we need to stop rain water getting into the main structure. Depending on whether the chimney is being used or no, there are a range of options to help reduce the amount of rain that are able to enter the pot.

4. Flashing. It is quite common for flashing to be fixed with cement. This again cracks easily and hence should not be used. Flashing needs to be set into the brickwork properly, not just abutted to the chimney. The flashing should be a lead one rather than the modern 'fix' that is glued on. Where mortar has been used, again it should be a lime mortar should be used rather than cement.

5. Vegetation growing out of the stack. Roots from plants like buddlia allow moisture into the structure and so these must be removed and the resultant holes filled with lime mortar.

I would warn against using cement renders, water proofing paints etc as they are much more likely to trap moisture behind them in the long term due to the effects of wind driven rain. So using materials that breathe and also have some movement potential in them makes them more suitable for these high exposure elements of our homes.

If the chimney has too many problems to mention (and this can happen when cement renders pull off the finish on bricks) then you may have to render / re-render them. Oddly enough I would recommend the use of a lime render. Make sure that the render has a good cap though as even lime renders require protection from above, so the flaunch /capping is really important to get right.