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Saturday, 30 July 2011

Can you damp proof a solid wall?

Damp proof courses are a routine requirement for many old houses when you buy them. Surveyors reports will nearly always find some damp and hence will stipulate the need for a damp proof course to be installed. But is it possible?

The old walls of many of the terraces in SE Wales (and beyond) are made up of face stone and a rubble fill. This means that they are very thick and also in the main made of lumps of stone, broken brick and some lime mortar. There are voids everywhere and the stone can be a right old mix of different sizes, shapes and types. So trying to damp proof these with a pressure spray or cream is doomed to failure. Spray will just find all the cracks and voids and the cream will be pumped into a mix of voids, stone, brick and mortar. So these techniques really will have minimal effect. So are there any others?

I have written before on the blog regarding the use of breathable renders and paints and these can certainly be used to dry out a building if specified and used correctly. Maintaining air gaps and air flow under suspended floors also helps significantly, however for many people they are faced with owning a house that has been cement rendered and concrete floors installed, so is there an alternative?

Personally I think that there are two.

Where you have old brick solid walls, these can be treated by using the creams (injecting the cream into the lime mortar rather than the brick) and ensuring that the holes are filled in afterwards (otherwise rainwater gets into the holes and then cannot drain down and hence causes more damp!).

Where you have the solid rubble filled walls we have to be a bit more clever. There is a system called Electro-Osmosis where you introduce a small electric charge to the wall using titanium rods and these create a positive charge in the wall. Water carries a positive charge as well, so the wall repels the rising damp. See diagram below.

These trickle charge systems are really effective and are not as expensive as might be imagined. However as with all damp, any plaster / render effected might have to be replaced as they are probably affected by salts.

Friday, 29 July 2011

Insulation - U values vs decrement values

There are a range of issues with insulation and a major overlooked factor is decrement.

Insulation values are normally measured in U (the lower the U value the better the insulative properties). This measures the thermal resistance of products from one side to another. However this does mean that it does not take into account the time lag / decrement that certain insulations can give. So light weight insulations can be good at insulating, but they do not 'store' the heat within themselves. So a good U value does not necessarily mean a comfortable internal environment. A classic form of this is can be found in loft conversions. Often these get really warm in the sun despite lots of insulation.

Good decrement values can be found in heavier weight materials as these effectively store up the heat as well as providing resistance to heat loss. So the time delay in the heat passing through can become very important. Decrement is measured in hours, so to have a system in place that can delay heat passing through by 12 hours will even out the diurnal differences between night and day. This is especially important where you have a large difference in temperatures between day and night. In the UK this difference is not so pronounced and so we can do with a shorter time lag.

Heavy weight materials are not always very insulating though, despite having a high decrement value, so having load of heavy blocks is not the way to go either as these will not keep heat as well in the winter. This can be seen with older buildings where they have solid walls. The heavy stone and brick helps keep the building cool in the summer, but they are also cold in the winter and require higher amounts of heat to keep the warmth to a modern day acceptable level.

So the best solution is a heavyweight insulator. Does one exist?

Thankfully yes.

One of the best product types is wood fibre boards. These have an insulation value similar to sheep's wool, fibreglass, mineral wool, hemp etc,  but also have a decrement value of 1 hour per cm of thickness. So a 80cm board will give you an 8 hour decrement value. So in the high heat of summer(!) it will take 8 hours for the highest peak temperature on the outside to be transmitted to form the peak temperature on the inside. This delay by absorption of heat can really help to balance out the temperature fluctuations in a house and certainly in areas like loft conversions.

Due to the insulation values associated with wood fibre boards as well they act as great insulation in the winter.

Another advantage of using wood fibre boards is that they are breathable and hence can be used in conjunction with older solid walled buildings to preserve the overall breathability of the structure. Fibre boards can be used as internal or external insulation and work really well with lime render / plaster.

There are several manufacturers in Europe (but none in the UK). Some of the better known brands include:

Eco Home Centre can access Hofatex boards if required.

Wednesday, 20 July 2011

Is there such a thing as sustainable carpets?

When you look at embodied energy carpets don't come out very well. Lots of energy can go into them in the form of:


So how can we get to lower 'carbon' carpets?

Well there are a few alternatives:

1. Re-used carpet tiles. Cleanstream carpets (based in South Wales) collect carpet tiles from offices, grade them and then sell them on. These tiles are about one quarter of the original cost and their A grade tiles look as good as new. Why waste tiles that have spent all their life under desks, cabinets and at the edges of offices? For more info have a look at what is in stock at Cleanstream Carpets website

2. Natural carpets. There are a wide range of accessible carpets made from natural grasses and materials - Sisal, Coir etc. A problem can occur with these when it comes to fitting. As a natural product the carpet will expand and contract slightly with changes in humidity and temperature. Carpet fitters don't like this and generally will refuse to fit it, as they offer a guarantee on the quality of installation. If they do fit they will use a huge amount of glue in order to try and stop the movement. This glue stinks and almost negates the benefits of the natural carpet in the first place. However these natural fibres are hard wearing and attractive.

3. Wool carpets. Surely a wool carpet is the best solution. We ll it can be, but many wool carpets are still high embodied energy as the wool is bleached and dyed before use and also can have a synthetic backing and conventional glues. Again they are hard wearing and are much more stable and hence there is no problem with fitting.

So is there an alternative?

There are a few manufacturers however that make un-bleached and un-dyed wool carpets that have natural cotton backing and natural latex backing. These are stable in their make-up and hence present no problem with fitting or guaranteeing. Due to the use of minimally treated natural materials used in the manufacture, the embodied energy is radically reduced in these products.

Underlay and glues

Before we forget there are another couple of elements here.

Underlay. There are a range of choices here that are eco-friendly. You can use: Recycled cotton (felt) and recycled tyres (rubber) are excellent uses for recycled products. The tyres are good for stairs and the felt for living rooms. Do not use the foams as these off-gas and also slowly degrade and you end up with a dust after a few years.

Glue. If carpets are fitted properly you do not need to use glues. Fitters don't like this, but insist! The glue is really smelly and can make the room uninhabitable for a few days.

One manufacturer of natural woollen carpets is Alternative Flooring and their Eco Collection.

What to do with DIY / Home Improvement Waste

When doing improvements at home there is always an element of waste created. This might be in the form of plasterboard, hardcore, old furniture, wood etc. Much of this can be recycled at municipal recycling centres and this is a good option, however you can go some additional good by using community recycling organisations. These are often social enterprises that support unemployed and young people. They also can often take this waste and re-use it rather than recycling it (this is better environmentally).

So where to find this community organisations? Thankfully there is a new website run by Waste Awareness Wales and Cylch that allows you to find your most local community recycling facility. Visit: 

Friday, 15 July 2011

ACE Solar Panels - FREE electric (when the sun shines!)

Ely and Caerau are wards in Cardiff and are part of the Welsh Government's Communities First scheme. They have been working hard to make the project sustainable in the longer term and part of this drive has been to create ACE (Action for Caerau and Ely). FuturespACE is a new venture looking to install solar PV panels on people's homes in Ely and Caerau initially, but it will be extended across Cardiff.

So if you (and preferably a few close neighbours) have a south facing aspect to your roof and want to take advantage of some free electric when the sun shines for no capital cost to yourself it is worth contacting ACE to see if you can get involved.

Note that in order to get the most out of  the PV panels (which will on average generate around 2kW - enough to power a kettle) you will need to be using the electricity when the sun is shining around midday. So this explains why we have timers on washing machines / driers / bread makers etc. Set electrical tasks to be done during the middle of the day and you will get the most value for money out of the panels / ACE project.

Contact details for ACE are (029) 20873664 or

Thursday, 14 July 2011

Draughty floorboards?

Old floorboards were natural draughty. When they were installed we didn't have tongue and groove flooring and the boards were not always particularly straight. Time, wear and tear, moisture content changes in the home etc have all contributed their little bit towards more ill fitting boards. The floors themselves need a draught underneath to keep the walls dry. A good draught wicks away moisture from the soil below the floors and the lower portions of the walls, thus helping to keep rising damp at bay.

The following solutions will look at how to keep the existing floorboards (with all their character and charm) rather than the potential horrors of laminates and replacement concrete floors.

With energy efficiency now being a real driver we are faced with a situation where we really need to make these wooden floors fit for the low energy age. This can actually be a simple task, but as ever there are a range of different ways of achieving this. The simplest way is to just draught proof them using an expanding 'V' shaped plastic product. Basically this 'V' is pushed down into the gap to provide a seal in between the boards. This 'V' is initially compressed and it naturally expands out to take into account the variable width of the gap. This is a Welsh product that will be available from the Eco Home Centre soon. more info can be found at This solution can radically reduce draughts, but it does not insulate the floor.

To insulate and draught proof takes a little more work.

To improve the efficiency of the floors we need to get some insulation into them. This insulation should be breathable because if we use non-breathable insulation it will trap more moisture below the floor and also concentrate any moisture movement through the breathable elements (i.e. wood) and both of these will increase the chances of rot. So using breathable insulations like cellulose, sheep's wool, hemp etc is really important. Similarly if you use any membranes then these also need to be breathable.

In its most basic form we need to put insulation between the floor joists. This can be done from below (if you have a cellar or a large void under the house), or more commonly from above (this means taking up the boards to gain access).

If working from below insulation can be wedged between the joists and then a breather membrane / netting can be stapled to the joists to keep it all in place. If using a breather membrane (this acts as a better airtightness solution) then use a good quality sealant to join the membrane to the walls at the edges to ensure that draughts are not created under the skirting boards.

If working from above then lift the boards and then you can drape the membrane / netting over and down the joists to create a base for the insulation. Again use a really good sealer around the edges of the room and also remember to tape up the strips of membrane to ensure an airtight finish. Insulation can then be added and the joists replaced.

Draughty chimneys?

Chimneys need to be draughty in order to work, but if you are no longer using them they will represent a major element of heat loss in the home. However many people want to keep them intact either for aesthetic purposes or for occasional use (after all there is something about having a real fire on a cold winters night).

This represents a series of choices in what to do with a chimney.

So if you want to use the chimney occasionally then you need to have a way of sealing off the airflow in a easily accessible manner. The most common way of doing this is to use a 'Chimney Balloon'. This is a simple hardly plastic balloon that is inflated in the flue and effectively stops any airflow up the chimney. This is fine, but you also need some airflow in order to keep the chimney dry. Ummm. The solution here is to stop water ingress from above. To do this you can fit a number of attachments to the chimney pot to create a cover over it. Common names for covered pots include: Hooded, Mushroom, Saucer, H Pot. These can be retrofitted quite easily, but do need access to the roof of course. With these fitted you can effectively stop excessive water ingress, keep the flue open at the top and then reduce air flow at the bottom with little fear to damaging the flue.

If you are no longer using the chimney you can fit a much cheaper plastic removable cover over the chimney pot that acts in several beneficial ways. It will stop water ingress, reduce the chances of birds nesting on the chimney, stop insects nesting in the chimney and also allow for some trickle ventilation. The most common of these is the Chimney Cap. Combined with a Chimney Balloon it will allow you to keep the chimney intact whilst reducing the air loss. It also means that in the future if you wanted to restore the chimney / fire place into working order it is a 'simple' case of removing the cap and balloon.

Other solutions include making a 'Register Plate'. This is a metal sheet that acts like the chimney balloon. They are commonly used in fireplaces when installing a stove. Two simple holes are made into the metal sheet for the flue and for cleaning. The cleaning one has a flap on it for easy removal (whilst also preventing air loss) and the stove acts as the heat source and also limits the draughts much more than an open fire.

So remember that draughty chimneys need a little more thought that just adding a Chimney Balloon as you need to manage water ingress as well.

Wednesday, 13 July 2011

A compostable paint tray? A way of rejuvenating dried up paint brushes?

Eco DIY is expanding the boundaries of influence. Where once we were limited to high quality paints, we now have a growing range of other accessories to assist the Eco minded family.

Eco Solutions is a UK company making a wide range of 'removers'. Few things seem immune, their range includes:

Nail varnish
General dirt from hands

All of these are designed with 'science not solvents', so we are really unsure about how they work, but we have tried out the paint, graffiti, artex and general dirt products and all work really well. No nasty fumes, no need for a load of Personal Protective Equipment (PPE) and things like the Graffiti Remover can be used by children / young people, so it is ideal for schools / youth clubs to get any known perpetrators to actually clean their work off again (if inappropriate to the wall of course).

Compostable paint trays are also new. Made from recycled paper they are ideal for using with natural paints because, if you are a person who doesn't like the cleaning associated with painting, you can compost the trays after three uses with the natural paint dried up in the bottom of it.

Paint brushes are now available with a host of eco credentials. Bamboo handles, recycled steel ferrules, natural bristles combined with recycled filaments.

There are also rollers and trays made out of recycled plastics.

Fillers are also available made from talc and lime so that they are breathable, easy to use and sand and give an excellent finish. Auro have an internal talc based powder filler, whilst earthborn have a 'white cement' filler that is suitable for both inside and out.

So high quality products to complement high quality natural paints are here!

Saturday, 9 July 2011

Windows a wise investment?

When we think about energy efficiency one of the first things that we look at (or through) are our windows. This is actually a really expensive option for improving energy efficiency compared to its return. We generally only lose around 10-15% of energy through doors and windows. Most of our heat goes through our walls and roofs. However if our windows and doors are draughty then this figure can go up to around 25%. Replacing doors and windows will cost between £500 - £1500 per door and £200 - £800 per window, plus fitting and the associated disruption. So it is not a easy option even if you used the cheapest options.

However for the sake of this post we are assuming that the windows need to be replaced, so what are the various choices that face you. These include:

  1. Design of the windows (windows bars, number of opening casements etc.)
  2. Workings of casements (inward opening, outward, reversible, fixed, escape route etc.)
  3. Material used in the frame (wood, uPVC, aluminium, other)
  4. Type of glass (Double glazed, triple, argon filled, reflective glass etc.)
  5. Furniture (lockable windows, colour, style)
  6. Maintenance (accessibility of the windows, material maintenance requirements)

In an ideal world we would all get really efficient, FSC timber framed windows HOWEVER, in the UK we have no fitting standards, so we tend to use the quickest, easiest and cheapest way of doing this. This means lots of expanding spray foam, silicon sealer and cover strips. So we are fitting high quality windows in a way that is not very weatherproof, insulating or airtight. In parts of Europe there are RAL and EnEv standards for window fitting that ensures that windows are:
- Weather proof on the outer edge
- Insulating in the mid section
- Airtight on the inner edge
Using these principles is really important if we are to get the best performance out of our new windows. The great old British way of 'it will do' is no longer good enough.

So, things to think about when choosing windows are:

1. Design of the windows (windows bars, number of opening casements etc.)

The design of your windows can radically alter the look of your house, so care and thought is required when choosing. Like for like is the most common choice, but you can make a real statement by choosing different styles, colours and configurations of windows. Material will also have a large impact, so using uPVC on older buildings can look really out of place.

2. Workings of casements (inward opening, outward, reversible, fixed, escape route etc.)

How casements operate makes a big difference to ease of use. On first floors and above using inward opening windows allows for easy maintenance and cleaning. Outward opening reversible windows do the same, but they are not so energy efficient as the inward opening ones. You might also have to allow for emergency escape routes.

3. Material used in the frame (wood, uPVC, aluminium, other)

Being an Eco DIY blog we are obviously recommending the use of wood rather than uPVC. Wood is a natural lower embodied energy material that can last a lifetime and be repaired easily if required. uPVC requires maintenance and is much more difficult to repair and recycle (and comes from a non renewable source and has a high embodied energy). If you are worried about longevity, you can clad wood with aluminium and this effectively makes the windows maintenance free. Aluminium gives a stronger frame and so can have slimmer frames, but it does carry a really high embodied energy, but is effectively maintenance free.

4. Type of glass (Double glazed, triple, argon filled, reflective glass etc.)

Double glazed is fine for the UK climate, but on north facing aspects then triple glazing is a choice. For most refurbishment work choosing a window with a U value of 1.2 - 1.4 is fine. Only if looking for a really energy efficient is it really worth going for windows with a U value of below 1.2. It is worth noting that various gas fillings will slowly leak out, so if you are looking for a longer term solution then air-filled triple glazing will do this. Bear in mind that you will might have to have certain types of glass for security / safety reasons. For most applications standard glazing is fine, but for certain buildings you might want to look at coated glazing that can help to insulate or cool buildings. For really inaccessible areas, you can stipulate self cleaning glass.

5. Furniture (lockable windows, colour, style)

The colour and style of furniture is important, as is security (for insurance and piece of mind).

6. Maintenance (accessibility of the windows, material maintenance requirements)

Wooden windows have been around for years and good quality slow grown timber (from Northern Europe or North America / Canada) is perfectly fine for windows. But for an even longer life then hard wood is better (oak, meranti and sycamore). uPVC does require maintenance and should be painted with a UV protector, so don't be fooled into thinking that they are maintenance free. Specifying inward opening windows does make maintenance easier and cheaper. Aluminium cladding also reduces maintenance requirements.

Eco Home Centre is a retailer for ARU Joinery and also stocks Iso Chemie Window Tape and Osmo Window Paint.

Tuesday, 5 July 2011

Flushing carbon down the pan

We often forget that water has an embodied energy (all that pumping around the system and then cleaning it all up afterwards) and so it is a resource that we need to look after. But how best to do this?

One of the things that we are told to do is to reduce the amount of water going through our toilets. This is a very sensible suggestion especially for offices, businesses and other organisations (as well as for us all at home). So what is the best solution?

We need a system that is the most efficient that it can be (you only use the water that you need to use, not a fixed amount per flush)
We also need a solution that is reliable and maintenance free (i.e not a valve system)
Ideally we want a solution that does not require the replacement of the toilet furniture (so a replacement for the inner workings of the loo rather than a brand new toilet)
We also want a solution that is easy to fit without the need of a plumber (a competent DIY job in other words)

Does this ideal exist?

Thankfully yes!

There are a range of replacement siphons that can easily be retrofitted into a cistern and there are also some adapters that make the toilet flush infinitely variable using the existing siphon. So the main choices are:

1. Interflush - Adapter (this is suitable for side handled toilets with siphons)
2. Interflush - Replacement siphon (for use in all toilets, except close coupled ones)
3. Mecon - Adapter (suitable for plastic cisterns or ceramic ones with blanks)

1. Interflush. This is a system that has a default of giving a minimal flush. Just hold down the toilet handle for as long as required to clear the pan. Easy to fit - takes about 10 minutes. Competent DIYer with a drill can fit this. Gives you a 50% saving on water use.

2. Interflush Siphon. This replaces the existing siphon / valve system with a brand new siphon. However this siphon has a patented diaphragm that should last decades, thus making this solution infinitely variable and also incredibly reliable.

3. Mecon. This system also gives an infinitely variable flush, but its default setting is for a full flush, so it still has the potential for a 50% saving, but in most situations will probably give a little less due to incorrect use.

These devices can save you a packet of money (if you are on a meter) and are expected to give full payback within a year. Not only that it is year on year carbon savings for you, your company and for all of us.

Suspended timber vs solid concrete floors?

Many old houses were designed with suspended timber floors. These were designed into houses to keep them dry (at the expense of draughts). The timber joists and floor boards were vented underneath at the front and back of the house to allow a draught to whisk away any rising moisture from the foundations. As long as the vents are open and working and that any intermediate supporting foundation walls retain their air gaps this system can be very effective for keeping moisture out of the wood and hence preventing rot and damp. However these floors can be very draughty and hence energy inefficient as the only material between the house and the outside world is an inch of wood.

In response to draughty floors and some rot in the ends of joists we now commonly  replace floors with solid concrete floors. Many of these floors are just solid concrete, most have been fitted with a Damp Proof Membrane (DPM) underneath and some later ones have some insulation installed (the insulation tends to be beneath the slab and also not along the edge). The theory being that the moisture is stopped by the DPM and the wood replaced with a rot-free solution.

So concrete floors are draught-proof, can be insulating and also provide some thermal mass (especially helpful if used in conjunction with underfloor heating / passive solar gain). However, it also drives any rising damp up the adjoining walls. Water will always find a way to escape and if the only option is up an internal wall, so be it. The installation of a solid floor can also block airflow to other rooms. It is common for one room to have its floor replaced. This then can cut off the underfloor ventilation to other rooms. This is turn can cause more problems for the other rooms. So great care is required to ensure that ventilation is maintained where required and that damp is not brought into the house.

Personally I think that wherever possible suspended timber floors should be repaired (the ends can rot) and then the floor be properly insulated and draught proofed. This then gives you a cheaper, less resource intense and future proofed solution that maintains the character of the home as well as not bringing in the potential for damp in the walls.

If insulating the floor then use breathable insulation (as this allows the whole of the floor to breathe) and also a breather membrane (this allows you to create an airtight seal to reduce draughts) and also for any moisture to pass through and dissipate naturally. Care needs to be taken when fitting the membrane as it needs to be taped together to form a consistent barrier and also to be attached to the underfloor walls using a long lasting sealant. Look for products like Orcon F rather than relying in silicon sealers. Conventional stuff just doesn't last long enough.