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Tuesday, 24 January 2012

Should we insulate solid walls?

There are a wide range of issues associated with insulating solid walls and this has been illustrated by some of the results seen with the ARBED 1 programme in Wales. With our current obsession with energy and carbon we have tended to ignore the advice of conservation builders and eco-builders and taken construction detailing decisions from the mainstream industry. This has meant specifying high efficiency insulations like polystyrene and other non-breathable insulations for terraced housing.

On paper the efficiencies that this type of material brings are impressive, unfortunately, it is just incompatible with the majority of terraced housing. So, we are now seeing issues like:
  • damp internally (associated with non-breathing external insulation)
  • mould growth (associated with poor ventilation and non-breathing external insulation)
  • cold bridging (associated with poor installation of insulation)
  • external finishes failing due to frost damage (associated with internal insulation)
Even the folk at BRE are now aware of these issues, but their focus is on more research rather than stopping this madness that we are inflicting en masse to our terraced housing stock.

CADW are thinking about trying to change the default situation with regards to insulating solid walled buildings, i.e. having to get permission to install wall insulation, rather than having to apply for not insulating (as per current situation). In the age of carbon reduction this seems like madness - not insulating walls?? However the rationale behind this stance is set to become better known and appreciated. We have already found that solid walls insulate a lot better than computer programmes tell us (see earlier blog about the SPAB report), we also know that dry walls are up to 38% more efficient than wet ones. So why not just let the walls breathe and remain dry?

By using insulation we can ruin this natural process and hence cause problems. If we insulate the outside we alter appearance etc and we can also radically change the breathability of the structure. If we insulate the inside we reduce the amount of warmth flowing through the walls, but then this can lead to problems with the outer surface of the walls as the wall itself is colder and hence more prone to damage through frosts etc.

If we did nothing (apart from ensuring that the wall could breathe properly) then the walls would do what they were designed to do and this is much healthier both for the walls and the occupants. A few coats of limewash or silicate paint to provide a wearing layer for the structure would be enough to help keep the walls dry, as efficient as they can be and also cost us all a lot less in the short and long term.

Personally I think that these decisions need to be made on an individual basis as each house if different. However, overall guidance would be that you always need to:

  • use breathable insulations on older solid walled houses;
  • maintain a breathability gradient from the inside to the outside (inside less breathable than the outside);
  • ensure that internal insulation is designed to allow some heat through;
  • ensure good detailing work especially around window reveals etc;
  • keep walls dry using breathable paints and finishes.

Eco Home Centre E-Shop working again

Hi All,

Just a quick message to say that the Eco Home Centre Shop is up and working again. An issue with cloud IP addresses or something. Ummmm..

Anyway, remember that prices are going up in Feb so best hurry up with planning any DIY / decorating!!

Tuesday, 17 January 2012

How to buy a good door

People look at a range of factors when buying doors, but the principal ones are: materials (uPVC, wood or aluminium); type (glazed, solid etc.) and; price. Style can come into play as well as this dictates the look of the house / building.

I think that these considerations could and should be widened to encompass a range of factors that are actually really important to the success or not of a door. The important issues that I think are overlooked by most consumers are:

1. Energy efficiency - with ever growing fuel bills the importance of a well insulating door will only get greater. Standard UK doors are 44mm deep. This limits the amount of insulation that can be gained.  However, if you look at standard European doors they start at 60mm depth and go up to 78mm. This extra depth allows for more insulation and also has the welcome effect of making a door feel, sound and be a lot more solid. Some of you might know that feel of an European door and how it compares to an UK one.

2. High quality locking mechanisms and door furniture - many cheaper doors in the UK have low quality locks and this can lead to a number of problems. Always look for a good quality set of door furniture. Top manufacturers are companies like ASSA Abloy and ROTO.

3. The use of sustainably sourced timber - I think that all doors should really now be sourced from registered sources (look for FSC or PEFC marked wood), however some of the hard wood options might still be coming from unregulated sources.

4. The use of engineered timber - The use of engineered timber is really important in a door. This is a system that cross laminates timber to give the door higher strength and also reduces its likelihood of warping. I have seen some lovely solid oak doors that have warped and hence don't fit any more and were really draughty.

5. Specifying a door with an integrated frame - buying a door and frame separately, or just fitting a new old into an old frame, almost invariably means that there is a less than perfect fit. Old hinges, locks etc and just the movement of frames means that getting an airtightness finish is very difficult. So buying a door with frame together is a better option.

6. Ensuring that the frame is a hard wood - soft wood frames are not as strong as hard wood ones, so for long term stability it is better to specify a hard wood frame.

7. Getting it fitted correctly - it is great to have a new energy efficient door, but you need to have it fitted in the right way. On the continent there are standards, but the UK is devoid of them. RAL standards require any fitting to be a. weather tight, b. insulating and c. airtight. In the Uk we rely on a thin silicon seal and some expanding foam. Not ideal.

The style of doors and windows is key to the look of a building and so it is important to get it right, so spending some time exploring different options is important.

At Eco Home Centre we deal with ARU, who produce excellent doors (and windows), so check out what the options and specification are. So next time you are looking for a new door hopefully you will bear some of these factors in mind.

Friday, 13 January 2012

Fed up with paint bubbling off of stone work?

External stone work has a real habit of shedding paint. It peels, bubbles and dusts off. This is because masonry paint is designed to be waterproof. Stone on the other hand generally isn't. The stone that we use for mullions, key stones etc tends to be limestones and sandstones. These are porous materials and so if any water does get into the stone (and it invariably will) then it will want to get out again. If it is blocked by an impervious layer then it will force this covering off. Water is a very powerful element in buildings.

So the masonry paint will then be blown off of the structure. However this then lets more water in and this again is trapped by the paint and this can damage the underpinning stone. So your lovely stone features will not only look tatty it will be structurally damaged as well. All this for just not choosing the right type of paint.

Up until now, we have been recommending the use of silicate paint, however it has only been available in 10 litre pots from our supplier - earthborn. After, what seems like years of nagging on my behalf, they have come out with some smaller sized tins. Hooray!

Earthborn now produce a one litre primer (this has to be applied directly onto the stone, so you will have to remove the existing paintwork) and 750ml pots of the silicate paint itself. This is much cheaper and produces a lot less waste.

With a breathable paint on the stone (and it can also be applied to lime render, cement, brick etc) then you will have a long lasting paint that works with the underpinning substrate rather than against it. Marvellous.

To buy earthborn silicate paint from Eco Home Centre just click on this link


Saturday, 7 January 2012

Passiv Haus, is there a better alternative?

Wales has been slowly moving towards using the Passiv Haus Planning Package to design and construct Passive Houses (Passiv Haus). The Ebbw Vale demonstration buildings used PHPP extensively to create very low energy homes. The Lime House and Larch House at the Future Welsh Homes site show how the principles of managing air within buildings can radically reduce energy consumption. The Passiv Haus principles are fairly simple.

Make a house airtight and then use heat exchange systems to take the warm, moist and stale air out and use it to preheat the incoming fresh air.
Use the orientation of the house to utilise free solar energy to help heat the home.
Use good insulation to keep the warmth in during the winter and the summer heat out.

Using the above principles you can relatively easily create homes that only use a maximum of 15kWh per square meter per annum. This is about 10% of an average home's energy consumption. So with the pressure on carbon reduction this is a good thing.

However, I think that there are some issues with using Passiv Haus that is not being talked about.

1. The system works by managing the whole house, so this means that all the rooms in the house are the same temperature. We are used to having cooler bedrooms and warmer living spaces, so this is a fairly major cultural change, especially if you did not build the house. This for many may not actually be a problem, but people need to be made aware of this characteristic especially in the rental market.

2. The heat recovery ventilation system is designed to manage the volume and quality of the fresh air coming into the home. So on sunny days our natural inclination is to open windows, but this can effect the system (unless it is on summer bypass mode). So for the best efficiency you need to keep windows and doors closed when heat is required in the house. The trouble is that people associate fresh air with having windows and doors open and so having them shut goes against the way that we have lived until now and I think that again the rental market might find this feature problematic.

3. The Passiv Haus in Ebbw Vale (part of the Future Homes Project) also has to have an automatic blinds system to stop the house from overheating. These are activated even in the winter if the house is too warm as the sun's passive heat can effectively heat the building through the glazing (such is the efficiency of the insulation in the building). Again this would not effect the self builder, but the tenant might not be happy to lose this view etc without being asked. This was certainly the view expressed by visitors to the building.

4. Heat Recovery Systems have sets of controls that need to be used. They are not complicated, but again they are very different in concept to conventional heating. On the house in Ebbw Vale you needed to turn the dial up to decrease the temperature, effectively you are turning up the volume of extracted air (for when cooking etc). This again is not a problem for most people, but I think that many social housing tenants will not get the instruction that they need to ensure that the system works properly and effectively.

These might be little issues when compared to the energy saving that Passiv Haus design and construction can bring, but I fear that it will mean that people do not live in the optimum manner due to their habits built up over time living with conventional housing, especially in the Social Housing market.

I think that there is a gap in the market for a more natural system and that this might be filled by the Bio-Solar Haus concept.

Thursday, 5 January 2012

Black lime mortar and how to replicate it

Many buildings South Wales are famous, in the construction world, for their black mortars. Many a householder has drilled into Victorian walls to find a fine cloud of black dust emanating from the hole. People replastering and rendering walls have had to cope with cleaning up a layer of black ash from their homes.

This has caused black mortar to get a bit of a bad name, however its history is based in the mining and manufacturing base of this area. In order to make a good mortar you need to have a fine aggregate and what finer, and cheaper, aggregate than the dust and ash from the industry abundant in the area at the time. This ash was mixed up with lime putty to make a mortar and render mix that was strong enough to the service the construction industry of the time. So these old black mortars are a rich reminder of the industrial heritage of the South Wales region.

However, lime mortars now come in a base white / off white colour. Lime putty mortars mixed with a limestone aggregate are certainly too pale for repointing. Some companies will match colours for you, but then you are at the behest of the type of aggregate that you are offered etc. This is also an expensive option when looking at doing small areas of re-pointing.

So we would recommend the following solution:

Buy the right mortar (lime putty with limestone dust aggregate)
Buy a lime tolerant black pigment (earthborn do one of these available through our E-Shop)
Mix the pigment with some water and then knock up the mortar and pigment to get the right shade.

Happy Black Re-Pointing!

Claypaint prices to rise

Hopefully you will all be aware of the particularly good quality claypaint that is available from earthborn (via the Eco Home Centre E-Shop of course!). We have just had the heads up from earthborn that the prices will be increasing in February. At present we sell the white at £39.99, but RRP will be £47.87 from Feb. We shall continue to give our permanent discount of around 10%, but even so this will mean a price rise of around £3 per 5l, so around a 10% price rise.

The increases will be across the Earthborn range, so including their emulsions, pigments and masonry paints, so if you are planning some decoration over the coming months, it would be a good idea to get your paint ready now and save yourself 10%.

Note that Auro are also changing prices soon, but this might mean some reductions in price for some products, whilst others increase slightly. The price of orange oil has dropped from last year and this is one of their key ingredients that dictates production costs.