Author Topic: External insulation for older properties  (Read 12053 times)

Adam Claridge

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External insulation for older properties
« on: July 04, 2006, 01:50:23 PM »
A previous thread seemed to receive no responses regarding external insulation, but it seems such a potentially important area.  As, I think, David Olivier has drawn attention to in other threads, Germany is concentrating a significant resource on the superinsulation of existing buildings, much of which is external.  Many people, myself included, live in older single skinned properties (and generally like doing so).  The general qualities of many of these properties is why they continue to be popular. 

However, one of their serious deficiencies is excessive energy use, typically due to their minimal insulation.  I have contacted as many of the external insulation companies as I can to ask for a survey and quotation for my typical end-terrace property.  Over a year I have had just one response, and that from a system I would be reluctant to use and which seems to provide only a small improvement in insulation (and at vast expense).

Are there any companies out there who are interested in smaller domestic external insulation projects and does anyone have any personal experience of them. Also, if there are companies prepared and competent enough to do it, is anyone aware of any grants available to help subsidise the costs?

Nick Grant

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Re: External insulation for older properties
« Reply #1 on: July 05, 2006, 08:06:03 AM »
But how to do it?

I don't have personal experience as have taken the easy option of new build but a few leads:

Energy efficiency good practice guides from EST:

External insulation systems for walls of dwellings (CE118 / GPG293)
http://www.est.org.uk/download.cfm?p=1&pid=253

Advanced insulation in housing refurbishment (CE97)  http://www.est.org.uk/download.cfm?p=1&pid=248

John Willoughby wrote at least one of them.

Websites of people who have done it:

George and Annie Marshall's Yellow House, discussed in other boards.
http://www.theyellowhouse.org.uk/

Penney Poyzer and Gil Schalom's Nottingham EcoHouse:
http://www.msarch.co.uk/ecohome/

Both used rigid foam insulation but an alternative is moisture permeable woodfibre as sold by NBT
http://www.naturalbuilding.co.uk/

Nick

Adam Claridge

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Re: External insulation for older properties
« Reply #2 on: July 06, 2006, 03:14:18 PM »
Thanks for your reply Nick.  The resources you quote are excellent, but the problem I have still remains - I cannot find an installer to give a quote (I have contacted their trade body, again, and will share any positive results I get).  Bearing in mind some of the detail that needs to go in to such an installation I am unlikely to use a 'general' builder and I certainly do not feel competent enough to do it myself.  Are any installers members of AECB I wonder - if you are please let us know; I'm sure there are a number of others who might also be considering this route forward.

Dan England

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Re: External insulation for older properties
« Reply #3 on: July 07, 2006, 10:12:27 PM »
I run a small building firm and that's just the sort of project we'd undertake. The reason it's not so widely available is that there's no mass market demand, the technology is awkward and requires a lot of detailing, and it would be very hard to make money from. The only way to make decent money in the building business is to specialise - decide on one operation, invest in the equipment and train people to be able to repeat that one set of tasks. The less skill and training required the better, obviously. There are a lot of companies around making money from cavity wall insulation because it fits those criteria. I'm sure if the concept of external insulation for single skinned buildings becomes more widespread and there are more people actively wanting it done, then there will be companies set up to specialise in it. It's a difficult business to standardise though, because of various potential problems - how to finish the border with adjoining properties, how to detail around window recesses without leaving weak points for water ingress, how to deal with roofs where there is minimal overhang. It would be a difficult business to guarantee for the same reasons, and also because the quality of the rendering work is crucial, and there are not many plasterers who have the patience to apply render in a way that can genuinely guarantee it won't crack after a few years.
It's difficult, as a builder, to simply read about new techniques and then start doing them. Building is something that traditionally has always been passed on from one individual to another, with all the little tricks and knacks that go with it. That's why most builders don't even want to hear about new techniques - they've spent a long time learning how to do things properly one way, and there's no motivation to have to go back to square one.
Personally, I get a lot of pleasure out of learning new techniques, but it's daunting, especially when trying something for the first time which is costing a customer a large amount of money and which I'm taking full responsibility for.
I think there is a real need for some form of national education program to teach people in the industry about eco-principles and detailed hands-on techniques. But that could only happen with regulation that made it mandatory, the problem then being that if people are forced into something, they're more likely to approach it with a negative attitude. Like everything else in our society, things will only change seriously when climate chaos keeps disrupting business as usual on a serious and regular basis, and the media machine starts working itself up into a self-righteous fury about 'why nothing has been done to prevent this outrage'....

David OLIVIER

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Re: External insulation for older properties
« Reply #4 on: July 09, 2006, 11:53:59 AM »
At least external insulation improves the building's durability and freedom from condensation in almost every way (unlike internal insulation, which is fraught with risks and must be done extremely thoroughly in order not to shorten the life of the building).

A BRE report in I think 2005 quoted a guide price of £40-50/m2 for external insulation - not sure for what thickness, but makes it excellent value as a fuel-saving measure. It probably means the price for doing more than one house a a time. Perhaps you should contact BRE and put their knowledge re installers to the test.

Also, Prof Bob Lowe built an extension to his house in Yorks. using 150 mm external insulation. The supplier was Envirowall. 150 mm is about the thickness needed if you want to reach Silver Standard. It's not enough for Gold/Passivhaus - which the Germans are aiming for on all buildings where external insulation is permitted (not listed buildings and presumably not buildings which face directly onto the pavement).

David.

Andy Simmonds

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Re: External insulation for older properties
« Reply #5 on: July 24, 2006, 09:13:32 PM »
very important. no grants i am aware of - sadly as I am gearing up to deal with my own (8" thick brick walled) house.

Am actually on holiday, just having a quick look (cant keep away) - but will post some ext. insulation leads when i return.

may be useful to look at generation homes web site.
« Last Edit: July 24, 2006, 09:16:52 PM by Andy Simmonds »

James Muir

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Re: External insulation for older properties
« Reply #6 on: October 03, 2006, 12:35:46 PM »
The Heraklith Tektalan-E21 external wall insulation system has been supplied on numerous one-off, small properties with various renders applied including lime renders.  The work has been done by an individual tradesman or small builder.  Application of the insulation boards and render is not difficult but, as mentioned by previous replies, it is important to get the detailing correct. Detailing the new external wall surface to adjacent property walls needs careful thought and discussion.

James Muir, Heraklith
« Last Edit: October 03, 2006, 06:34:26 PM by Nick Grant »

Dan England

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Re: External insulation for older properties
« Reply #7 on: October 03, 2006, 05:17:36 PM »
Can the heraklith boards be rendered straight onto, or do they need a layer of EML or cementboard?


Andy Simmonds

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Re: External insulation for older properties
« Reply #8 on: October 03, 2006, 07:20:58 PM »
James (as with other thread on this forum), one first needs to know the U value produced by this system (say as applied to 8" brickwork with lime mortar in my case), and the allowance to be made for the thermal bridging of the mechanical fixings in that over all U value.

detailing and other issues arising adjacent neighbouring properties as par tof such major eco refurbishments is one of the biggest challenges facing a serious upgrading of the existing housing stock!

James Muir

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Re: External insulation for older properties
« Reply #9 on: October 10, 2006, 10:39:22 AM »
Andy,
Based on my calculations achievable U-values externally insulating 8" brick wall:
8" brick+Tektalan-E21 100mm    u-value 0.35 W/m2K
8" brick+ Tektalan E21 125mm                0.28
8" brick+50mm battens with 50mm mineral fibre+
           Tektalan-E21 100mm                    0.24 W/m2K

I am asking colleagues in Austria on heat loss through dowel fastenings.
Note: Render reinforcement meshes are, I believe, recommended by all EWI system manufacturers.  Probably because relevant German standard requirement.

Andy Simmonds

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Re: External insulation for older properties
« Reply #10 on: October 11, 2006, 03:48:24 PM »
james,
this one looks interesting...would you be keen to run a set of details based on this system past AECB to assess how close to AECB silver standard this might be in reality?
If so email us and we could see if there is mileage in developing some silver standard details?

8" brick+50mm battens with 50mm mineral fibre+
           Tektalan-E21 100mm                    0.24 W/m2K

could also look at sheepswool cf mineral fibre as alternative?

would end up assessing thermal bridging from timber battens and any other fixings etc....then psi values associated with key junctions (wall corners, eaves, etc) and reach a 'real u value' for the system, cost it and hey presto.....

 

naughty-teens