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Multi-foil insulation
16-08-2010, 11:18 AM
Post: #1
Multi-foil insulation
Has anyone had any recent experience in specifying or using multi-foil insulation the likes of Tri-iso Super 10?

Doing a loft design and the contractor wants to use it. The manufacturers details don't indicate the use of any additional insulation and I recall there being an issue with this in the past.

Darren Bell (MCIAT)
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16-08-2010, 01:53 PM
Post: #2
RE: Multi-foil insulation
Hi
At the moment Tri Iso, as far as understand, does not have a BBA certification.
Many LAs do not accept any multifoils without BBA certification. Those that do have a BBA are acceptable providing they are fitted in strict accordance with the BBA cert.
To achieve the U-values required by the Building Regulations multi foils require additional insulation, typically around 55mm rigid foam. This extra insulation together with the depth of battens often results in the contractor opting for rigid foam throughout.
For a list of acceptable multifoils I would do an internet search for BBA and Multifoil

hope that helps

Dr R D Saunders MBEng, BEng(Hons), PhD
Developer of G-Calc 2010 - Part G Calculation software
Building Regulation Consultant and Senior BCO
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20-08-2010, 11:11 AM
Post: #3
RE: Multi-foil insulation
The BCO accepted the Multi-foil with an additional layer of 30mm Celotex or the like.

Darren Bell (MCIAT)
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20-08-2010, 11:17 AM
Post: #4
RE: Multi-foil insulation
Sketch - I read somewhere that it depends on whether you are specifying warm roof detail as to whether it can be twinned with another product.

Perhaps Mr DHA Ltd can shed light - although I know his expertise lies with industrial roofing he's a whizz with all things roof-related Wink

Got to confess I'm a bit worried - this forum's been a bit quiet without him for a few days... Confused
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20-08-2010, 04:29 PM
Post: #5
RE: Multi-foil insulation
One of many, TLX holds BBA certification:
http://www.webdynamics.co.uk/images/TLXR...%202-9.pdf

Dr R D Saunders MBEng, BEng(Hons), PhD
Developer of G-Calc 2010 - Part G Calculation software
Building Regulation Consultant and Senior BCO
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20-08-2010, 05:27 PM
Post: #6
RE: Multi-foil insulation
We did a couple of jobs using tri-iso as the building control department were allowing it (although other local councils were not).

As far as installing it goes, it is a piece of cake, takes no time at all and quality control can be maintained better than trying to scribe rigid insulation in between wibbly/wobbly rafters on a 200 year old barn. Service penetrations can be made and sealed easily and the waste fills a bin bag not a skip !.

My understanding of the situation was that the material didn't meet the BS "hot box test" that measures the heat loss through an insulated box (so therefore no BBA cert), however the manufacturers had used the product in scandinavia on actual buildings and had compared fuel costs against properties using this type of insulation and the results were favourable.

I had intended to go past one of the jobs we used it on on a frosty day just to see if the frost stayed on the slates (which to a layman like me would suggest it was doing its job), but I never got round to it, however, no one has rung up complaining that their building is cold !!.

This, obviously, has no scientific basis, but is just my opinion as an installer.
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20-08-2010, 06:25 PM
Post: #7
RE: Multi-foil insulation
Just for a bit of background why councils don't consider multi-foils without a BBA (or as correctly pointed out above -have not been hot box tested) is based on the following CLG statement

Circular 06/2007 issued by DCLG after the
Judicial Review makes it clear that “ The Department is currently of the view, based both
on international scientific opinion and on scientific evidence commissioned and
published by it , that comparative testing does not provide accurate indications of
thermal performance.”

There is a whole raft of Legal isses behind this which are still ongoing. Until LABC issue a statment to the effect that Tri-iso is acceptable LA's will play it safe and not approve it - generally (however,as pointed out there are a few exceptions).

Dr R D Saunders MBEng, BEng(Hons), PhD
Developer of G-Calc 2010 - Part G Calculation software
Building Regulation Consultant and Senior BCO
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24-08-2010, 09:24 AM
Post: #8
RE: Multi-foil insulation
(23-08-2010 08:06 PM)timpane Wrote:  As far as establishing it proceeds, it is a part of baked cake, takes no time at all and value command can be sustained...

You need to give your Universal Translator a kick, Lieutenant Uhura... Tongue
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15-09-2010, 09:46 AM (This post was last modified: 17-09-2010 05:44 PM by Karloff.)
Post: #9
RE: Multi-foil insulation
Leaving aside the American source (I can't help thinking there must be a spray foam insulation supplier closer to home) isn't that a bit dodgy from a damp POV? I understood foam could seal damp issues behind an impermiable wall, thus accelerating wood rot. I mean, fine if you accept that the roof only has a decade or so of life in it anyway, but otherwise not so much . . .

edit: looks as tho the post I was talking about has gone walkies. . .
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15-09-2010, 06:38 PM
Post: #10
RE: Multi-foil insulation
Major poss roof ventilation probs with spray foam - and how can you quantify the thermal properties? Nor can I recall any such system with a BBA.

Dr R D Saunders MBEng, BEng(Hons), PhD
Developer of G-Calc 2010 - Part G Calculation software
Building Regulation Consultant and Senior BCO
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