The Grand Designs world is a magical place where work can be done at a fraction of real world prices (a castle renovation for £700K - including the purchase cost ?????). I have no doubt that the laws of physics work just as differently as the laws of building economics in this place.

I saw that and thought of you all.

So all we need to do is build castles in the sky,
to solve our housing problems.

Biff,
It seems only fitting that having opened and closed the enormous string of postings on this subject in the old forum that you should start a hopefully more conclusive string on the new one...
I must confess that having ploughed my way through many of the expansive and to me increasingly incomprehensible although I'm sure very worthy technical postings from Funcrusher, Fostertom, Martian and Mike George I went off the boil a bit.
However on Friday I attended the Homebuilding and Renovating show at the NEC. A good show, many interesting materials, a few disinterested sales guys, some beautiful wood products and a remarkable number of UFH stands. I plotted my course deliberately to avoid going anywhere near the shiny stuff stand and so keep offthe boil and so after a visit of 5 hours plus felt satisfied with what I'd seen but feeling rather knackered headed for the exit.
Then it happened, temporarily off guard, I walked straight into the other shiny stuff stand that's the "by 'eck" rather than the "Mon Dieu" variety. It was fairly busy so I stood fiddling with an installed demo section of said material. A few feet away from me an older couple were receiving a sales pitch. I was interested to overhear that apparently now the 25mm M/F is equivalent not to 200mm of mineral wool but 270mm. Better than that and in a movement not dissimilar to that of cabin crew indicating the emergency exits the sales person pirouetted around and gestured to a 140mm foil faced slab of PUR on another section of the roof and said that the 25mm M/F was also equivalent to that. Then the other thing happened, there was an audibly loud crack and the sales guy jumped backwards as did I fearing the thunderbolt that must inevitably soon accompany this divine intervention. However it turned out to be nothing more than static and I figured rather than entering into a long dialogue it was a case of "'nuff said" and headed on out

From George,

MULTIFOILS versus TRADITIONAL Insulation

Realize yourself an experimentation to get a real and reliable answer to question of the efficiency of multifoils.

Get the description of this very simple experimentation simulating the conditions encountered under a roof warmed by the sun at http://perso.orange.fr/sudoku.laviron/isolantEnglish

You will be able to compare, yourself, multifoils with classical insulators. You will also understand how, in some countries, some manufacturers indicates that multifoils are equivalent to X centimeters of classical insulators by using experiment which have no relationship with the real conditions encoutered in a house...

No need to argue and/or to develop endless theory or questions. There are a lot of other (very good) experiments made by official organisms or by individuals ; the advantage of this one is that you do it YOUSELF.

Have a good experience at http://perso.orange.fr/sudoku.laviron/isolantEnglish

Hi all,

Great couple of debates going there regarding the mutlfoil insulation, and some superb contributions... although i must admit, after having spent a number of hours on the last thread i skipped, oh about 100 pages and went straight to the end.

Im currently doing a MSc in Environmental and Energy Studies, and am considering doing a thesis based around multifoil insulation. I'm looking at a number of angles, one of them being some Life Cycle Assessments on the material. Do any of you guys, (Biff, Keith etc) who have been knocking around this thread for the past while, know of anyone who has taken on such a job? As far as I know the BRE havent, and as yet i havent approached any of the manufacturers. Anyone have any thoughts on whether they'll be receptive to this, and provide me with any manufacturing information they may (or may not) have.

Would also appreciate any thoughts you all may have.

Simon.

Our local council Uttlesford allows the use of multifoil instead of polyurethane . According to a Building Control officer someone (might be BRE) built two identical houses/rooms and insulated one traditionally and one with a multifoil . Then the rooms were tested for heatloss and the multifoil worked as well as the traditional insulation .

All makes of multifoil are currently allowed by Building Control, provided you assume no greater insulation value than the Thinsulex accreditation, which isn't all that good and requires other insulation installed in tandem with it. That's fine by me - something like 80mm of Cellotex carefully fitted gapless between the rafters and multifoil/counterbattens etc either inboard or outboard of that deals with the cold bridging. Calculated result just scrapes thro' Bldg Regs but I'm confident that once the multifoil accreditation mess is sorted out, sometime after August, we'll find that spec actually provides excellent insulation. It's prudent - as conventional insulations perform as expected in steady-state conditions but only a fraction as well under dynamically-varying temperatures; while multifoils do the opposite; this spec covers all eventualities, until we understand multifoils better.

I Live in Rural France and have recently used multifoil between kitchen ceiling and bedroom above the mice love it and after 6 months it looks like a seive whereas rockwool in the adjacent room has not been touched

For the enjoyment of the mice, of course.

Is the article complimentary about them?

Posted By: biffvernon"Until claims can be proven, the potential of more insulation from less material is not borne out."

Does the author explain why "claims *can't* be proven so far? That the testing bodies until recently refused to ratify broadened testing methods that would fairly test multifoils' novel operating principle? Because such broadened testing methods would expose the falacious basis under which conventional insulations have been rated and marketed for decades? That as a result of the multifoil manufacturers' research evidence, such broadened testing was reluctantly accepted in principle by Europe's testing bodies last January and following development of reliably replicable protocols, the new testing methods are due to be launched in August?

What if the claims *are* then proven? Will disbelief still persist? Until then, how many of the otherwise broadminded contributors to this forum will remain convinced that multifoils will fail the tests? Why then is so much new money being pumped into the multifoil companies, almost as if the manufacturers have long since done every conceivable test, to the full satisfaction and enthusiasm of their new backers?

"Until claims can be proven, the potential of more insulation from less material is not borne out" - simply means "wait and see" in normal language.

No, you're welcome Keith.

Posted By: biffvernonLook, it's only a one page article

OK Biff, but I was really countering *your* over-clear "No" to the question "Is the article complimentary about them?".

I don't have an issue with the benefits of reflective foil insulation, BUT I have a major issue with marketing masquerading as science...anytime the non technical person buys without understanding context they have been mislead. As such we are taking the issue to task and have created a full web page; listing articles, excerpts with links to the U.S. Federal Trade Commission and their comments on foil insulation including a publication on a lawsuit against one manufacturer, Canada's NRC/IRC and CMHC with their reports, commentary from The North American Insulation Manufacturers Association and numerous others. We also take to task with three examples from an industry association and a manufacturer both being nebulous with their web text. Feel free to use the links for your own database. http://www.healthyheating.com/Page%2055/Page_55_o_bldg_sys.htm

RBean
Registered Engineering Technologist
Building Construction
Editor Journal of Indoor Environmental Quality

I've heard of them through another forum - all the articles they list are from credible sources and so make for interesting reading. They don't sell any products directly themselves but do represent radiant heating (nothing necessarily wrong with that). As R Bean says, there's nothing wrong with reflective foil insulation, the problem is the marketing claims that, in many cases, are misleading (to say the least in certain cases). A fool and his money are easily parted - people have a propensity to go for solutions that have no basis in science. Just witness the countless number of wonder products based on magnets (curing illness, increasing mpg in cars and all sorts of other rubbish). Sad to say that people pay good money for things that are marketed with pseudo-scientific claims that, of course, are never reproducible in actual testing.

I have used "double bubble" material in a renovation and it does the job I ask of it (and wasn't particularly expensive compared to, say, tri-iso-10 (about 10x less per sq m actually)) but it certainly doesn't have (nor claim) any magical properties.

Paul in Montreal.

There is no magic product for insulation.
Insulation is not just about heat performance is it. What about noise and air filtration, fire and vermin (I prefer our furry friends) amongst other things.
Everything has its place after all. Hope this is a succinct summary.

multifoil insulation is great if;
Used on building fabric exposed to excessive solar gains
refurbishing a space with space limitations which retains existing building fabric and services
the occupants are concerned about emf
Used as one of the methods alongside more conventional and sustainable insulators
it isn't stapled with lots of long steel staples (thermal bridges)
used as part of filtration reduction measures

multifoil insulation is not so great if;
The building is a heritage type airy high thermal mass transpiring buiilding
You want a cavity for services routes
Used in damp locations
Used as an acoustic layer
Poorly installed
sources of ignition/heat are close (orrible gasses are released and it burns like hell)
not overlapped sufficiently at building junctions.

Any others?

regards