Multi Foil Insulation - The Uk's View

No6

I came across this doing a bit of research into part L in the UK, for all you assessors specifiers and certifiers if you need a bit of solid background for a client on why their insulation dons't comply, Its quite long but the last page or two pretty much sums it up!!

http://www.communities.gov.uk/documents/planningandbuilding/pdf/1745517.pdf

BryanF

thanks No6
great link, I think this sums it up:

17. The Council believes that methods for measuring the thermal performance of materials and products should be British Standard tests based on Standardised European Norms or tests to a European Technical Approval (ETA) standard. The values for the thermal performance of insulating products provided by these tests enable the accurate assessment of conformity with the guidance given in Approved Documents L when use of the products is proposed. The Council asserts that comparative testing used by many multi-foil manufacturers to indicate the performance of their product is not covered by any national or European standard, and consequently the results obtained cannot be used to accurately assess conformity with the guidance in the Approved Documents L.
18. The Council concluded that, as the thermal performance of XXXX XXXXXX multi-foil insulation had not been assessed using a test method based on Standardised European Norms or tests to a ETA standard, it was unable to determine whether or not the product's use as proposed would show compliance with Requirement L1(a)(i).

32. Professor Eames therefore calculated that the predicted thermal performance of typical multi-foil material is worse than that of 100mm of mineral wool insulation; and even if made from silver foil and aerogel, it is worse than that of 200mm of mineral wool insulation.

oh, if we only had building control ....

BryanF

I need help here

this stuff does not have a BBA or IAB cert but has a LABC certification, when i contacted them they said they simply check the EU certification which is by a Dutch company BDAKeuringsInsituut to BS EN 12667:2001 (Thermal performance of building materials and products. Determination of thermal resistance by means of guarded hot plate and heat flow meter methods).

as far as I can decipher under this en 12667 a hot box test is used that:

includes the effect of the surfaces on the thermal resistance of adjacent air spaces. These effects will not be allowed for in a normal hot-plate test where the surfaces of the test sample are adjacent to the hot and cold plates of the apparatus. Also, if the surface of the material is not flat, as is often the case with multi-foil insulation products, parts of the surface will be in contact with the hot and cold plates while other parts will have air pockets between the product surface and the surface of the hot and cold plates. This combination of direct contact areas and areas with air pockets make any test result difficult to interpret and apply to the product and its intended application.

The thermal performance of multi-foil insulation. T I Ward & S M Doran. BRE, Scottish Enterprise Technology Park, East Kilbride, Glasgow, G75 0RZ . July 2005

this study sort of suggests to me that unless the material is locked in an air-tight cavity space, then its not going to give the values its states..

their supposed 'BBA cert 09/4640' http://www.bbacerts.co.uk/PDF/4640PS2i1.pdf but its just for the foil sheet!

builders are using this by stuff by the ton!!! at 20€ for the product per msq!!!

I appreciate that these products have reflective heat properties but in our climate what good are they?

they are also being used in areas where a Vapour barrier should be used on the inner side and a breathable membrane on the outside (or at least ventilation instead)- these products aren't breathable! - "they provide significant resistance to the passage of water vapour" (BBA cert 09/4640 above)

I would really like to delve deeper into what can be done about their use in Irish homes..

BryanF

as were in the BER section, how many of you guys would accept this product for BER compliance?

No6

I wouldn't!!

sydthebeat

BryanF wrote: »

as were in the BER section, how many of you guys would accept this product for BER compliance?

not without adequate additional insulation to bring u values up to regs....

BryanF

sydthebeat wrote: »

not without adequate additional insulation to bring u values up to regs....

when you say additional insulation, what do you mean?

sydthebeat

BryanF wrote: »

when you say additional insulation, what do you mean?

i always tell client that i consider multifoils as vapour barriers that have good insulating properties. They still need additional insulation to meet regs

see this BBA cert

it includes values to be entered into u value calculations which allow you to specify what additional insulation you need. It also includes a spec of how to install the foil with other insulations.

In my experience however, when clients understand that these products are NOT an alternative to insulation, and are simply expensive vapour barriers, they quickly resort to a more traditional insulation spec.

woody1

got stung with this stuff myself ! doh !
shouldnt have but made a stupid decision that it would save time and i believed the claims / cert that it had at the time.. it wasnt long out at that stage, that alone shoudlve made me stay away
all i can say is its worse than useless, mercifully the entire roof isnt done in it, about 30 - 40% id say.. id love to figure out a way to improve things without ripping off the ceiling and starting again but i dont think it can be done..
but i did get to tell a rep for it in the middle of a demo / pitch he was doing with a good few other architects and technicians that i had it and thought it was crap..so a bit of payback at least.. he did refer to problems they were having getting certified alrite, but he was saying that this material couldnt be tested in the way that the british standards wanted it to be tested, and that therefore the problem was more with the b.s. not understanding how the material worked than a problem with the material itself ..
all i can say is steer clear of it ..

BryanF

woodie, I'm worn out with it:(... here's where I've gotten too: the foil insulation 'system' in the OP must be installed as per their BDA certification which I'm told is the same as BBA or IAB

this product must be basically sandwiched in a cavity build up where there is no air movement and used on the internal side of the required insulation as a sort of Vapour impermeable layer that must be taped and sealed using their tape. so whether I believe their claims or not, in the situations where I have seen it proposed/installed, its not being installed or spec'd/ detailed correctly..

sydthebeat

BryanF wrote: »

........, its not being installed or spec'd/ detailed correctly..

... thus rendering any certification invalid.....

... thus meaning that the product must be ignored when determining compliance with building regulations and BER certification.

woody1

i think it was operating off a european cert when i got it and it was claiming to be sufficient on its own to meet the required u-value.. too good to be true comes to mind.. it was obvious enough that it would have to be taped and sealed fairly well, but i doubt it actualy was, even if it was , its now clear that the system needs additional insulation to meet the required u-values, which isnt what they were claiming at the time..
for my own house i could probably retrofit an insulated slab over the existing ceiling, the affected rooms are a hot press , wardrobe, hall , and a bedroom with a very high sloping ceiling, but even if it did improve the insulation situation..im not sure if sandwiching the existing ceiling between 2 layers of insulation is a good idea.. and im really not sure if i want to go to that kind of level of work / expense to rectify things..
probably an inch of insulation is most likely not going to be any more effective than whats there at the moment .. !!
getting back to the point.. if you have to use additional insulation with the product..why use it at all.. its main selling point would have been that it did away with cutting and fitting in place rigid insulation, but now you have to do that anyway..