Steve writes: Could you tell me if tinfoil vapour barrier is " legally" considered insulation? I bought a house two years ago and just discovered that there wasn?t any insulation in the walls, only this tinfoil stuff. The sellers lawyer claims this is classified as insulation so the seller doesn?t have to come good for fixing the problem. your comments and expertise would be greatly appreciated
Aluminium reflective foil sold as a vapour retarder does have an "official" R-value (but in reality it does more good in Florida than it does in Canada because it is reflecting the hot sun rather than reflecting simple body heat in Canada). Where are you located? In the southern States there are actually products that have foil, air, foil, air, foil -- kind of like an air mattress and they are considered as insulation there for an Air Conditioning climate. In Canada, Qu?bec is the only province I know of that gives an R-value to a reflective foil, but foil alone is far far from meeting any Canadian building codes.
There is another product on the Canadian market that is aluminium foil on both sides of a plastic bubble wrap. This does in fact have a bit of useful R-value ? the reflective values for each of the foils plus a little for the air space - three time a little bit. The catch is that reflective barriers have no officially accepted R-value unless the reflective facing is kept clean and it faces at least 3 / 4 inches of an air space, and that air is not moving. That is a lot of conditions that are rarely all met. In addition, these products are often seriously over marketed, claiming R-values that were never tested and approved by the government standards bodies. Your official reference for legal acceptance of any given product is the CCMC (Canadian Construction Materials Centre) Registry of Product Evaluations that is published every year by the National Research Council of Canada ? this registry is available on the web at http://www.nrc.ca/ccmc.
I am interested in your case, and in your builder and in the lawyer. Give me some more information and we will see if we can take this all further. Where are you located? Exactly what is in the walls? Do you have a brand name or better yet a CCMC Material Evaluations number ? which should be stamped right on the product.
?..to be continued.