April 2008 has seen Local Authority Building Control issue definitive guidance notes on multi foil insulation to all Building Control Officers.

Of particular relevance is the following:

" ... we are not aware of any multi-foil product currently on the market that can meet the normal roof "U" value requirement of 0.2 when used as a single layer without the need for additional insulation."

Basically, LABC do not accept the multi foil industry claims on R values for their product and will not accept multi foil on its own as meeting  U values under Building Regulations.

This would seem to be the final death nail to multi foil. As an insulation product on its own merits LABC do not deem it a product that can meet Building Regulations. So, should you use it? Not if the requirement is to meet Building Regulations for U values as Building Control Officers will not accept it!

For further information download the LABC Guidance Notes issued in April 2008 to all Building Control Officers and Departments for Compliance with Part L1 and Regulation 7 download here.