Hi Notch, that was what was specified - 90 mm joists and 100 mm rafters. I guess this should have been picked up and clarified at the design stage but doesn't every jobs have these grey areas? And where there are grey areas, there should be a standard of fitness for purpose. A loft that you cant place things on, or that by placing things on damages the insulation seems to me to be not fit for purpose. A side from fitness for purpose, what is the standard of work to be done to. There are some references to complying to Building Regs in the contract (JCT MWD 2011) but where does the manufacturer recommendations fit into it? Also, some of the stuff in the product documentation is not recommendations, for example where they use language like 'must'. They dont usually give reasons, or say what will happen if not followed, so I am wondering if a contractopr can be help to whats said in there, especially when he cannot explain why his approach would be OK to use.
The quote was done in September. I think one of the causes of the supply shortage was a fire in Germany (making PIR but affects all supply) in Oct 16. I don't know how much the prices have risen since September, probably still on their way up?
Were talking about the 90mm Koolthem here. The contractor did buy cheaper stuff, a mixture of Iko Ecotherm, Enertherm and Celotext I think. Those products are all of a similar quality, same r values (.022) and all lower and cheaper than Kooltherm. For the Kooltherm K117 100 mm, the equivalent products are about 40 a sheet, Kooltherm would be 70. I think a lot of the other products are the same stuff, and some merchants say they may substitute depending on availability, but Kingspan is in a different bracket.
