Insulation Requirements

[junglejim01]

Hi, I'm in the process of refurbishing a lean-to extension. Originally there was a false ceiling with no insulation at all. I've pulled all of that out and fitted 50mm Celotex between rafters and 62mm insulated plasterboard under rafters (so another 50mm insulation + the 12mm plasterboard). Total insulation is now 100mm and greatly improved from previously.

I've just had a builder in to look at some work i've asked him to carry out and he's mentioned that the building inspector will be looking for 125mm insulation in the roof space and could ask us to improve what I've done. Is this right? I'm starting to get really annoyed with the regs...if i hadn't done anything the extension would have no insulation yet would be ok! go figure!

Any advice and help very very welcome.
Thanks

 

[grovepark]

It's true I'm afraid, all part of their idea to gradually upgrade the existing housing stock. The regs require it to be brought up to almost current standards, but do allow for reasonableness such as you are loosing headroom or quite a lot of floor space.

Without knowing the exact products you used its hard to advise on what would be needed.

Also have you thought about ventilating the roof above the insulation?