Hi,

I had a plan for a cold roof on the dormer I'm building - here isn't enough headroom for a warm roof. The original plan was to have 50mm air space above 120mm Celotex in the roof space. In haste, I went a bit off plan and fitted the rafters into joist hangers at the outside end, rather than supporting them on a beam. The way I've now installed the rafters means the ends are closed.

The building inspector pointed out my error, and my heart sank. I'd expected I'd be required to make a substantial re-build. However, he just said to make sure the vapour barrier was airtight and call it a sealed roof. I understand what he's suggesting, and I know the importance of sealing the roof really well (no lighting in the ceiling) but I imagine that even with the greatest care, there'd be an air leak somewhere, and the space would eventually become damp and there'd be no way for it to dry out. So even though I have building regs approval, I'm hesitant to go down that route.

Any suggestions that don't involve reinstalling the rafters (I've temporarily fitted OSB on top of the rafters to give me a dry workspace while I sort out walls and floors)? I can't drill holes in the supporting beam, as this would compromise its strength, and anyway wouldn't provide anything like the planned for air flow.

Thanks,

John

I can do a bit of door stop. Thanks.