Ridge board size - warm roof

[strawberryzoe]

Hi!

We are re-roofing our house shortly and are a little confused about the size of the ridge board required.

We are going for a warm roof construction with the insulation all on top of the joists therefore do not know whether the ridge board needs to extend for the height of the joists plus the insulation, counter battens etc or just the height of the joists?

We are doing a raised tie construction and the rafters are 200mm x 50mm wide with 100mm insulation board on top. The largest ridgeboard dimensions I've seen are 9" by 2" so I'm not sure what we can use if we do have to cover the full depth of the roof construction! Marine ply cut to size?

Any help gratefully appreciated!

cheers
Zoe

 

[noseall]

The ridge board will be largely irrelevant once the rafters are seated and only needs to be as deep as the rafter plumb cut. Just cut the tops of the insulation (roof pitch plumb cut) so they butt together same with the counter-battens.

In most roofs the ridge board is an alignment and fixing aid and not a lot more. Truss rafter roofs don't even have a ridge board.

 

[strawberryzoe]

Thanks Noseall,

that's exactly what I was hoping someone would say - plus I've ordered the right size now!!