Firrings are cut through the length of the timber to create a slope when laid on top of roof joists for a flat roof before being covered with osb or ply then finally felt.
Flat roof joist fixings.
To fix the joists and rafters down on to the wall plates they should be toe or skew nailed to the top plate like below.
By way of metal flat roof joist hangers.
Using timber wall plates.
If your plate and ledger are straight and level the you will have a nice flat ceiling.
It takes time experience and equipment which larger merchants often do not have.
We stock only the best bracketry at great prices that will provide the securest fixtures such as.
A cavity closer should be provided to the top of the walls to prevent fire spread and to stop damp air entering the roof space.
Not many merchants cut firrings anymore.
This article covers all manner of flat roofing venting methods and details on how to build a flat garage roof and how to frame a flat roof and also encompasses flat roofs roof decking roof coverings including flat roof felt how to prevent leaks at abutments timber flat roof construction details and parapets and common.
Fix the new joists to the ledger with appropriate timber to timber joist hangers.
Normally i would set the joists out at 400mm on center for the ceiling plasterboard and set them in 50mm from the inside wall.
Set out the ceiling joists onto the wall plates the ceiling joists are installed before the rafters as they will stop the roof spreading and also give something for you to lay planks across to stand on when building the roof.
Stainless steel brackets stainless steel fixings steel strapping heavy duty joist hangers and square plate washers.
Create timber frame structures with toolstation s range of nail plates including galvanised nail plates and safe metal fixing plates.
Where a new flat roof abuts an existing external wall the joists can be hung on metal joist hangers which are fixed to a horizontal timber plate wall bolted to the wall.