lay boards

[alan49]

hi where can i get a description or diagram of the position of lay boards in a timber roof , are they something to do with the valley?

 

[Eng33]

They were a new thing to me recently, and explained to me by my structural engineer as a means of joining the new rafters (cut roof) of my extension to the existing rafters where they form the valley. As I understand it, the lay board is a piece of timber typically 38mm x 220mm 'ish, nailed flat on to the existing rafters in the direction of the valley, with the new rafters then nailed to it, once the ends have been mitered accordingly.

 

[alan49]

ah right think i got it ,like lying rafters flat on existing roof to give you an A shape to nail new rafter ends , on old houses always seemed thinner boards thanks think i got it

 

[datarebal]

usually was thiner on old houses... not any more