Birdmouth depth

[Sonnypaul]

Evening all.

Sorry but I have another question,

for example when I cut my rafters , let's say 6x2, I always cut 1/3 of the seat cut, so roughly 50mm,

My question is birdmouthing the top of the rafter, is it common practise to take out 50mm like the bottom seat cut or just take out 1 inch?

Cheers

Sonny

 

[ree]

Your HAP (height above plate) is typically 2/3 of the plumb cut.

When marking out, carpenters typically reduce the plumb cut at the ridge by 3/4" (half the thickness of a two-by ridge).

Birdsmouthing the plumb cut at the ridge is only done for custom reasons.