Max birdsmouth max cut depth?

[epsilonGreedy]

Some say max 1/4 of rafter depth, others say 1/3 and an official sounding site states minimum 1/4 and max of 1/2. My truss designer also added minimum wall plate seat in the cut should be 50% of wall plate width though that was for infill jack rafters along the hip rafter.

 

I Googled for a prior BuildHub question on this 

Edited November 26, 2020 by epsilonGreedy

[PeterW]

Max 1/3rd depth according to building control. 

[Dave Jones]

i believe there is a minimum bearing which the 1/3rd cut cant breach.

 

If you havent ordered pre-made trusses then your structural engineer will have specifed the birdsmouth.