Shed roof cabin construction question

[ks2]

Hello
Would likr some advice please.  Putting together plan for a shed roof cabin.  I stuck on how the rafter ties into the top plates.  I can see how cutting a pocket on the shorter wall will do but im stuck on how the taller wall will accept the rafter.
What are your thoughts.

[MountainDon]

The notch in a rafter is called a birdsmouth. Two birdsmouth would be required for a shed roof rafter. Each sits on the top plate.

[Don_P]

It would be stronger with a single, lower, birdsmouth notch. The upper notch being in the end quarter of span is allowed up to 1/4 of rafter depth but "allowed" is not necessarily best practice. That will weaken the rafter. If you do it that way keep the upper notch as minimal as possible.  A stronger way would be to cant the top plate to the rafter angle (which means stud tops cut at an angle and plates ripped at the angle) or rip and install an angled cant strip on top of the plates *.

[RandyRE41]

You'd typically use a birdsmouth at both ends of a shed-roof rafter so each end has a proper seat on the top plate. On the tall wall, it's still the same idea - the rafter gets a plumb cut for the wall line and a seat cut so it bears flat on the plate instead of just hanging off the face of the wall.

A couple things to watch:

• Don't overcut the rafter for the birdsmouth.
• Make sure you have enough bearing on both plates.
• Add the proper hurricane ties / metal connectors to tie the rafters down.
• Check your span, snow load, and local code before finalizing the cuts.

If the geometry gets awkward on the high side, some people use a ledger or dropped beam detail, but for a standard shed roof, two birdsmouth cuts is usually the normal approach.

I'd strongly recommend drawing one rafter full-size on plywood or on the floor first so you can test the fit before cutting the whole set.