Appreciation post: my neighbor's offhand comment about my shed saved me 3 hours

I was framing out a lean-to on the side of my garage last Saturday. Had it all measured and cut, ready to nail up the rafters. My neighbor Bob walks over, looks at my layout, and says "you know your birdsmouth cuts are gonna sit about an inch high with that pitch, right?" I had my angle finder set for a 4/12 but somehow messed up the transfer. Redid two rafters in 15 minutes instead of tearing apart the whole thing later. Anyone else got a save from a passerby that caught something obvious you missed?

3 comments

3 Comments

craig.olivia5d ago

Actually, that's not quite how birdsmouth cuts work with a 4/12 pitch. The birdsmouth is just a notch cut into the rafter to sit flat on the top plate, it doesn't change the height of the rafter by an inch unless you cut the seat cut wrong. If your rafters were off by an inch, it was likely a problem with your rafter length calculation or your angle transfer from the speed square, not the birdsmouth itself. A good check is to lay out the plumb cut first, then measure down the top of the rafter for the birdsmouth location. Bob was probably right that something was off, but pinning it on the birdsmouth is a common mixup. Glad you caught it before nailing everything up though.

lee.cora5d ago

Honestly, it's just a birdsmouth cut. People overthink this stuff.

angela7285d ago

Wait, wouldn't the plumb cut and the birdsmouth work together to affect the overall fit though? @lee.cora I think you're right that people make it harder than it needs to be, but at the end of the day that little notch can throw your whole rafter off if the depth isn't matched to the ridge height. It's all connected, you mess up one angle and the whole thing sits wrong.