Cut a birdsmouth too deep on a rafter and had to sister it on the fly

Working on a shed roof in Austin last month. Measured twice like always but my speed square slipped when I marked the birdsmouth. Cut it about 3/8 inch too deep into the rafter. That thing would have split under snow load. Had to grab a scrap 2x6 and sister it next to the cut, glued and screwed with 3 inch deck screws. Took an extra 45 minutes but the rafter is solid now. Anyone else keep a few extra boards around just for fixing your own screwups?

2 comments

2 Comments

skyler5161mo ago

Big mood. I did the same thing last year on a pergola beam and had to scarf a piece in. Kept that scrap pile fat ever since, it's basically my insurance policy against being a clown with a circular saw.

matthewp521mo ago

Nah, you gotta be careful with that "insurance policy" mindset though. A scrap pile is helpful for small patches but scarfing a joint into a beam under load needs solid engineering, not just whatever's leftover. That fix might hold for a pergola but don't push your luck on anything structural.