Found out my joist spans were way off after reading the IRC code book

I was laying out a deck last month for a customer in Austin and pulled out my old span tables. Out of curiosity I grabbed a 2021 IRC code book from a buddy and compared. Turns out the spans I had been using for years were for a lower grade lumber than what I actually buy. I was overbuilding everything by about 2 feet on each span. Has anyone else discovered they've been using wrong numbers from old charts?

2 comments

2 Comments

markm2716d ago

Tbh I ran into this exact mess like two years ago. I was using spans from a 2009 IRC handout that my old supplier gave me and it turned out I was off by almost 18 inches on some 2x8s. Best thing I did was tape a current span chart right inside my truck toolbox and write the date on it with a sharpie. Also I started double checking the grade stamp on the lumber before I even load it because the yards around here mix SYP and Douglas fir and they span completely different. If you don't already have a PDF of the current tables on your phone you're just asking for trouble.

seth_carr16d ago

Got a buddy who runs a framing crew and he found out he was using 2012 spans for three years cause the old foreman never updated his binder. He said his decks were way overengineered but at least nobody got hurt.