dianahayes•23d agoProlific Poster

Found a stat about stair rise tolerance that threw me off

I was looking at the IRC code book last night for a basement stair job I'm starting next week. Turns out the max difference between the tallest and shortest riser on a single flight is only 3/16 of an inch. I always thought it was 1/4 inch like some old timers told me. I found it on page 52 of the 2021 IRC if anyone wants to check. Has anyone else gotten tripped up by a code detail that you thought you knew for sure?

3 comments

3 Comments

emma_dixon7023d ago

@bennett.jana probably never measured a stair stringer in his life. That 3/16 rule will sneak up on you quick. Always double check your cuts before you set them.

emery_white23d ago

Gotta love when the code book humbles you real quick. I once spent a whole afternoon framing a deck with what I thought was the right joist spacing only to find out I was off by half an inch. Felt like a real genius when I had to rip the whole thing apart. That 3/16 rule is brutal though, one bad tread and you're already over.

bennett.jana23d ago

Is it really the code book though, or just bad measuring on your part? Half an inch on joist spacing isn't going to make your deck collapse.

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