I am hiring a structural engineer and permitting this, but I want to educate myself in the next 2 weeks before he can visit.
My attic has standard 2×8 16″ oc spanning 13.5 ft. There is blocking mid-way. Max span for 2×8 is typically 12′, so I’m a bit over. Does the blocking distribute the weight enough to bring the 2×8 up to code for Live loads? I think Virginia requires 40psf for livable area.
It looks like the company that built the house planned to finish the attic for live loads. Full electric was ran including receptacle, they even ran the central vacuum up into the attic. It just needs insulation, drywall, and a minisplit for hvac. The floor has me a bit concerned though. I don’t want to find flex in my floors/ceiling from below and have cracking drywall issues.
I don’t feel any bounce in the floor currently, but that could change over time.
Thank you in advance!
Replies
Tall thin beams / joists will tend to twist when loaded. A twisted beam will not carry the same load as one that is straight. The blocking is there to prevent the joists from twisting.
The span capacity of the joists depends on the material and strength of the lumber. What does the material and grade stamp say?
Looks like the stamp says SPIB No 2. Cant see a species on the stamp.
SPIB is Southern Pine Information Bureau (so probably southern Pine)
http://www.southernpine.com/span-tables/joists-rafters/
https://up.codes/viewer/virginia/irc-2015/chapter/5/floors#5
I am not an authority, but this reads like you can use 30 PSF live load for a bedroom.
span tables are worth looking at.