Hello All,
I’m looking for a validation on a proper repair technique for rotten floor joists. This is a 1940’s era San Francisco area building, a square box of a home if there ever was one, 25′ wide by 50′ length. House consists of a garage/basement on first floor and living quarters on second floor.
The floor joists are 2×16’s every 12 inches that span the whole 25′. Also 4th or 5th joist is doubled up.
Took out the bathroom shower pan, which must have been leaking and 1 of the doubled floor joists are rotted all the way through, the whole 16″. The rot is about 24′ worth of material in length. If it makes any difference, the rot is located within the first 6 feet of the joist, hence within the first third of it.
There is no noticable sag in the building, but after proper precautions are taken, I was thinking of cutting/replacing out the rotted material and then dropping new 2×16 x 10 feet in lengeth on either side and bolting all together.
Any thoughts if this is a sufficient repair? Or is there a better way? Any thoughts on nailing or bolting schedules?
Thanks,
Tark
Replies
I assume you mean the rotten area is 24 inches wide, not 24 feet?
This close to an end it's best if the sister joists can be levered up on the sill on that near end, vs just fastening together. And you want to go as far in the other direction as you can manage -- six feet if at all possible with ten being better.
Yes, I meant 24 inches wide. The rot starts about 4 feet from the sill and 24 inches. My thoughts were to sister on either side, starting from the sill with a 2x16 10 feet in length, hencing overlapping the damage by 4 feet. Hope that makes sense and is sufficient. Tark
If your only 4' past, all the stress is on that section. I'm not an engineer, just a carpenter, but I think I'd like to fly past the rot by more than I've come out. In your case you're out from the sill 6' to clear, so maybe 8' past. I'd say 6' min. Glue and bolt. I don't know if you can get the joists in 12 or 14' lengths.Anyway, the farther the better, short of getting ti engineered.