Rebuilding rotted floor system questions
Got a remodel where one thing turned to another and now I’m working on some wood rot and termite damage. Would appreciate some advice on the repair.
The house is single story from the 50’s and the floor construction was double 2×8 (actual) rim joist with 2×8 (actual) floor joist 24″ oc. This wood rest on hollow 6x8x16 CMU with no sill plate.
The damage is to an area of about 16′ along a load bearing side of the house. Both rims are dust, the ends of the joist are near gone and the subfloor and bottom plate of the wall are gone or near gone as well.
The plan is to replace or sister all of this but would you…
1. Just rebuild like the original design but with PT lumber and flashing?
2. Switch to a modern sill plate design in the repaired area?
3. Fill the CMU’s to anchor the sill in the repaired area?
Replies
Since I assume the rest of the house is original it sounds like you had a leak in this spot that is responsible for the damage. There would be nothing wrong with doing all 3 things in combination but 1 would seem to be all that is necessary. I wouldn't bother with PT except possibly on the rim joists as a PT 2 X 8 might be 1/4" to 1/2" larger in the 8-inch dimension and create more work trying to keep them in the same plane as the old floor.
Definitley try to put something between the joist and the CMU to stop moisture migrtion from masonry to wood. Even if it's just ice and water shield.
Filling the CMU voids will help with cnvection through the block wall and is always a good idea.
Im a big proponent of using Boracare in a situation llike this you mix with water and spray the lumber it will prevent rot and termite damage going forward - its cheap insurance.