I'm in the midst of a bathroom remodel on my 1910 house, thanks to
everyone for their responses to my previous queries. I had to repair
some water damage to the subfloor, and before I cover it up with 3/8"
underlayment for natural linoleum, I have a couple questions.
The original subfloor is 7/8" thick tongue and groove 1x4s, and my
floor joists are 16" on center. I found some 7/8" thick plywood and
made my repairs by cutting back the damaged areas of the subfloor to
the midline of the joists. So:
1) What sort of support at the butt seams perpendicular to the joists
is appropriate? I put blocking between the joists on the boundary
of the largest repair, but that was a a fair amount of trouble.
For the other areas, should I attach some strapping to the
underside of the new and old subfloor? E.g. some 1/2" plywood 4"
wide parallel to the seam, nailed from below with 3d nails.
2) In a few places I didn't makes my cuts perfectly straight, and as a
results there are gaps at the seams of up to 1/8" where I can see
light from the crawl space. Maybe I'm being picky, but I'd like to
fill these gaps. What is an appropriate product to use? I thought
of the expanding urethane foam gap sealer, but I'd prefer something
that expands less and is heftier.