We had a hardwood floor installed in a large room last December, at which
time several "interesting" structural details became apparent:
1) The subfloor is 2x6 tongue and groove douglas fir planks, laid at a 90
degree angle to the joists
2) The joists are 48" on center, and as I recall are mostly built up out of
2x8 or 2x10 (don't remember which)
The floor squeaked like crazy before the job, and I screwed every board down
with one or two deck screws to supplement the nails. This stopped much of
the squeaking, but there are still some "deep squeaks" (more like groans)
that remain. I was unable to pin the source of the squeaking down precisely,
but it seems to be coming from somewhere on top of a post where pieces of a
built-up joist butt together (maybe inside the layers of boards - it's a
tough thing to pinpoint) What is the recommended way to handle such a thing?
Just drive a bunch of screws into the joist members?
Another issue - the floor doesn't feel "solid" on one half of the room - you
can definitely tell you're walking over a crawlspace. I don't know if this
is because of minor deflection that is slightly perceivable, the echo
underneath, or some combination. On the other half, the floor seems very
solid, but the constuction is different; there is a finished room
underneath, and floorboards run the other way (and presumably the joists,
too - but since it's finished, I can't tell). Are there reasonable
retrofittable cross-bracing schemes to be recommended for stiffening up a
floor from underneath?