aesthetic reasons, I would like to run 3/4x3-inch oak strip
flooring parallel to the floor joists, instead of perpendicular
as is typical. Is there any reason I can’t do it? The
subfloor is 3/4-inch tongue-and-groove plywood.
Howard Brickman responds: If the subfloor is stiff enough,
there is no reason why solid nail-down strip flooring
can’t be run parallel to the joists. First, renail the
existing plywood subfloor, so that the old nails are tight, and
add new nails to achieve a maximum nail spacing of 6
Where floor joists are spaced 16 inches on-center, whether
or not a 3/4-inch plywood subfloor is adequate for this type of
installation is a judgment call. Some plywood subfloors deflect
more than others. If the plywood feels stiff, you will probably
be okay. If you can feel some deflection, you have two options.
If raising the floor height is not a problem, you can install a
layer of 1/2-inch plywood over the existing 3/4-inch plywood.
The other option — assuming you have access to the open
joists from below — is to install 2x4 blocking between
the joists, 24 inches on-center. Once the blocking is
toe-nailed in place, it should also be fastened from above with
screws through the plywood.
In the unlikely event that the existing floor joists are
spaced 12 inches on-center, your 3/4-inch plywood subfloor is
certainly adequate, and you should have no problems.