- Q. For 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.
A.Flooring contractor 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 inches.
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.
