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...
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