We'd like to replace the carpet in a bedroom with solid hardwood flooring. (The wood would probably be 4″ rift and quartered white oak.) Our house was built in 1979, but has solid 1×12 (yes, they measure a little over 11 inches) planks laid on the diagonal as a subfloor; the planks actually measure closer to 13/16″ thick (20.5 mm) and the joists are 2×10s installed 16″ OC. (There currently is ½″ particle board underlayment over the planks, which is going to have be removed. Thankfully, it's only nailed down!) They are in very good condition and very flat with no cupping.
My question is should we nail/staple the 3/4″ hardwood directly to the original subfloor, perpendicular to the joists? The NWFA guidelines mention that this is allowable, but only for plank subfloors with boards that are not wider than 6″. Would we have to add 3/8", 1/2", etc... plywood over the planks for stability? Is CDX plywood sufficient for that purpose? (I used 5/8″ AC or BC for a tile job in the bathroom, if I remember correctly.)
What would you recommend if the boards were nailed in a herringbone pattern? My concern is that whereas half of the boards would be perpendicular to the diagonal planks, the other half would be parallel.
My question is should we nail/staple the 3/4″ hardwood directly to the original subfloor, perpendicular to the joists? The NWFA guidelines mention that this is allowable, but only for plank subfloors with boards that are not wider than 6″. Would we have to add 3/8", 1/2", etc... plywood over the planks for stability? Is CDX plywood sufficient for that purpose? (I used 5/8″ AC or BC for a tile job in the bathroom, if I remember correctly.)
What would you recommend if the boards were nailed in a herringbone pattern? My concern is that whereas half of the boards would be perpendicular to the diagonal planks, the other half would be parallel.
