How to Lay Tongue-and-Groove Subflooring
Many older homes have plank subfloors. If you are remodeling and find that some areas of the subfloor are damaged, consider replacing them with new tongue-and-groove boards.
Tongue-and-groove boards interlock, which can make it difficult to repair a small area -- releasing one damaged board would mean releasing all the boards. Instead, use this patch method to replace just the damaged board.
Drill a hole close to one edge of the damaged board, toward the top, and large enough to take the point of a drywall saw.
Insert a drywall saw into the hole and cut all the way down the joint between the boards.
Use a chisel to pry out the damaged section of board.
Cut a new section of board to fit. Saw off the tongue of the new board. You may have to secure it in a work bench to make the cut.
Secure the new board in place, nailing through its face because there is no available tongue for angled blind nailing.
Fill the nail holes with putty then sand when dry. Then paint the board to match the surrounding surface.