Hardwood Floor Repair

Oil soap and all-purpose cleanser remove some stains, especially when the spill is fresh. But it’s impossible to scrub out stains that have soaked into the wood fibers. And sanding only creates a depression in the floor that’s more noticeable than the stain. The only option to repair hardwood floors at this point is to cut out the stained floorboards and install new ones. We replaced a couple of boards from a standard 3/4-in.-thick x 2 1/4-in.-wide oak-strip floor using a drill, circular saw and sharp chisel. To determine the exact width and thickness of the pieces you’ll need, lift up a heat register or threshold and measure the exposed ends of the floorboards. You’ll find hardwood flooring at a local millwork shop, lumberyard or floor-covering store.

Patching Hardwood Floors

Because tongue-and-groove boards are locked in place, removal involves cutting out the middle of each damaged board. The easiest way is to bore a 1-in.-dia. hole through both ends of each damaged board. Then use a circular saw to connect the two holes. Follow these steps to safely make the plunge cuts you need to repair your hardwood floors:

Adjust the depth of cut to the thickness of the floorboards. Plug in the saw and put on eye protection. Pull back the retractable blade guard with your thumb. Then hold the nose of the baseplate on the floorboard and lift up the rear of the saw. Align the blade with the right edge of one of the holes. Make sure the blade isn’t touching the floor, then squeeze the trigger and slowly lower the spinning blade into the board. Grip the saw firmly with both hands and guide it in a straight line until you cut into the right edge of the hole at the opposite end of the board. Move back to the first hole, align the blade with the left edge and cut to the left edge of the second hole. Pry out the middle section with a hammer and chisel. Chop out the remaining edges, being careful not to damage any surrounding boards. The “tongue” piece will be nailed in place, so break it out in small pieces. Then pull out the nails with a hammer or locking pliers. The existing floorboards have a tongue and groove milled on each end and along the edges. Chop off the tongue exposed by the board you just removed so you can slip in the new board.

New Floorboard Installation

Cut a new length of flooring to fit snugly into the space of the old board. It doesn’t matter what kind of saw you use to repair your hardwood floors; just make sure the cuts are perfectly square.

After trimming the board to length, turn it upside down and use a chisel to chop off the lower lip of the grooved edge. That allows it to fit over the protruding tongue of the adjacent floorboard. Test-fit the new piece. If it’s slightly lower than the surrounding floorboards, shim it up with strips of kraft paper. Then remove the board and spread carpenter’s glue on the tongues and grooves of the new and old pieces. Slip the new board into place, protect it with a scrap-wood block and tap it down with a hammer. Cover the board with wax paper, then hold it down overnight with heavy books or weights.

An alternative to gluing: Simply face-nail the board with 6d finishing nails. Bore pilot holes at a slight angle, then drive in the nails. Tap them below the surface with a nailset and fill the holes with wood putty. Lightly sand the entire board smooth, but be careful not to remove too much finish from surrounding boards.

After finding a matching stain color by experimenting on scraps of flooring, stain the boards to match the original floor. Let dry overnight, then apply two coats of clear polyurethane varnish. If the old floor is unstained, just apply the polyurethane.