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Flooring - Silencing Squeaks

Most wood floors develop squeaks at some time or another. Temperature and humidity changes cause various floor parts to shrink and swell at different rates. The result: Squeaks develop where loose boards rub against each other or against loose nails. Modern building codes determine how big the joists must be (typically 2x6 or 2x8), depending on the length they must span. Some older homes, however, were built without benefit of effective codes and may develop sags because the joists are undersized or too widely spaced.

In an older home, the subfloor may be made of 1x planks laid diagonally to the joists; tongue-and-groove softwood strips may be installed over the subfloor. In newer homes, the subflooring may be a single sheet of 3/4-inch plywood, or there may be two layers of 5/8-inch plywood. In other older arrangements, 1x3 “sleepers” are laid across the floor every 12 inches or so. The tongue-and-groove flooring rests on top of the sleepers. If joists below the squeaks are concealed, repair from above. If the joists are exposed below, watch while someone walks on the noisy spot. If the subfloor moves, use shims or cleats to support it. Lack of movement may mean that the finished floor is loose and needs to be pulled down with screws. Strengthen any weak joists by installing bridging.

Anatomy of a floor.Typically a subfloor rests on 2x joists stiffened by bridging or blocking. Underlayment may be used to add rigidity and smoothness for a finished surface, such as carpeting or tile. Tongue-and-groove flooring may rest on a plywood or plank subfloor or on underlayment.

1 .To fix a squeak from above, drill pilot holes. To quiet a loose board from above, nail it to the subfloor. To prevent the wood from splitting, drill pilot holes, angling them as shown.

2. Drive in flooring nails. Drive ringshank nails or finish-head screws. If your flooring was installed with sleepers, there may be a space between the flooring and the subfloor. If so, you must use longer nails. Sink fastener heads below the surface, then fill with wood putty.

If the subfloor moves and you can work from below, insert a shim... Use a tapered shim to tighten a loose subfloor board. Dip the tip of the shim in glue and tap it between the joist and subfloor until it’s snug.

...or install cleats. To tighten a series of boards, force a 2x4 up against the subfloor using a temporary prop. Nail or screw the 2x4 to the joist. Repeat on the other side.

Screw upward. Pull loose finished boards tightly against the subflooring using PA-inch roundhead screws. Drill pilot holes (take care not to drill all the way through the flooring), and use washers so the screws won’t pull through the subfloor.

Improve the bridging. If the bridging isn’t tight between joists, drive in new, larger nails or screws at an angle. If squeaks persist, add steel bridging. Push it tight up against the subfloor, then nail it to the bottom inside of the joists.

Lift a sagging floor. If a floor has a major sag, you may have to add a supporting jack post under it. Break out a section of the basement floor, and pour a 24x24x8-inch concrete pad for the post to sit on. Let the concrete cure for a week. Place the jack post on the pad and set a 4x4 pressure-treated beam, long enough to span several joists, on top of the jack. Jack up the beam until it is snug against the joists, then raise it a quarter turn more. Wait a week and make another quarter turn, continuing this process until the sag is gone. Don’t lift faster, or you may cause structural damage.

Patching Wood Floors

Replacing a section of a finished l\ floor that is interlocked with tongues and grooves requires patience and hard work. If several boards are damaged, take the time to weave in new boards, rather than cutting straight lines at each end; such a patch is unattractive. Use the technique shown here for short sections of boards. If the floorboard is very long and most of the board is in good condition, cut out the damaged section of the flooring with a circular saw. Set the saw to a depth exactly equal to the thickness of the finished flooring. Cut as far as possible without piercing adjacent flooring; complete the cut by chiseling, then pry out the damaged section.

Finding Replacement Boards - New tongue-and-groove flooring is expensive, and it may not match the old flooring in appearance. Also new flooring strips have to be sanded and stained to match the existing floor—a difficult job. The solution is to find pieces from elsewhere in the house. Pry out boards from a closet, or from under carpeting. Get more than you need at present so you can have them on hand for later repairs. Fill the resulting voids with plywood.

1. Drill holes in the boards. Using a spade or Forstner bit, bore holes across the width of the board at the ends and in the middle. Drill only through the flooring board; don’t damage the subfloor.

2. Split the board with a chisel. Use a wood chisel to split the board lengthwise between the drilled holes.

3. Pry out the damaged board. Slip a flat pry bar into a split. Place a scrap of wood under the bar to protect the good flooring. Pry out the split pieces from the middle, then pry out the rest of the board. Also pry out any little slivers left under the tongue of the adjacent board.

4. Pull out old nails. Using a claw hammer, pull out any old nails that remain in the subfloor. Use a scrap of wood to protect the flooring.

5. Cut new boards. Use a miter box or a power miter saw to cut new pieces to length. If you are replacing more than one piece, see that adjacent joints are offset at least 2 inches. Cut pieces to fit well but not too tightly.

6. Modify the last board. Prepare the replacement board (or the last board to be placed when repairing a section of flooring) by turning it over and chiseling away part of its groove. Note how the boards will interlock.

7. Install replacement board(s). Test-fit the replacement piece. If you are replacing more than one board, slip the groove of each new piece into the tongue of the adjacent board and tap it in place. Bore pilot holes and angle-nail each piece through the tongue every 12 inches or so before installing the next piece.

8. Glue the board in place. Apply flooring adhesive to the subfloor, tongue, and half-groove of the replacement piece (or the last piece when repairing a section), then tap it into place. Use a scrap of wood to protect the flooring surface as you tap.

What Caused the Damage? If only a few boards are damaged due to heavy scratching, a simple repair will solve the problem. Other types of damage may be more serious. If boards have tunnels running through them on the inside, termites or carpenter ants are the likely culprits. Call an exterminator. If more than a few boards are cracked, the subflooring may be weak.

Removing scratches. Remove surface cuts or scratches with steel wool and a solvent, such as mineral spirits. Rub with the grain, rinse, and refinish. For deeper cuts, sand with the grain and work in wood filler with a brush. Let the filler set overnight, sand with the grain, and refinish.

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