Maintaining and Fixing Wood Floors

By Mary Ellen Polson

Part of the charm of an old wood floor lies in its minor imperfections: the familiar creak of a floorboard; a gentle undulation in the hall; the gouge mark so ancient that the scar has a patina. Any older log home can be expected to have floors that squeak, sag or slope, and, in most cases, these flaws aren’t structural. With a little know-how, you can easily silence faulty floorboards and repair minor damage. We’ll also give you tips on what to do about those pesky cracks that open up as the seasons change. When flooring problems are the result of old age, it’s a pretty good bet that conditions have stabilized. (In other words, they probably won’t get worse — at least not while you live there.) You can troubleshoot your floors by talking a walk around the room.

Squeaks, Creaks and Springy Spots

You’re likely to hear problem spots before you see them. A squeak usually means a floorboard isn’t making adequate contact with the supporting joist below. A deeper-sounding creak is probably an indication that the joist is inadequate. Spongy spots can result from either condition. The solution is to reattach loosened boards using a pair of nails driven into the heart of the squeak or by anchoring them with screws.

Gaps Between Boards

Both plank and tongue-and-groove floors can develop unsightly gaps as the floor ages. This is caused by compression shrinkage. During periods of high humidity, a floorboard will expand and compress its neighbors. When dry air returns, the boards shrink, but don’t fully decompress. Since the shrink/swell pattern persists even in the oldest of floors, the best remedy is to do nothing, particularly if the gaps tend to close up during the humid months. If the gaps are especially large or pronounced at certain times of the year, consider the following alternatives.

• For gaps that appear during dry, cold weather, try increasing the humidity level in the house by running a humidifier. This may encourage shrunken boards to expand. Just be careful not to make it too humid, lest you impact your log walls, too.
• Fill gaps with a flexible paste or fiber filler that can adapt to the shrink/swell pattern of the floor. Water and solvent-based fillers are widely available at builders’ supply stores. Homemade remedies include mixing sawdust with a binder such as varnish, shellac or white glue, or hemp rope soaked in linseed oil or glue. The sawdust mixture is simply pressed into the gap; pack the soaked hemp rope into the crack using a large flathead screwdriver or small putty knife. (Apply two layers if the crack is deep.)
• Gun in an elastic caulk that cures to rubber. A flexible marine or silicone caulk should only be applied when the cracks are halfway through their shrink/swell cycle (normally in spring or fall). Carefully mask the edges of the crack to keep the caulk off the floorboards. You may need to partially fill very wide cracks with a pliable backing material, such as cloth or weather-stripping.
• For wide gaps that persist throughout the year, it’s possible to fill them with tapered wood strips. Be aware, though, that introducing new wood into the situation may compound the problem. Glue or toenail the strips with brads to each board, or face-nail them to the joists or subfloor. The repair may need to be hand-planed or sanded to match the level of the floor.

Minor Floorboard Repairs

To replace one or two bad boards, begin by finding replacement wood that closely matches the sound condition of the original flooring. Some tips for matching wood:

• Look for similar species, age, and size (width, depth, and profiling). Candidates should have a similar ring pattern (spaced closely or loosely together). They also should be cut the same way: flat-cut (flat-grain) boards have annual growth rings that run parallel to the face of the board. The rings on rift-cut (and quarter-sawn or vertical grain) flooring are usually vertical to the grain face and are more uniform.
• Unless you have rare or unusually fine flooring, look for sources close to home. A local salvage house or even your own closet or another inconspicuous space may yield the best match.

Replacing a Floorboard

Most antique wood floors are composed of individual (plank) or interlocking (tongue-and-groove) boards laid together. Replacing one bad section on a plank floorboard is a relatively simple repair, but there are some caveats. First, the boards tend to run the full length of the room, so a small patch may stick out like a stubbed toe. Second, there may be no subfloor, so any repair should span at least one joist and share support on another. Fastening a sturdy block of wood, or cleat, next to the joist to support the new board is one method of “sharing.” Before making any repairs, determine whether the floorboards are face-nailed (heads exposed) or blind-nailed (heads concealed between boards, usually driven at an angle). Use the same method for repairs.

Surface Repairs

Minor holes and gouges can be filled with wood putty. To repair a crack in an otherwise sound board, glue down any long splinters, then fill the crack with wood filler or putty.

Treating Stains

Old, stubborn stains are hard to remove once they’ve penetrated deep into the wood. Before breaking out the sander, however, try cleaning them. Some stains, like red wine, may come out with common household white vinegar, especially if they are recent. More persistent stains may come up through the use of a bleaching agent. Before you apply any strong agent, test it in a spot that doesn’t show, and protect yourself against fumes and exposure.

Chlorine

Effective on stains containing aniline dyes and ink. Use common laundry bleach (a weak solution of about 5 percent sodium hypochlorite) or dry swimming-pool chlorine mixed with hot water. Even low concentrations of chlorine can burn the skin and eyes, so wear long rubber gloves, eye protection, and allow for plenty of ventilation.

Oxalic acid

Mixed with warm water and as concentrated as possible, this organic acid removes blue-black water stains, iron stains on oak and lye-blackened wood stains. It’s usually available in dry crystalline form at hardware stores or wood finishing suppliers. Dissolve the crystals in hot water until you get a saturated solution — i.e., the crystals won’t dissolve any more. Oxalic acid is poisonous and should be used with care.

Peroxide

Sold as a caustic solution with a concentration of up to 30 percent, hydrogen peroxide is effective for lightening (aka,“blonding”) woods and last-chance stains. If you’ve been lucky enough to inherit an old wood floor with your classic or historic log home, a little know-how and elbow grease will help you restore it to its former glory.