The Magic of a Home With Wooden Floors : Interiors: There are a number of choices in the type of woods available when installing floors, many of them are prefinished.

Each year, manufacturers introduce new, improved types of man-made flooring, all perfectly uniform. But wood remains a universal favorite for its durability and the timeless, matchless charm of its natural irregularities.

A tree trunk is ringed because the large, soft cells of its rapid springtime growth contrast with the dark, dense cells of its slower summer growth. Cellular structure determines the density, direction, color and pattern of each tree’s grain.

Today, most flooring is made from logs cheaply slash-cut with circular band saws. A century ago, more flooring was sawed at an angle. This costlier method produces elaborately patterned edge-grain on two faces, revealing the full beauty of the wood.

Because moisture makes it swell and warp, raw lumber must be dried in an artificially heated kiln that evaporates three-fourths of the wood’s sap and cellular fluid. Another 10% is forced from cell walls, shrinking boards across the grain to create hard, strong, light flooring.

Such softwoods as pine, fir and redwood are often used for Colonial or rustic plank floors with beveled edge to simulate cracks and walnut plugs to simulate antique pegs. Budget-minded remodelers sometimes floor older homes with 1-by-6-inch tongued-and-grooved pine roofing boards secured by quaint, old-fashioned, oblong-headed cut nails.

However, as softwoods are less wear-resistant because their cells are less dense, hardwood strips far outsell them. In greatest demand are 3/4-by-2 1/4-inch oak strips of random length, installed at zigzag intervals or in a herringbone pattern. For snug fit, each strip is milled with a projecting tongue on one side and a groove on the other. Nails driven through tongues are hidden by grooves.

Experts differ as to whether ends should be tongued-and-grooved. Some contend that square-edged strips with interlocking sides lie just as flat. Others insist they squeak. According to Jim Martin of Malibu Lumber, “the tighter the fit, the stronger the floor.”

Square-edged strips require face-nailing and “may throw off stability,” warns Jeff Brotman of Virginia Hardwood, “because boards want to move as much as they can.”

Parquet flooring is another popular wood floor. Block parquets are solid, unfinished, tongued-and-grooved squares composed of hardwood pieces splined together to form a decorative mosaic.

Oak is, again, the most popular wood, 12-by-12-inch the most popular size, alternating cross-matched strips the most popular pattern. However, blocks from 4-by-4 inches to 4-by-4 feet are made in a dazzling array of tones and woods, forming intricate patterns copied from palaces throughout the world.

Laminated parquets are cheaper squares of thin board, bonded together like plywood, sold by floor-covering dealers. They are set into mastic, much like resilient tiles. Todd Hamar of Galleher Hardwood says, “Laminates are not on a par with block parquets, but they come in attractive patterns and, unlike blocks, they can be installed by do-it-yourselfers.”

In his book, “Hardwood Flooring,” expert Dan Ramsey cautions homeowners to buy only from reputable dealers. He adds that, if buyers tell dealers they are shopping around for discounted flooring, most retailers “will either work out some type of discount or . . . suggest when that discount will be available.”

About half of America’s strip flooring is sold prefinished, a boon for non-professional installers. Prefinished floors are virtually maintenance-free.

Renovators are advised to scratch a coin against an old, discolored floor. If the finish doesn’t flake off, it is probably penetrating seal, which can be restored without sanding. Sometimes worn, dingy floors merely need a wax-stripper, a new coat of linseed oil, a treatment with turpentine-soaked steel wool to remove old shellac or a liquid varnish remover and a light sanding.

Unfinished and ruined floors require a great deal more work and are best left to professionals. Mistakes in installation and finishing are apt to cost far more than the fee charged by a professional who knows how to match obsolete patterns, protect and beautify wood, make new floors look antique and old floors look new.

Once the floor has been installed or restored to its original luster, it should never be washed or wet-mopped. Scrubbing rots wood. However impervious the finish, water can seep between boards to stain and warp them. All the floor needs is vacuuming or dust-mopping, an occasional buff to remove heel marks and rewaxing once or twice a year.

DAMAGE CONTROL

Buy good flooring.

Carefully inspect floorboards before accepting delivery.

If lumber is stored outdoors, protect it from dampness.

Acclimate new flooring by storing it two to three days in the room where it will be installed.

Do all necessary painting before installing the floor.

Never install flooring until all interior concrete is dry.

Flooring over a cement slab requires special protection and expert advice.

Never install wood floors in a damp basement or one susceptible to flooding.

When estimating cost, remember that quoted lumber dimensions are less than actual size (a 2-by-4 measures 1 1/2 by 3 1/2 inches). Dan Ramsey’s rule of thumb: actual board footage equals number of pieces by thickness by width by length divided by 12.

Insulate floors over furnaces and heating ducts to prevent future cracks.

Insulate to soundproof upstairs floors.

When planning floors, never assume walls are straight. They seldom are.

For a professional look, frame obstacles, such as hearths and pillars, with mitered molding.

Save short flooring strips for doorways and closets.

To avoid hollows, never let a turned-on drum sander touch the ground unless it is moving.

Dust thoroughly after each sanding.

When applying finish, always allow recommended drying time between coats.

If a damaged spot cannot be invisibly patched, refinish the entire floorboard.

When moving heavy furniture, slide it along the floor on a scrap of blanket or carpeting.

Rubber, plastic and foam-backed mats may discolor floors.

Put cups under metal furniture casters.

If humidity exceeds 50%, ventilate rooms to keep floorboards from swelling.

In very cold or dry weather, humidify rooms to keep floorboards from shrinking.

In rainy weather, close windows, protect exterior doorways, repair leaks and don’t track water across the floor.

FLOOR REPAIR

For fine lines and cracks in hardwood: humidify room.

For cracks between softwood planks: clean out and pack with hemp rope or a wood glue-and-sawdust paste. (plastic fillers shrink.) Span very wide cracks with wood strips. Sand, stain and rewax.

For “bouncy” floors: check beneath house for undersized joists. Hire a professional to stabilize or augment them.

For a squeaky floorboard: for wet weather squeak, soak with liquid wax. Or pour talcum powder or powdered graphite between boards. For persistent squeak, drive triangular glaziers’ points between boards. Tamp down with a putty knife. Or countersink 2-inch finishing nails through both ends of board, putty nail holes, sand and wax.

For creaking floors: see whether nails holding subfloor to joists have loosened. If so, drive wedge between joist and loose subfloor board. If several boards are loose, nail a strip of wood across them and secure it to joist.

For a loose board in the finish floor: countersink 2-inch finishing nails with a nail punch, angling them into subfloor. Putty, sand and stain nail holes. Rewax.

For warped, bulging finish floorboards: cover with heavy paper and a plank. Tap plank sharply with a hammer, taking care not to split tongued-and-grooved edges.

For sagging or inward-sloping floors: see if girders or joists have been undermined by rot or termites. Fumigate if necessary. Raise gradually, a few turns per day, with horizontal timbers supported by concrete-footed jack posts or screw-jacks and vertical timbers.

For outward-sloping floors: raise gradually with jack posts beneath outer edges.

For old floors at different levels in different rooms: install threshholds to mask discrepancies.

To replace damaged floorboards: hire a professional.

To match a few obsolete floorboards: steal them from an inconspicuous area, such as a closet.

To duplicate a roomful of obsolete floorboards: ask a professional to find the same type of lumber and “age” it to match.

To replace a damaged parquet square: check to see if it is screwed as well as glued. Remove. Scrape off old mastic. Glue in new square.

To repair loose strips in a parquet block: find and eliminate the dampness that loosened them. Reglue.

To replace a missing piece of parquetry: trim jagged edges. Scrape out old mastic. Outline cavity on tracing paper. Darken back of paper with soft pencil. Find a similar strip of wood, making sure grain goes the right way. Press tracing paper on wood, shaded side down. Re-outline shape on wood. Cut out with utility knife. Sand underside to proper thickness. Stain if necessary. Glue in. Replicate dark outline with felt pen.

For swollen veneer: cover with cardboard. Press with a hot iron, bearing down hard. Leave a heavy weight on cardboard for 24 hours.

For dents: cover with a damp cloth. Steam-iron.

For scratches: use filler, then wax. Or buy a touch-up kit from flooring dealer.

For worm holes: with an oilcan, squirt commercial wood worm solution into holes. Let stand 24 hours. Wipe off excess. Patch holes with filler. Sand and wax.

STAIN REMOVAL

Alcohol spots: rub with wax, silver polish, boiled linseed oil or a cloth lightly dampened with ammonia.

Bloodstains: rub with wax-stripper. Rewax.

Chewing gum, candle wax and crayon: apply a plastic bag filled with ice cubes. Leave on until substance is brittle enough to crumble. Wax stripper or cleaning fluid poured around the area, not on it, may loosen substance.

Cigarette burns: for shallow burns, rub lightly with fine steel wool dampened with soap and water. Wipe with damp cloth. Dry thoroughly. For deep burns, carefully sand away, fill indentation, fine-sand smooth and rewax.

Dark spots, ink stains and pet or diaper stains: if fresh, wash off and bleach with lemon juice on a cotton pad. If old, scrub spot and surrounding area with No. 1 steel wool moistened with floor cleaner. Pour on vinegar. Leave three to four hours. If spot remains, carefully pour on household bleach. Leave two hours. If spot remains, fine-sand, feathering into surrounding area. Rewax and buff. If spot remains, bleach with 1 ounce oxalic acid in 1 quart water. Wear gloves. It is toxic. Let stand one hour. Sponge with clean water. Repeat if necessary. If spot remains, sand with 00 paper and feather new finish into surrounding area. Rub lightly with 00 steel wool. Apply a second coat. Dry and rewax.

Dried milk or food: rub with damp cloth. Dry. Rewax.

Heel and caster marks: rub lightly with fine steel wool moistened with floor cleaner. Wipe dry. Polish.

Mold or mildew: ventilate room. Rub with a good floor cleaner or cleaning fluid.

Oil and grease: rub with strong kitchen soap. Or cover with white tissue paper and press with a hot iron to soak up stain. Or rub with lighter fluid. Or cover with a cotton pad saturated in hydrogen peroxide and top with another pad saturated in household ammonia. Repeat until stain is gone. Then clean, dry and rewax.

Standing water stains: rub with 00 steel wool and rewax. Or fine-sand, then rub with No. 1 steel wool moistened with floor cleaner or mineral spirits. Let dry. Refinish, feathering into surrounding area. Rewax.