By Bernard Gladstone
Published: December 14, 1986

A wood floor that makes squeaking or creaking noises is seldom an indication of a serious maintenance problem. But it can be very annoying — and the problem will rarely go away by itself.

In fact, in most cases, the condition will only get worse if nothing is done.

Before a do-it-yourself can do anything about the problem, it is essential to understand what causes the noises. In almost every case the problem is due to loose floorboards or loose subflooring under the finished flooring. These boards, or sheets of plywood, tend to move up and down slightly whenever someone steps on them or walks across that wood floor. The edge of one board tends to rub against the next board, causing creaking or squeaking.

In some cases — for example, when there is only plywood subflooring to contend with — the noise is due to the wood’s rubbing against nails that haave worked loose or pulled part way out. As the plywood, or one of the floor boards, moves up and down, it rubs against the loose nail — again causing noise.

There are various reasons why flooring boards walk loose. One of the most common is warping or buckling of the wood joists or beams under the flooring. Another reason is that the wrong kind of nails may have been used — nails that were not long enough or heavy enough, or nails that do not grip the way they should. It is also possible that not enough nails were used to hold the boards securely.

Still another reason that nails loosen is buckling of the floorboards. However, in most cases where floorboards have buckled, it usually means that the flooring was not properly nailed down in the first place, or that a poor quality of flooring material was used. Failure to provide adequate clearance around the edges of the room, to allow for normal expansion later on, can also cause floors to buckle.

The most common situation is when squeaking noises occur in a tongue-and-groove floor like the one in the drawing. The boards actually buckle or raise up slightly along the joints where the tongue edge of one board fits into the grooved edge of the next one. Often the squeak can be temporarily silenced by squirting powdered graphite or talcum powder into the joint. This lubricates the edges and the joint, but only temporarily. The noise will return when the lubricant wears off.

To permanently cure the problem, the loose boards must be fastened down so that they can no longer move. This is usually accomplished by driving in nails as shown here. For lasting results, the nails must go through both the finished flooring and the subflooring, and then continue on into one of the joists underneath. However, when this is not possible it is important to make sure the nails at least go through the flooring and down into solid wood in the subflooring — not just into a crack or joint that will provide little or no holding power.

Before starting to nail any boards, make sure you know which ones are actually causing the problem. Have someone walk slowly back and forth across the room in each direction while you listen carefully. Mark the boards that squeak or seem loose when they are stepped on, then drill small pilot holes through the flooring for each nail, to avoid splitting the wood and to minimize the likelihood of bending nails.

Use nails at least one and a half inches long if you are only going through into the subflooring, but use nails two and a half or three inches long if you anticipate nailing into a floor joist. For maximum holding power, nails should be driven in at an angle of about 45 degres, as shown in the drawing. Position nails so they will go through the tongue edge of one board and one lip on the grooved edge of the other board. Alternating the direction of nails so that every other one slants in the opposite direction, as ilustrated, will not only greatly increase holding power, but also will practically eliminate chances of these nails ever pulling loose.

When the creaky floor is over an unfinished basement or crawl space, so that the flooring is accessible from below, it is sometimes neater and more effective to solve the problem by working from underneath. After locating the area where boards mmove up and down — listening from below while someone walks around on the floor — drive wood wedges between the flooring and the joists, as shown here, wherever there is movement. Any tapered piece of wood can be used, but wood shingles are particulGrly useful for this purpose. Coat the wedge with glue before driving it in, and use more than one thickness if a single thickness does not seem to be enough to stop all movement.

Another method sometimes used is to nail a short length of 2-by-4 against the side of the joist, instead of driving a wedge in on top of the joist. Coat the top edge of this 2-by-4 block with glue, then press it hard up against the underside of the flooring. While pressing upward in this manner, nail it against the side of the joist to hold it in place. Like the wedge method described above, this will support the loose flooring so it cannot move up and down when stepped upon. Answering the Mail

Q. My house has two porches, one in front and one in back. My husband always used to paint them with an oil-based paint that dried with a shine. The last time the porches needed painting, I called in a painter who used a water-based acrylic paint that dried to a dull finish. It looks awful because you can see every speck of dirt, and it tends to attract dust and dirt when walked on.

I tried cleaning with soap and water, but it doesn’t work. In addition, the paint is beginning to flake off in spots. The painter has offered to repaint with an oil-base paint, but I know something should be done to the floor first. What preparation do you recommend? -A.S. Jamaica, Queens.

A. If a latex (water-thinned) paint was applied over a glossy surface, there may be a continuing problem with flaking or peeling. The gloss should have been dulled by sanding before the new paint was applied. Your best bet now is to sand the loose or flaking paint off before applying a fresh coat of oil paint — the more of the old paint you can remove the better.

If you don’t get all the old paint off, make sure you at least sand and scrape enough to remove all paint that is loose or flaking, and be certain you have dulled the gloss on any of the old paint that shows through. Then wash the surface thoroughly and allow it to dry for at least one full day before applying the first coat of oil base deck enamel.

Q. I have moss on my outside concret esteps and this is creating a slippery condition that is also dangerous. There is a large tree over these steps. Can you tell me what I can do to remove this green growth? — B.F.P. Larchmont, N.Y.

A. You can wash the moss off with a fungicide sold for this purpose. In many garden supply stores and pool supply dealers. Or you can use a solution of one part fresh liquid laundry bleach mixed with about four parts of water. Scrub this on and let it soak on the surface for several minutes, then rinse off with lots of plain water. To help prevent the moss from growing back, it would help if the large tree could be pruned to allow more sunlight through, and you might try coating the concrete steps with masonry sealer or paint.

Questions about home repair should be addressed to Bernard Gladstone, The New York Times, 229 West 43rd Street, New York, N.Y. 10036. Questions of general interest will be answered in this column; upublished letters cannot be answered individually.

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