Wood Floor Refinishing
Wood floors on joists usually consist of a subfloor, building paper, and a finish flooring of hard or soft wood. In some cases, however, one layer of finish flooring may be applied directly to the joists without subflooring. In the course of time, wood floors may sag or develop cracks, and floor boards may become loose and creak when walked on. Floors may sag if the joists are too light for the length of span; sagging may also occur if there is shrinkage in the wood girder that supports the ends of the floor joists or if there is settlement in the footings or foundations upon which the posts supporting the girder rest.
The amount of sag in joists can be determined by stretching a chalk line or string taut across the floor at right angles to the joists and tacking it to the surface of the floor on opposite sides of the room. If there is access to the space beneath the floor, such as a basement or excavated area, this sag can be corrected by the use of adjustable steel posts which operate as a screw jack to raise the sag in the joists until the surface of the finished floor is in line with the taut string. These jack posts may be«obtained from mail-order houses or hardware dealers at reasonable cost. Depending upon the size of the room, one or more may be necessary. The bottom of each post should rest on a firm bearing such as the concrete floor in a
basement or a concrete or masonry pedestal or base built on the ground in an excavated area. A^stout plank or beam of sufficient strength to carry the load and support the sagging joists should be placed on top of each post at right angles to the joists. The steel post may be left in place permanently or may be used as a tool in installing a wood post. If a steel post is left in place, it should be located under the center of the sag. On the other hand, if a wood post is preferred as a permanent installation, the steel post or jack should be placed far enough off center to allow space for the wood post to be inserted. After the wood post has been installed and made secure with hardwood shims or wedges between the top of the post and the bottom of the beam, the steel post can be removed.
To Level Sagging Floors
The amount of sag in the floor, caused by shrinkage in wood girders or the settlement of the posts that support them, can be determined with a string, carpenter's level, and rule by tacking one end of the string to the surface of the floor at an outside wall in a first-floor room and stretching it taut and level to a point above the girder where the settlement appears to be greater. At this point, the distance from string to floor can be measured to indicate the exact amount of settlement. To eliminate the sag, the girder can be raised with the steel jack post placed underneath and close to the supporting post by jacking up the girder until the floor is level. This steel post may be left in place permanently or merely used as a tool to raise the girder and insert shims. These shims or wedges may be either hardwood or metal placed between the top of the original post and the bottom of the girder. The steel post can then be removed.
Cracks in new floors are usually the result of shrinkage in floor boards which have not been properly seasoned or which have been exposed to excessive moisture before or during construction. Although it will not entirely conceal them, the cracks may be sealed with a filler which will set up hard and be durable.
Floors may creak when walked on for several reasons: if floor boards have not been properly laid, if they have not been properly nailed, if the floor boards or floor joists have become warped, or if the floor construction as a whole is faulty. Other causes for creaking floors are shrinkage and warping that results from the finish floor or the subfloor being damp when laid, warping that results from the finish floor being laid in the same direction as the subfloor, and warping that results from the finish floor being nailed directly to the joists, omitting the subfloor.
If the basement has no ceiling, the location and direction of joists under the first floor and whether the floor is single or double may be readily determined. In the case of the second-story floor, however, it is more difficult to be sure whether a floor is single or double. If the finished flooring on the second floor runs in the same direction as that on the first floor, it may be assumed that the same type of construction has been used for both floors.
The following tools and materials are needed: hammer, nail set, and block of wood; small quantities of fourpenny floor screw nails for 3/8-inch dressed and matched hardwood flooring, eightpenny floor screw nails for 1-inch common flooring, and tenpenny floor screw nails for 1-1/16-inch flooring.
The bridging of floor joists should be examined where exposed and strengthened or nailed securely at the points where creaking is evident. Floor boards that have become slightly raised from the joists may be forced back into position by laying a thick covering of old carpet or several thicknesses of paper over the raised portion of the floor to protect the finish, placing a block of wood on top of the covering, and striking the block with a heavy hammer to drive the flooring back into place. If this does not produce the desired results, a few nails may be driven around the loose area to draw the boards down tight. Resin-coated finishing or casing nails long enough to penetrate the subflooring and supporting joists should be used. Care should be taken not to bend the nails and, when the heads are within a quarter of an inch of the floor, a nail set should be used to drive the heads below the surface to prevent marring the floor with the hammer. The nail holes should then be filled with putty or wood filler and finished like the floor. If the top surface of the joists will not hold nails securely, it may be necessary to fasten blocking to the sides of the joists and drive the floor nails into the blocking.
If the methods described are not successful on the first floor, it may be supported and the creaking eliminated by driving a thin strip of wood between the bottom of the flooring and the top of the joists. Another method to stop creaking is to nail a cleat of wood to the side of the joists high enough to support the flooring. In extreme cases, it may be necessary to remove some of the finish flooring, nail the subflooring securely to the joists, and replace the finish flooring.
Cracks in Floors
Old floors often develop cracks which should be filled in. Clean out the space thoroughly so that your filler will adhere to the wood. Plastic wood fillers or putty are available for this particular purpose. Pack tightly because they tend to shrink as they dry out. You may make your own filler by mixing sawdust and glue.
If the opening is very large, it may be necessary to cut a strip of wood the required length and force it into the space, gluing into place.
Planing Worn Boards
Old floors may have worn down in much traveled areas and need to be evened. Have the floor perfectly clean and dry, giving attention to cracks which should be cleaned vigorously with a wire brush. Drive all nails below the surface so that they will not damage the sharp edge of your plane. Note carefully the high places of the floor and set a smoothing plane to make a medium cut. Be sure to work in the direction of the grain of the wood. Go over the high places in the floor.
Then set your plane to make a finer cut and work out irregular spots. Sandpapering is the last step.
Replacing Worn Boards
This is considerably more of a problem and many people find it worth while to employ the services of a carpenter if the floor is in bad condition. Examine the boards carefully and note where they have been joined. Where two boards meet, you will find the line of nails marks the position of a joist.
Bore a hole in the floor board near the side of the joist to permit a keyhole saw to be inserted. Saw the board as close as possible to the joist. Then work back along the board until you find its other end where it is nailed to another joist. You may either remove the entire board or, if only a portion is damaged, saw across near a joist and leave the other part. Pry up the rest of the damaged board from the joist and remove the nails with a claw hammer.
Be alert not to damage electric connections, water or gas pipes, whose location you can usually determine from the fixtures.
If the damaged area is of considerable size, so that several floor boards must be inserted, cut the replacement boards to uneven lengths so that they will not all be joined over the same joist, for this would obviously weaken the floor. It is well to nail a cleat to the side of the joist where the floor boards are to be joined, to give additional support. Such a cleat should be about 3 inches wide and 2 inches or less thick.
Where the flooring is made of tongued-and-grooved boards, the tongue has to be cut before you attempt to pry up the board. In extreme cases, the board may have shrunk so badly that this cutting is not necessary, but do not count upon it. However, it is best to be prepared to saw the board to be removed. Saw along the tongue before making cross cuts at the joints. Make an insertion with brace and bit and start with the keyhole saw, changing to compass saw or handsaw when space permits. This means that you will make three cuts in all. Then work the tongue from the board that remains and lift out carefully with a chisel.
When a stair board becomes loose, the difficulty may be in the stair tread or the riser that supports the tread. If the stair is of simple construction, either the worn tread or the riser may be removed and a new one cut to the exact size, using the broken or worn piece as pattern. Place the tread on top of the stringers (the side pieces) which support the stairway and nail the tread into the stringers with finishing nails. Nail the top of the tread to the riser below.
If the stairway is made of tongue-and-groove construction of treads and risers, the problem of replacement is considerably more difficult and greater skill must be exercised.
For finishing or painting the wood on stairs, follow the instructions which are given in this chapter for floor surfaces.
More by this Author
There are two main rules to remember when using a router. The first is that the machine has a low torque (turning power) so if you attempt to give it too much work load, for example by trying to make it cut too deeply,...