While some hardwood flooring can be purchased prefinished, the majority must be sanded and finished once the installation is completed In this chapter, you will learn how to finish your new hardwood floor using the methods and equipment that have been developed by professional hardwood flooring installers over many years. A following section will cover the refinishing of old hardwood floors.
Finishing your hardwood floor requires some specialized and expensive power tools. All can be rented, however, at most rental yards or from larger flooring-supply houses. Some suppliers will even loan you equipment free or at a nominal charge if you purchase the majority of your flooring needs through them. These primary pieces of floor-finish equipment include the drum sander, the power edger, and the floor polisher. Finish application equipment can also be rented or borrowed.
PREPARING THE FLOOR
Apply the finish to the hardwood floor should be one of the last jobs of construction project. In this way, other work and the traffic from workers won’t mar the finish. Wall coverings should be in place and the paint completed except for a final cost on the base molding. Sweep the floor clean immediately before sanding (FIG. 4-1).
Fig. 4-2: Drum-type floor sander
Fig. 4-3: Another type of drum sander has the paper held in place by a clamp
A drum-type floor sander (FIG. 4-2) is used for heavy sanding operations. A floor polisher with a sanding or screen disc or steel wool is used for special situations and to give the floor an extremely fine finish. Professional floor finishers will also use a spinner-type edger in areas where the drum sander can’t reach. Since the spinner-type edger is difficult to use, how ever, you may elect to hand-scrape and hand-sand around the edges of the room.
Load the drum sander with a medium abrasive (FIG. 4-3). Place the machine along the right-hand wall with about 2/3 of the length of the floor in front of you. Start the motor and ease the drum to the floor. Walk slowly forward, letting the machine pull you along at an even pace. As you near the wall, gradually raise the drum off the floor by lifting up on the control handle.
Start pulling the machine backward and ease the drum to the floor. Cover the same path as you made on the forward cut. When you reach your starting point, ease the drum from the floor and move the machine to one side by approximately 4 inches. Then repeat the forward and back ward passes. When 2/3 of the room has been sanded, turn the machine in the opposite direction and sand the remaining third in the same manner. Be sure the cuts made on the last 1/3 of the room overlap the first cuts by 2 to 3 feet. This method blends the two areas together.
It is very important that you never let the sanding drum touch the floor unless you are moving the machine forward or backward (FIG. 4-4). If you do, it will cut a hollow in the floor that cannot be removed.
After you finish the first cut with the drum sander (FIG. 4-5), use the power edger (FIG. 4-6) or a hand-scraper and sand up to the baseboard, in corners, closets, and other areas where the drum sander won’t reach. Use the same grit as used on the drum sander. Move the edger in a brisk, left- to-right semicircular pattern.
When using a hand scraper (FIG. 4-7) instead of the power edger, apply even pressure and scrape in the direction of the grain or from the wall into the sanded area if the floor is parquet. Avoid gouging the wood with the scraper. After scraping, use a sanding block and paper with the same grit as that used on the drum sander to smooth the flooring. A brick with a piece of old blanket glued around it makes a good sanding block.
After you have sanded the entire floor with a medium abrasive, repeat the entire procedure with a fine abrasive (TABLE 4-1) Sand the body of the floor first and then the edges Pay particular attention to blending the edges with the main floor area.
Often only two sanding cuts are used, but for a smoother, finer finish, switch from the drum sander to a floor polisher that has been fitted with fine paper or a screen disc and sand the entire floor. If the floor is to be stained, however, use a slightly heavier grit on this cut to leave a tooth on the wood surface, which will enable the stain to penetrate more readily.
Fig. 4-4: Always keep the drum sander moving when it is operating.
Fig. 4-5: Finishing the first cut w the drum sander.
Fig. 4.6: Use the power edger to sand up to the baseboard and in other areas the drum sander won’t reach.
Fig. 4.7 A hand scraper may be used instead of the edger to remove old finish in tight spots. The hand scrapper is recommended for the inexperienced.
Fig. 4-8: Sand in the longest direction of the room.
Fig. 4-9: Parquet, block, herringbone, and similar flooring should have three sanding cuts, as shown.
Table 4-1: Sanding New Floors
Sanding strip and plank flooring
If the floor is flat and level, make all the cuts parallel to the direction of the strips (FIG. 4-8). If the floor is uneven, however, make the first cut at a 45-degree angle to the direction of the strips. This will remove any peaks or valleys that are caused by minute variations in the thickness of the strips or in the subfloor. Make succeeding cuts parallel to the direction of the strips. Always use at least two cuts. A third and even a fourth cut with the floor polishing machine and sanding disc is recommended because of the fine finish it imparts to the floor.
Sanding parquet, block, and similar flooring
Use the drum sander for the first two cuts. Make the first cut with a medium-grit paper on a diagonal of the room and the second cut with a fine-grit paper on the opposite diagonal. Then switch to the floor polishing machine and, using a screen disc, make a third lengthwise cut following the longest room dimension (FIG. 4-9).
PREPARING FOR THE FINISH
When the sanding is completed, sweep or vacuum the floor clean (FIG. 4-10). Wipe up all the dust on windows, sills, doors, door frames, base- boards, and the floor using a painter’s tack rag.
Inspect the floor carefully and hand-sand to remove any scratches or swirl marks. Fill the cracks, spaces, and nail holes with a commercial putty of a matching color, which is compatible with stain and/or finish, or make your own putty with fine dust from the final sanding and a floor sealer. Mix them to form a thick paste. Apply the putty with a putty knife and scrape off the excess. When it has dried, hand-sand it with a fine-grit paper. When these operations are finished, both old and new floors become essentially new wood surfaces and should be treated as new floors.
Fig. 4-10: The sanded hardwood floor.
Apply the first coat of stain or other finish the same day that the sanding is completed to help keep the wood grain from rising and creating a rough surface. With stain and all finishing materials, be sure to read and follow the label instructions. Avoid vigorous shaking or stirring, which may cause air bubbles to be trapped in the material and affect the quality of the finish. Allow adequate ventilation and avoid breathing of the fumes for prolonged periods.
Finishing your hardwood floor involves numerous products, such as a sealer, stains, shellac, and varnish (FIG. 4-11) and application equipment (FIGS. 4-12 through 4-15). To guide you, TABLE 4-2 suggests numerous types of finishes for the specific types of wood that are used in home construction.
Fig. 4-11: Popular hardwood flooring finishes include varnish, sealer, and shellac
Fig. 4-12: Hardwood flooring finishes are often applied using a brush
Fig. 4-13: Typical varnish brush.
Fig. 4-14: Two large flat brushes.
TYPES OF FINISHES
Let’s consider the properties and the methods of application for the more popular finishes that are used on hardwood floors: penetrating scalers, surface finishes, polyurethane, varnish, shellac, lacquer, and bleaching.
Fig. 4-15: Right and wrong way to clean brushes in solvent.
Table 4-2: Home Interior Woods
Fig. 4-16: Older hardwood floors may require wood filler to fill between boards that have dried with age.
Fig. 4-17: Use a small brush to apply finish around the edges of the floor.
Fig. 4-18: A long-handled lamb’s wool applicator is excellent for applying penetrating sealer finishes.
Fig. 4-19: Apply the finish in the same direction as the wood’s grain.
Fig. 4-20: Work your way through the room and into the next room, making sure you have an exit when you are done.
This is the finish that is recommended for most residential floors. The sealer soaks into the wood pores and hardens to seal the floor against dirt and most stains. It wears only as the wood wears and will not chip or scratch. After years of wear, the floor can usually be refinished without sanding by cleaning it and applying another coat of sealer or a special reconditioning product. Limited areas of wear can be refinished without showing lap marks where new finish is applied over the old.
Penetrating sealers can also be used as an undercoat for varnish or shellac when a high gloss is desired. They are available in natural, a number of wood tones, and other colors.
There are two basic types of sealers, which are distinguished by their drying time requirements. Normal or slow-drying sealers can be used safely by anyone. Fast-drying sealers should be used only by a professional who is accustomed to handling and applying them and can complete the job within the allotted drying time to avoid lap marks or a splotchy appearance. Some sealers produce satisfactory results with one coat, but most manufacturers recommend two coats or one plus a special top dressing.
Make sure that the space between boards has been filled before applying a sealer (FIG. 4-16). Then brush sealer around door edges (FIG. 4-17). Sealers are mopped on the general floor area. Use a clean string mop or long-handled applicator with a lamb’s wool pad (FIG. 4-18). Secondary choices for applicators are a wide brush or squeegee. Generously apply the sealer and wipe up the excess with clean cloths or a squeegee.
Note: Some manufacturers call for the sealer to be rubbed into the wood with steel wool pads on an electric buffer while the sealer is still wet. Figures 4-19 through 4-22 illustrate the application of penetrating sealer.
Allow the sealer to dry and then buff the floor with No. 2 steel wool by hand or use an electric polisher that is equipped with a steel wool pad (FIG. 4-23). For even greater gloss and maximum protection from wear, use a single application of a penetrating sealer and then buff with steel wool. Follow this with two coats of polyurethane, the application of which will be covered later.
Fig. 4-21: The finished floor will have a bright sheen as it shows off the wood’s natural grain and character.
Fig. 4-22: The finished hardwood floor.
Fig. 4.23: Ordinary steel wool pads may be used with the floor polisher when buffing a sealer finish.
Fig. 4-24 Work in the direction of the boards.
If other than a natural finish is desired, coloring must be the first step in the finishing process. Let’s first look at coloring sealers and stains.
Colored penetrating sealers: These are generally available in a number of wood tones and several other colors. They are an easy finishing method since the floor is colored as part of the operation. Their application will be covered later
Pigmented wiping stains: These are penetrating, oil-resin products to which pigments have been added. The pigments are not in solution, but in suspension, so the material must be stirred regularly during use to maintain a uniform color. The pigment collects in the open pores of the wood and accentuates the grain pattern.
Varnish stains: These are a formulation of varnish with an oil-soluble dye that provides the color. As with penetrating sealers, you color the wood at the same time you apply the finish coat. The main disadvantage to varnish stains is that they tend to obscure the wood grain to a great extent and thus do not provide nearly as beautiful a finish as one of the other methods.
Stains are applied by brushing on a generous coat. The pigment is allowed to penetrate the wood and then it is wiped off with clean rags. Wipe vigorously to remove as much stain as possible from the surface.
The pigment that remains in the pores and grain lines will provide the colot Always test the stain on an extra board because the length of time the stain is allowed to remain on the floor will determine the degree of color tone provided.
All of these finishes are applied with a high-quality brush or lamb’s wool applicator that is designated for use with the particular type of finish selected.
On strip and plank flooring, work in the direction of the boards in a path narrow enough to keep a wet working edge as you move across the room (FIG. 4-24). With block and other patterned floors, apply the finish in strips the width of one block, or about 12 inches for other types. Work from wall to wall across the shorter room dimensions.
Lap strokes by working from the wettest area back into the area that was just covered. Follow the manufacturer’s directions for drying times between coats.
Finish manufacturers have done much to improve polyurethanes in the past few years. These blends of synthetic resins, plasticizers, and other film-forming agents produce an extremely durable surface that is moisture-resistant. They are the best choice for kitchens, commercial applications, and other areas that are exposed to stains, spills, and high traffic.
There are two types: oil-modified and moisture-cured. The first type of polyurethanes are air-drying materials—the solvents pass off in vapors.
Because of the toxic fumes, oil-modified polyurethanes should not be applied by the nonprofessional.
Moisture-cured polyurethanes absorb small quantities of moisture from the air, which causes them to cure and harden. While slightly more wear-resistant than the air-drying type, the moisture-cured polyurethanes are extremely difficult to apply properly Both the relative humidity or amount of moisture in the air, and drying time are crucial. Moisture-cured polyurethanes are thinner than oil-modified ones so that they typically take more coats to complete. On the plus side, they usually don’t discolor with age so they can be touched up without concern for matching tones.
Somewhat similar to polyurethanes are the epoxy and urea-formaldehyde finishes, which are also synthetic products with high durability. The type of undercoat, working time, number of coats, and other factors are all critical and make application difficult, They should only be applied by the highly skilled.
Caution The adhesion of polyurethanes, epoxies, and urea-formaldehyde finishes is affected by wax and grease, as well as some types of stains, bleaches, or sealers. Further more, one type of polyurethane may not be compatible with another type. Always make a test in a closet or some other inconspicuous place to be sure that the finish will adhere and dry properly. This is particularly important when you are refinishing an old floor, since some of the old finish may have penetrated the wood fibers below the level to which it has been sanded.
Use a brush or lamb’s wool applicator to apply the polyurethanes and work along the grain to get a smooth, even coat. Allow the drying time as specified by the manufacturer, then buff with steel wool. Dust thoroughly and apply a second coat along the grain of wood. The final coat does not require buffing.
For a particularly good finish that combines the best qualities of a sealer and a surface coating, use a penetrating sealer followed by one or more coats of polyurethane. Check the product labels to be sure that the sealer and top coat are compatible.
Use only varnish manufactured for flooring applications, since it is more durable than ordinary varnish. Varnish gives a glossy finish that has good durability and is resistant to stains and spots. It shows scratches, however, and worn spots are difficult to patch without showing lines between the old and new finishes.
Varnish drying time is 8 hours or more. Use three coats over bare wood, or two coats over a wood filler or a shellac or sealer undercoat.
Thin a clear varnish with one part thinner to eight parts of varnish for the first coat over bare wood. Use full-strength varnish over penetrating a stain, shellac, or colored varnish. Apply all succeeding coats full strength and observe the drying times recommended by the manufacturer. Remember that varnish takes much longer to dry than shellac or lacquer.
Flow varnish on as smoothly as possible and brush out each stroke. Sand with a fine grit sandpaper between coats. Dust well and wipe with a turpentine-dampened rag between coats. Use two or three coats.
Shellac is easy to apply and dries fast. Two or three coats can be applied in one day It is moderately resistant to water and other staining agents, but will spot if liquids are not wiped up promptly It gives a high gloss and will not darken with age as quickly as varnish. Use at least two coats and preferably three. Shellac may be used as a sealer under a varnish top coat.
The main disadvantage to shellac is that it chips easily Repairs can be made by sanding the chipped or worn area and then touching it up with new shellac. Be careful to feather the new finish into the surrounding area.
Use a 3-pound cut -- 3 pounds of shellac dissolved in 1 gallon of denatured alcohol. Apply with a wide brush to get a full, smooth flow and avoid puddling. Allow it to dry 2 hours and then sand with fine paper. Dust and recoat. This time, allow 3 hours drying time before you apply a third coat. Sand with a fine grit paper, then dust before the third coat. Use extra-fine paper to smooth the final coat. Allow the shellac to harden overnight before you use the floor.
Lacquer provides a glossy finish with about the same durability as varnish. An advantage to lacquer is that worn spots may be retouched, since the new lacquer dissolves the old and blends with it rather than forming an additional layer. Lacquer is difficult to apply because it dries so quickly, which causes lap marks. The use of lacquer by individuals other than skilled applicators is not recommended. Two coats are required.
Apply lacquer with a wide brush or mohair roller. Work fast to pre vent lap marks. Allow the first coat to dry 1 hour, then hand-sand with a fine grit paper and dust. Apply the second coat and allow it to dry over night before you use the floor. Do not sand the final coat. For a three-coat job, allow an hour for the second coat to dry, then sand with a fine grit paper, dust, and apply a third coat that has been reduced with one part thinner to four parts lacquer. Be sure to use a thinner that is recommended by the lacquer manufacturer to avoid drying problems.
An interesting effect can be obtained on both new and old floors by bleaching the wood to remove the color without obscuring the grain pat tern. The general tone of the wood is retained, but the color intensity is reduced.
Wood bleaches are available at most paint stores. The best are usually two-solution products. The first solution is brushed on and changes the pigments chemically, while the second solution removes the pigments. Before using a bleach, be sure that the flooring is clean and free from oils, grease, old finish, and any dirt that might repel the bleach, prevent it from working, or give it an uneven effect.
Since bleaches have a water base, their use will cause the grain of the flooring to rise. Sand the floor with a fine grit paper after using the bleach to restore the floor to the required smooth surface.
Follow manufacturer’s instructions for application times on the bleach you use. It’s a good idea to make a test on a piece of scrap flooring because the length of time the bleach remains on the floor will affect the amount of color that is removed.
A polyurethane finish may be applied to the bleached floor. Some finishers prefer, however, to follow the bleaching operation with a white stain or a wood filler that has been mixed with wood pigment, which gives the whitest floor of all. Then they use polyurethane for the final finish. Check the product label to be sure it is compatible with the stain or pigmented filler you want to use and that the polyurethane will not turn an amber color over the whitened floor.
Most hardwoods have minute crevices that are exposed by sawing and sanding. Before the development of modern finishing products, it was common to use a wood filler to fill these crevices or pores. Penetrating sealers and polyurethane finishes do not require their use, and fillers are quite often omitted with other finishing materials as well.
There are, however, two situations when the use of a filler is helpful. One is when a mirror-smooth finish is desired, usually with varnish as the top coat. By filling the pores of the wood, you get an absolutely smooth surface that, with a gloss varnish, has an extremely high light reflectance.
The other use for fillers is when a floor is colored. In this case, a pigmented filler of the desired color tone is applied. This process is identical to bleaching, except that the filler is tinted instead of white.
Apply the filler with a 4-inch, short-bristled, flat brush. Cover a small area at a time. Brush with the grain first, then across the grain. When it dulls over, but before it hardens, wipe it vigorously with burlap or other coarse rags. Wipe across the grain first, then with the grain. Move on to another area until all the flooring is filled. Let the filler dry for 24 hours and then disc sand with a fine grit paper before you apply other finish materials.
Fig. 4-25: Many interesting effects may be obtained by stenciling
Decorative boarders or overall floor patterns can be applied to hardwood floors with the use of stencils and masking tape, which are available at many paint and decorating stores. The stencils or tape must be securely adhered to the finished floor surface to prevent the final color from bleed ing beyond the area that is to be treated. Refer to FIG. 4-2 5.
One method uses a clear or light-colored penetrating sealer over the entire floor area and a darker color sealer to create the pattern. For a more vivid color and pattern, use a good-quality floor enamel. Always make a test panel first to be sure you get the desired effect. If you use paint, it will adhere more satisfactorily to the base finish.
Use paint sparingly and in other than high-traffic areas because it will chip and scratch easily. It should always be protected with one of the surface finishes described earlier to help prevent such damage.
GYM AND ROLLER-RINK FLOORS
The sanding and other initial preparations for applying a finish to gym floors are identical to those for floors in other installations. Special finish ing products are made to provide the gloss and slip- and abrasion-resistant characteristics that are required, as well as to permit the painting of the game lines. Use only products that are manufactured for such applications and follow the specific finishing schedule that is provided since this varies from one product to another. Deviations from the recommended procedure may effect the quality and performance of the finish.
For those who are installing gymnasium or game floors of hardwood, we later will give the specific markings and measurements for most popular gym games.
PROTECTING THE FLOOR’S FINISH
For the final touch of beauty and to protect the finish, apply one or more coats of good wax. Use either a liquid buffing wax/cleaner or paste wax. Use only brands that are designated for hardwood floors and, if a liquid, be sure it has a solvent, not a water base.
Apply the wax after the finish coat is thoroughly dry and polish it with a machine buffer, The wax will give a lustrous sheen to the floor and form a protective film that will prevent dirt from penetrating the finish.
Caution: Some manufacturers of urethane finishes do not recommend waxing, especially for commercial jobs, because the wax may make the floor slippery Gymnasium and roller-rink floors should never be waxed. They require special maintenance products and procedures that are avail able from several manufacturers that also produce the finishing materials for such installations.
PROTECTING BASE MOLDINGS
Fig. 4-26: Base moldings serve as a finish between the hardwood flooring and the wall.
Fig 4-27: Cross section of molding applied over hardwood flooring.
Base moldings serve as a finish between the finished floor and wall (FIGS. 4-26 and 4-27). They are available in several widths and forms. The simplest is made by butt-jointing two pieces of wood at an inside corner (FIG. 4-28).
Fig. 4-28: Butt-joint baseboard.
Fig. 4-29 Baseboard topped with a small base cap ranch base (C). (A). a narrow ranch base (B) and wide.
A two-piece base consists of a baseboard that is topped with a small base cap (FIG. 4-29A). When the plaster is not straight and true or a hard wood floor needs an expansion gap, the small base molding will more closely conform to the variations than will the wider base alone. A common size for this type of baseboard is 5/8 x 3 1/4 inches or wider.
A one-piece base varies in size from 7/16 inches to ½ x 3 ¼ inches and wider (FIGS. 4-29B and 4-29C). Although a wood member is desirable at the junction of the wall and flooring to serve as a protective bumper, wood trim is sometimes eliminated entirely
Most baseboards are finished with a base shoe that is 1/2 x 3/4 inches in size. A single-base molding without the shoe is sometimes placed at the wall-floor junction.
Square-edged baseboard should be installed with a butt joint at the inside corners and a mitered joint at the outside corners (FIG. 4-30). It should be nailed to each stud with two 8d finishing nails. Molded single-piece bases, base moldings, and base shoes should have a coped joint at the inside corners and a mitered joint at the outside corners.
Fig. 4-30: Miter joints at outside corner molding.
A coped joint is one in which the first piece is square-cut against the plaster or base and the second piece is coped. It is accomplished by sawing a 45-degree miter cut and then trimming the molding along the inner line of the miter with the coping saw (FIG. 4-31).
Fig. 4-31: Coping an inside corner molding.
The base shoe should be nailed into the subfloor with long, slender nails and not into the baseboard itself or the hardwood flooring. Thus, if there is a small amount of movement in the hardwood flooring, the molding will allow this movement while covering it.
To guide you in the selection and installation of common molding types, let’s look at some of the more popular designs (FIG. 4-32).
The term contour cutting refers to the cutting or ornamental face curves on stock that is to be used for molding or other trim. Most contour cutting is done on the shaper, which is equipped with a cutter or blades, or with a combination of cutters and/or blades that are arranged to pro duce the desired contour.
The simple molding shapes, which are shown in FIG. 4-32 are the quarter round, the half round, the scotia or cove, the cyma recta, and the cyma reversa. The quarter and half round form convex curves. The cove molding forms a concave curve. And the cyma moldings are combinations of convex and concave curves.
Fig. 4-32: Common molding shapes: Quarter round; Half round; Scotia or cove; Cyma-recta; Base shoe; Cyma-reversa
Fig. 4-33: Shaping abutting members.
Inside corner joints between the molding trim members are usually made by butting the end of one member to fit the face of the other member.
First, saw the end of the abutting member square, as you would for any ordinary butt joint between ordinary flat-faced members. Then miter the end to 45 degrees, as shown in the first and second views of FIG. 4-33. Set the coping saw at the top of the line of the miter cut, hold the saw at 90 degrees to the lengthwise axis of the piece, and saw off the segment shown in the third view. Closely follow the face line left by the 45-degree miter cut. The end of the abutting member will then match the face of the member, as shown in the third view. This is called a coping joint.
You’ve now completed the finishing of your hardwood floor. The floor has been prepared, sanded, and a finish installed. The molding around the edge has been cut and installed. All that’s left is to enjoy your beautiful hardwood floor.
To ensure that your floor will give both beauty and function for many years, you’ll want to maintain it properly.
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