Finishes for wood floors

Wood flooring that has been excessively worn, overloaded, abused or subject to water damage will have to be restored (sanded) and refinished. Wood flooring is available both prefinished, including acrylic impregnated, and site-finished.

Recommendations for refinishing prefinished as well as site-finished flooring can be obtained from the manufacturer. Each floor finish has its advantages and disadvantages. Some of these are subjective, and there is no consensus on the best finish, especially since job conditions vary considerably.

However, general attributes for the most popular finishes follow.

WATER-BASED URETHANES

Water-based urethanes are usually combinations of urethanes and acrylics with a catalyst mixed prior to application. In general, the higher the percentage of urethane, the more durable and expensive.

• ADVANTAGES: Contain fewer volatile organic compounds (VOCs) and are less noxious than other finishes. Clearer, less yellowing than other finishes. Good durability, fast drying, non-flammable. Becoming increasingly popular.
• DISADVANTAGES: Somewhat less durable than other urethane finishes. Require more coats than solvent-based urethanes to achieve comparable film thickness (up to four coats). New coats may not adhere well to old coats.

OIL-MODIFIED URETHANES

Oil-modified urethanes are technically oil-based; examples include linseed and tung oil.

• ADVANTAGES: Until recently the most popular urethane finish and still favored by many users. Requires fewer coats than water-based methanes. Very durable and commonly available. Easy to recoat.
• DISADVANTAGES: Imparts a yellower cast than other urethanes. Slow to cure and may require sanding between coats. High VOC contents, requires proper lung, eye, and skin protection. Combustible.

MOISTURE-CURED URETHANES.

Moisture-cured urethanes react with the humidity in the air to dry.

• ADVANTAGES: Excellent durability. Provides the hardest wearing surface. Dries rapidly in moist environ-ments. Recoatable.
• DISADVANTAGES: Difficult to apply - should be left to professional finishers. Available only in glossy finishes. High levels of VOCs; requires careful lung, eye, and skin protection. Extremely flammable. Significant changes in humidity can lead to blistering or other defects.

SWEDISH FINISHES

A type of finish, typically acid-cured (containing formaldehyde) and sometimes water-based, that produces high performing but expensive finishes.

• ADVANTAGES: Excellent durability, transparency, and elasticity. A popular product among professionals. Recoatable, fast drying.
• DISADVANTAGES: High VOC content and presence of formaldehyde in acid-cured formulas restricts application to professionals. Difficult to apply and requires carefully sanded floor. Combustible.

OIL FINISHES

Most penetrating oil sealers/finishers are combinations of highly modified natural oil, such as linseed or tung oil, with additives to improve hardness and drying. Adding wax to oil-finished floor will afford protection against spills and abrasion, although the manufacturers of some finishes such as Velvit oil maintain that their products do not require wax.

• ADVANTAGES: Easy to apply and repair (just brush or rub on another coat). Good durability. Will not crack, craze or peel. Low luster - popular with installers and users of traditional softwood flooring.
• DISADVANTAGES: Not as durable as other finishes. Can take a long time to completely cure. Surface may collect dust. Can water-spot. Some finishes require waxing. Strong initial odor. Combustible.

WAXES

With the increased use of urethane finishes, waxes (typically paste waxes) are not as common as they once were. Most manufacturers of urethane finishes do not recommend the use of waxes over urethanes because of added maintenance. Waxed surfaces require a stain or grain sealer prior to waxing.

• ADVANTAGES: Protects and extends life of oil finishes. Easy to apply and surprisingly durable. Fast drying.
• DISADVANTAGES: Requires maintenance (touch-up, buffing, and periodic removal with wax removers or sanding, and rewaxing). Becomes brittle and can yellow flooring. Can be slippery when wet -- not suggested in kitchens, entryways, or bath/powder rooms. Contains VOCs; strong initial odor; can water-spot.