Using Rollers

What causes common finish problems?

Streaking is caused by the dragging and subsequent poor dispersion of

the silica (flattening agent) in the polyurethane finish. These areas of varying concentrations of silica can cause areas of high and low gloss. Stop marks are a result of the silica being deposited on the floor after lifting an applicator. Lap lines occur when the finish does not properly flow and blend into a smooth film. This can be a result of too much finish on the floor from a roller that is too thick, or the loss of wet edge from the finish drying too quickly. All of these problems are accentuated by dark floors and low windows.

What’s the answer?

An increasing number of contractors are successfully using rollers to apply PoloPlaz Oil Modified Polyurethanes. Rollers provide consistent film thickness that conventional lambswool applicators sometimes lack. Because the finish is applied consistently over the surface of the floor, thick and thin spots, laps, and brush marks are eliminated. The high level of shear induced by roller application will reduce the viscosity of the finish. This reduction in viscosity improves the leveling characteristics of the finish providing a smooth surface.

Choose the Proper Roller

Choose a good 1/4” nap mohair roller made for all paints (rinse with Mineral Spirits before use). A 1/4” nap roller will apply finish at approximately 500 sf/gal (3 mil wet film thickness). These rollers can be reused several times. Clean with mineral spirits and store in a sealed container to avoid drying out.

Use Proper Rolling Technique

Roll the finish in a back and forth motion in a “W” pattern. Start and stop marks can be eliminated by keeping a good “wet edge” and working a small area. Rollers will induce air into the finish but all air will dissipate quickly.

Cold and Wet Conditions

If the polyurethane is cold the viscosity will increase dramatically. This can impair flow and leveling. Avoid applying cold finish. Warm the finish for at least 24 hours before applying. 70 – 80°F is ideal.

Pay special attention to the temperature of the floor. Uninsulated floors can be much colder than expected. This will immediately cool the finish upon application and impair both drying and flow. Always insure that the temperature of the floor is above 55° F.

Hot and Dry Conditions

Moderately warm temperatures (75 – 80°F) will improve the flow and drying of most finishes. Excessive heat (above 85°F) will speed the evaporation of solvents during application and cause it to flow poorly. In these conditions, control the temperature and eliminate air flow during application.

Sunlight through windows can sometimes cause hot spots on the floor. When finishing over a hot spot, the solvents will flash off very quickly and not allow the finish to flow out properly. If a hot spot is noticed, cover the window and allow the floor to cool down to room temperature before applying finish.

Reprinted at Wood Flooring Guy with permission from Bill (National Sales Manager) at PoloPlaz ( Visit their site for more information.