SEALER SERIES Part 9: Sealer Application Tips

Each type of sealer has a recommended applicator and coverage rate, as discussed in Part 8: Choosing the Best Applicator. But simply using the right application tool won’t guarantee good results. You also need to practice the proper application techniques to avoid bubbles, blisters, lap lines and other eyesores.

The most common application problem is applying too much sealer at once (remember the phrase “thin to win”). Sealers are designed to perform best at a specific thickness, depending on the type of resin. This is determined by the coverage rate for that particular sealer. A good analogy is to compare sealers to a deck or cards. The first and second cards dealt are close to the surface, hard to pick up and very stable. The more cards you put on the pile, the more unstable the pile gets. The same holds true for sealers. The first and second thin coats are very stable, have good adhesion and provide good durability. The more you apply, either in one or multiple applications, the more unstable the system gets. With solvent-based systems, the signs of overapplication are typically bubbles, blisters and white haze. With water-based systems, you’ll often see blisters, foam and a milky white cloudiness.

Another common application mistake is lap lines, or uneven application. When applying sealer, always go back over the previous pass about 2 inches as you move across the surface. This overlap needs to occur when the sealer is still wet, so the two passes blend and become one. If the first pass dries, the second creates a lap line and can be seen after the entire floor is dry. Fixing the problem usually requires applying another full coat of sealer.

When applying sealer by sprayer (whether using an LPHV, airless or pump-up type) make sure to maintain constant pressure and use the proper tip. A cone-shaped spray pattern is better than a fan pattern, and the more atomized the sealer the better.

When applying sealer by roller, make sure to buy a roller suitable for the sealer type (water- or solvent-based) and a nap thickness appropriate for the surface. When rolling on water-based sealers, be careful not to over-roll, which can causing foaming and blisters. You also may need to dip the roller more often. Some newer acetone-based fast-drying sealers can’t be roll applied because they flash off too fast.

When using a lamb’s wool applicator, micro-fiber applicator, synthetic mop or T-Bar, the application process is the same. Pour the sealer on the surface, and push and pull the product while maintaining a wet edge until you achieve the desired thickness. These application methods are very good for water-based sealers because they don’t foam and you can see the white sealer go clear as you push and pull it around the floor. However, they will only work on smooth floors.