Roller Marks – What Causes Them and How to Avoid Them

Roller marks in a water-based sealer can be avoided by using the right
application tools and techniques.

Question:
We applied a water-based acrylic sealer to a chemically stained floor in the front lobby of a commercial building. Within 24 hours after sealer application, a very distinct roller pattern could be seen on the floor (see photo). What caused the roller marks, and how can we avoid them in the future? Can we fix this problem now that the building is open for business?

Answer:
Roller marks are very frustrating, because they occur near the end of the project and tend to be the first thing people see when they look at the floor. Two different factors can cause roller marks. The first is not maintaining a wet edge when applying the sealer. This happens when one pass of sealer dries to a point where an adjacent pass can’t combine or blend with the previously applied layer and instead sits atop the surface creating an edge, or roller mark. The second factor is the type of roller or applicator used. A roller, by nature, tends to put down more material at the ends than in the middle.

You can minimize or eliminate roller marks by using the right roller nap thickness or by switching to a different type of applicator altogether. When applying a one-part water-based acrylic sealer, as in this case, it’s best to use a microfiber pad, since water-based sealers and finishes in general go on better when applied in a circular motion versus rolled in long, straight patterns. Another alternative is to use a roller, but apply the sealer in shorter V or W patterns to minimize lap marks.

The best remedy for removing roller marks depends on their severity. For minor roller marks, you may be able to remove them by high-speed buffing or simply hide them by applying multiple coats of finish wax. In this case, however, the marks are very noticeable and cover the entire floor, so stripping of the sealer is the recommended course of action. Because the building is occupied during the day, this process should take place at night. It may be necessary to strip the floor in sections if very large areas are affected.