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How to prevent paint lap


A beautifully painted living room with unfortunate and avoidable paint lap marks.
Lap marks in paint appear as a deeper color or an increased gloss where wet and dry layers overlap during paint application. Keeping a “wet edge” is the key to avoiding lapping paint. While painting, you need to move quickly enough so, the paint being applied can seamlessly flow into the just-applied paint.

What Causes Lap Marks?

Lap marks while painting can occur for a variety of reasons, including:
  • Painting in direct sunlight or too much wind causing the product to dry too quickly
  • Applying a different thickness than what is recommended on the Technical Data Sheet (See TDS)
  • Using poor-quality paints
  • Coating a porous surface that makes the paint dry too quickly

How to Prevent Paint Lap Marks

Use the following methods to prevent lap marks:
  • Brush and roll from "wet to dry" rather than vice versa, to produce a smooth, uniform appearance
  • Apply a primer or sealer to seal the surface and create uniform porosity when the substrate is very porous (follow label and Technical Data Sheet priming recommendations for bare substrates)
  • Use enough paint, a consistent application technique and the right pace to ensure even application
  • Paint in manageable area sizes to maintain a “wet edge”

How to Keep a “Wet Edge”

Keeping a wet edge by applying paint a short distance away from the portion you just painted and rolling or brushing back into that wet area prevents lap marks.
  • Plan breaks at natural interruptions such as a window, door, or corner
  • Cut into planned breaks with a brush while wall paint is still wet
  • Use quality paints and apply them per the directions to help avoid lapping