Sagging
What it means
Excessive downward flow of a wet coating can create runs or sags, especially on vertical surfaces. Possible contributors include film thickness, viscosity, substrate/application conditions and drying behaviour.
What to check
- Surface preparation and cleanliness
- Compatibility of previous and new coating
- Application method and film build
- Drying/curing conditions
- Manufacturer instructions and technical data
For a product-specific diagnosis, identify the exact product and surface and consult the current manufacturer guidance.