In many cases, new paint can be applied over an existing coating if it is sound, clean and firmly bonded.
If the old coating is peeling, blistering or affected by moisture, simply painting over it will not solve the problem.
Clean the surface, remove unstable areas, repair defects and use primer where needed.
When recoating is possible
The old coating's adhesion and cleanliness matter more than its age alone. It must be sound, dry and compatible with the new system. Remove blistered or peeling material and clean grease and dirt. Glossy surfaces may need further preparation and a suitable adhesion primer.
Check compatibility
Try the complete preparation and coating system on a small area. Assess appearance and adhesion after the recommended drying period. Applying water-based paint over an older oil-based coating requires the preparation specified for that system. Excessive thinning and expecting primer to cure every substrate defect are common mistakes.
Before coating
- Confirm the surface is dry, sound and free of dust.
- Match repair materials and primer to the substrate.
- Check waiting times for each layer in its own instructions.
Can I paint over a small blister?
Loose or blistered paint is not a dependable base. Remove it and investigate the cause. If moisture is present underneath, resolve its source before repairing and painting.