Water marks, nicotine, smoke and some organic stains can migrate through ordinary wall paint.
First remove the source of the stain and allow the surface to dry fully.
A suitable stain-blocking primer may then be required before applying the finish coats.
Identify the stain
Water marks, nicotine, grease and wood extractives can reappear through ordinary paint. Repair an active leak first. Degrease with an appropriate cleaner; superficial wiping may not be enough. Select a blocking primer suited to the stain type.
Make a small trial
Apply the preparation, primer and finish to a test area and assess it after drying. Follow the manufacturer's compatibility and coat instructions. Adding more ordinary paint may increase consumption without blocking the stain. Treat an old dry mark differently from a new damp stain.
Before correcting the defect
- Assess the defect on a fully dried surface.
- Identify causes of moisture and poor adhesion.
- Trial the selected repair system on a small area.
Should blocking primer cover the whole wall?
Decide according to the product and stain extent. Local priming can create absorption or sheen differences in the finish. Inspect the trial result and follow the recommendation for the complete system.