Identify the surface and follow the current instructions for your exact products. Do not sand or strip uncertain old coatings. Read the safety guide before disturbing materials.
What the finish might be telling you
Several different causes can look similar. Use this as a starting point for investigation, not a remote diagnosis.
| Symptom | Possible causes | Next check |
|---|---|---|
| Peeling or flaking | Poor adhesion, contamination, loose layers or moisture | Find which layer is failing and whether the background is dry and sound. |
| Patchy sheen or flashing | Uneven absorption, local repairs or inconsistent application | Check priming, spread rate, drying and whether patches were sealed. |
| Bubbles or blisters | Moisture, heat, trapped air or incompatibility | Look at conditions and retained layers before applying more paint. |
| Cracks or crazing | Movement, unsuitable layers or coating before a repair is ready | Check the substrate, caulk cure and compatibility. |
| Runs and heavy texture | Too much paint, unsuitable tools or working after paint starts to set | Let the coating dry sufficiently before an approved repair. |
Go back to the weakest layer
Paint is only as secure as the material beneath it. If a new coat pulls an old layer away, the bond to the wall was already a weakness. A stronger primer over loose paint will not make that loose layer reliable.
Check the substrate, cleaning, primer, dilution, coat thickness and timings. A mistake in any one stage can show up much later. Be honest about conditions; a cold room can change the whole drying schedule.
Repair the cause, then the appearance
For safe modern coatings, remove unsound material using an appropriate method, make suitable repairs and rebuild the specified system on a sound foundation. Trial a small area before repeating a failed approach across the room.
A local touch up may show even with the original paint because of ageing, sheen or roller texture. Once the cause is resolved, a full coat to a natural boundary may give a more even result.
Common mistakes
- Adding another coat before identifying why the last one failed.
- Sanding a coating that is still soft.
- Assuming a visible defect has only one possible cause.
Pause for suspected hazardous old paint, damp, structural movement or widespread coating failure. Investigation comes before removal.
Sources & further reading
Original general guidance from Aethos, informed by the resources below. These references cover relevant safety, materials or techniques, not a specification for your property. Product examples are not paid recommendations.
- Zinsser: Bulls Eye 1 2 3 technical information (opens in a new tab)
An example of why preparation, substrate suitability and recoat instructions are product specific.
- Farrow & Ball: paint finishes (opens in a new tab)
Different products and sheen levels for different surfaces. Check the current product advice sheet.
- HSE: lead in construction (opens in a new tab)
Why disturbing older lead paint requires a planned, controlled approach.