Short answer
Before painting a facade, the most important question is not the colour but whether the surface is ready to receive a coating. Moisture, loose old paint, cracks and contamination can cause a new finish to fail again if they are not dealt with first.
1. Check for moisture sources
Water can enter around roofs, gutters, windows, pipe penetrations, facade joints and areas close to the ground. If old paint is peeling, check whether water is contributing to the failure.
Do not paint a damp surface. Rain, dew and condensation can leave a substrate wetter than it appears.
2. Check the adhesion of the old coating
Loose, blistered, cracked or flaking paint is not a sound base for a new coating. Remove weak material back to a firm surface and smooth the edges of repaired areas so the transition does not show through the finish.
3. Clean the surface
Dust, dirt, salts, algae, grease and other contamination can reduce adhesion. Use a cleaning method suitable for the facade material and allow the cleaned surface to dry fully before painting.
4. Inspect cracks and joints
Pay special attention around windows and doors, at transitions between different materials and along old sealant joints. Small gaps may be repaired with a compatible paintable sealant. Cracks that repeatedly reopen or appear structural should not simply be hidden with paint.
5. Decide whether primer is needed
Bare mineral surfaces, repaired areas, highly porous substrates and surfaces with adhesion concerns may need a suitable primer. Choose the system according to the substrate rather than automatically applying the same primer everywhere.
6. Check the weather
Follow the coating manufacturer’s limits for temperature, humidity and rain-free time. Many failures begin not during application but because drying conditions were unsuitable.
A facade heated by strong direct sun can also cause paint to dry too quickly.
7. Match the coating system to the facade
Concrete, plaster, masonry, wood and metal do not all require the same preparation or coating system. Identify the substrate and any existing coating before choosing the finish paint.
Common mistakes
- Repainting peeling areas before solving the moisture source.
- Leaving loose old coating in place.
- Painting a washed facade before it has fully dried.
- Trying to hide every crack with paint alone.
- Ignoring the product’s temperature and recoat instructions.
When should you call a professional?
Deep or recurring cracks, broad damp areas, salt deposits, failing facade material or work at dangerous heights may require assessment by a suitable construction or facade professional in addition to a painter.
Sources
- Benjamin Moore — How to Paint Your Home Exterior
- Sherwin-Williams — Peeling
https://www.sherwin-williams.com/homeowners/how-to/problem-solver/peeling
- Sherwin-Williams — How to Fix Exterior Paint Peeling Caused by Moisture