Surface Preparation & Application
Surface preparation is one of the most important stages in a durable paint system. A coating cannot reliably correct contamination, loose material, moisture problems or an unsuitable substrate.
Inspect before you prepare
Identify the substrate and existing coating. Look for chalking, peeling, rust, efflorescence, cracks, failed caulk, mildew, oil, dust, salts and signs of water intrusion. Determine whether the surface is sound and dry enough for the selected product. Investigate and correct the source of moisture before repainting.
Preparation steps
- Protect: isolate the work area and cover nearby finishes, furnishings and equipment.
- Clean: remove dirt, grease, chalk and other contaminants using a compatible method; allow the surface to dry.
- Remove unsound material: address loose paint, rust, scale and deteriorated coatings with methods appropriate to the substrate and hazard assessment.
- Repair: fill cracks and defects with compatible materials; replace or repair damaged components where needed.
- Sand or profile: create the surface condition required by the coating specification while controlling dust.
- Prime: apply the specified primer to the correct substrate and allow it to dry as directed.
- Verify: check cleanliness, dryness, surface profile and environmental conditions before coating.
Application methods
Brushes are useful for edges, trim and detailed work. Rollers efficiently cover broad areas and vary by nap and material. Airless or other spray methods can provide efficient coverage on suitable projects, but require training, masking, overspray controls, equipment checks and appropriate respiratory and skin protection.
Environmental conditions matter
Check air temperature, surface temperature, humidity, dew point, wind and ventilation against the product data sheet. Temperature and humidity affect drying and curing. Exterior work also requires attention to rain, direct sunlight and changing weather. Do not assume one product’s limits apply to another.
Quality checks
- Confirm the specified product, color, sheen and number of coats.
- Check for missed areas, runs, sags, pinholes, lap marks and uneven appearance.
- Measure wet- or dry-film thickness when the specification requires it.
- Observe the manufacturer’s recoat and cure times.
- Record deficiencies and complete touch-ups using compatible materials.
Important: Never sand, scrape or disturb old paint until the age of the building, potential lead hazards and applicable work-practice requirements have been evaluated.
