Exterior Surface Preparation: the full procedure

Wash, scrape, repair, and caulk exterior surfaces so coatings bond and stand up to weather.

• Applies to: Painters, prep crew
• Frequency: Every exterior job, before priming
• Scope: Covers washing, scraping, sanding, filling, and caulking of siding, trim, fascia, and masonry to the contracted PCA prep level. Pressure-washer safety, ladder and fall protection, and lead-safe practices on pre-1978 exteriors defer to OSHA, the EPA RRP rule, the product label and SDS, and the safety plan.

What you need

• Pressure washer
• Scrapers and wire brushes
• Exterior-grade filler
• Sandpaper
• Exterior caulk and gun
• Drop cloths and plastic sheeting

The procedure, step by step

1. Protect plants, fixtures, and grounds — Cover shrubs, walkways, AC units, and fixtures. Move furniture and grills away from the work area before anything wet starts.
2. Wash the surface — Pressure-wash or hand-wash to remove dirt, chalk, and mildew. Treat mildew before painting. Follow OSHA and the equipment manual for pressure-washer operation.
3. Let it dry fully — Allow the surface to dry 24-48 hours before coating, longer in damp conditions. Painting over trapped moisture causes blistering and peeling — verify with a moisture meter on questionable areas.
4. Scrape and sand to sound paint — Scrape peeling, cracked, or checked paint back to a tightly adhered surface and sand the edges feathered. Dull glossy spots so the new coat bonds.
5. Repair and fill — Fill holes, cracks, and damaged areas with exterior-grade filler. Replace or treat rotted wood per the agreed scope before it gets coated over.
6. Caulk joints — Caulk butt joints in siding, around windows and doors, and where dissimilar materials meet. Use exterior-rated caulk and tool the bead clean.
7. Prime bare and repaired areas — Spot-prime bare wood, masonry, and filled repairs to seal and improve adhesion. Use the primer specified for the substrate per the product label.
8. Inspect before coating — Walk the elevations and confirm everything is clean, dry, sound, and primed where needed. Wet or chalky surfaces get re-prepped, not painted.

Quality check before you finish

• Plants, fixtures, and grounds protected
• Surface washed free of dirt, chalk, and mildew
• Surface dried 24-48 hours and moisture verified
• Loose paint scraped to sound, edges feathered
• Repairs filled with exterior-grade product
• Joints and penetrations caulked with exterior caulk
• Bare and repaired areas spot-primed

This is a free, source-anchored standard operating procedure (SOP) you can print and hand to staff. It documents the work sequence for a Painting business — not safety or regulatory rulings, which defer to the cited authorities, the applicable code, and your own health-and-safety plan. Open the tool above to print it, toggle ink-saver, or (with a free ToolFluency Business account) edit it to match your own workflow.

Sources

• Sherwin-Williams Exterior Surface Preparation (sherwin-williams.com)
• Painting Contractors Association (PCA P14) (pcapainted.org)
• OSHA (osha.gov)