Exterior Painting Prep Guide

Exterior paint preparation begins with a thorough cleaning. Use a pressure washer with a 1,500–2,000 PSI setting and 40-degree tip to remove dirt, chalk, and loose paint. For mildew (common on north-facing sides), apply a bleach-water solution (1:3) and let sit 15 minutes before rinsing. Hold the nozzle 12–18 inches from the surface—too close and you damage wood. After drying 48 hours, scrape all loose and peeling paint with a 3-inch putty knife or paint scraper. Pay special attention to window sills, door frames, and bottom edges of siding where moisture collects. Use a wire brush for stubborn areas. Sand the scraped edges with 80–100 grit sandpaper to feather the transition between bare and painted areas. Vacuum or blow off all dust before proceeding.

Before painting, repair all damage to the surfaces. Fill nail holes and small dents with exterior spackling. Replace rotted wood sections (see the Siding Repair Guide for techniques). Remove and replace damaged caulk around windows, doors, and trim joints. Cut the old caulk out with a utility knife rather than painting over failing caulk. Apply new 100% acrylic latex caulk in a smooth, continuous bead. Tool the caulk with a wet finger or caulking tool for a professional finish. Wipe excess with a damp rag. Caulk all gaps: where siding meets trim, corners, window and door frames, and the joint between the foundation and siding. Proper caulking seals out moisture and insects and prevents future paint failure.

Primer is essential for areas where bare wood is exposed. Apply an exterior-grade acrylic primer to all scraped areas and new wood. Use a stain-blocking primer if you are covering dark colors or if the wood has tannin bleed (cedar, redwood). If the old paint is glossy, sand it dull with 120-grit sandpaper or apply a bonding primer. For metal surfaces (gutters, downspouts), use a rust-inhibiting metal primer. For bare wood, apply primer to all edges and end grain—these areas absorb the most moisture. Allow primer to dry fully (per manufacturer directions—typically 4–24 hours). A properly primed surface ensures maximum adhesion and prevents the old paint color from bleeding through.

Choose 100% acrylic exterior latex paint for the best durability and color retention. Satin or semi-gloss sheens work well for trim; flat or satin for siding. Buy enough paint for two coats—the second coat is where durability comes from. Apply paint on dry days between 50–85°F, avoiding direct sun on hot surfaces. Start at the top of the house and work down. Paint the edges (trim, windows, doors) first with a brush, then fill in the large siding areas with a roller or sprayer. Maintain a wet edge to avoid lap marks. Allow the first coat to dry 4–6 hours before the second coat. Two coats of quality paint applied over proper preparation last 7–10 years on siding and 3–5 years on trim.

Exterior painting involves ladders, heights, and chemicals. Use a stable ladder on level ground—extend at least 3 feet above the roof edge. Use ladder stabilizers to prevent contact with gutters. Wear safety glasses and a dust mask when scraping and sanding. For older homes (built before 1978), test paint for lead before sanding or scraping—lead paint requires special handling. Set up drop cloths over landscaping and walkways. Cover plants with plastic sheeting (remove after each day to prevent overheating). Have a first aid kit accessible. Never work alone on a ladder—have someone spot you for tasks over 8 feet. Proper safety prevents the injuries that turn a painting project into a costly disaster.