Exterior Painting Checklist for Homeowners

Phase 1: Pre-Job Inspection

Before anyone puts a brush on your house, a thorough inspection needs to happen. If you're hiring a painter, this is the quote walkthrough. If you're DIY-ing, walk the full perimeter yourself and check for the following:

1. Check for soft or rotted wood. Press a screwdriver or key against the trim boards, sill plates, fascia boards, and window casing. Sound wood is firm. Soft, spongy wood means rot — and it needs to be repaired or replaced before painting. Paint over rot is just cosmetic delay; the rot continues underneath.
2. Identify all peeling, cracking, or bubbling paint areas. Mark them or take photos. These areas require the most prep attention: scraping to the bare substrate, sanding smooth, and priming before repainting.
3. Inspect all caulking joints. Check around every window and door frame, where siding meets trim, and at the base of any wood elements meeting masonry. Failed caulking — gaps, cracks, or sections that pull away easily — lets water behind the siding. All of it needs to be replaced before painting.
4. Check for mould or mildew. Black or green discolouration on north-facing walls and in shaded areas is often mildew. It needs to be cleaned with a mildewcide solution before painting — painting over mildew just traps it and it grows back through the new paint.
5. Assess siding for nail pops and gaps. Nail heads that have worked their way out get re-set and filled. Gaps between siding boards get caulked.

Phase 2: Weather Planning

1. Check the extended forecast. Don't start an exterior job if rain is forecast within 24–48 hours. For Ontario, use the Environment Canada hourly forecast — it's more reliable for day-specific planning than apps.
2. Confirm overnight temperatures. Paint needs to be applied when temperatures will stay above 10°C for at least 24 hours after application. In spring (April-May) and fall (September-October) in Toronto, nighttime temperatures can drop below this threshold. Check forecast lows, not just daytime highs.
3. Plan for humidity. Don't apply exterior paint when relative humidity is above 85%. High humidity slows cure and can cause adhesion problems.
4. Schedule buffer days for weather delays. Any exterior job in Ontario should build in at least one or two buffer days for unexpected weather. This isn't optional — it's realistic planning.

Phase 3: Surface Preparation

This is the most labour-intensive phase and the one that most determines how long the paint job lasts. Don't rush it.

1. Power wash the entire exterior. Use appropriate pressure for the substrate — lower pressure for wood, higher for concrete or masonry. Remove all dirt, mildew, chalking paint, and surface contamination. Allow to dry completely — for wood siding, this typically means 48–72 hours before painting depending on weather conditions.
2. Scrape all peeling and loose paint. Any paint that can be removed by hand scraping needs to come off. The goal is a solid, stable paint surface everywhere. Painting over loose paint just means the new paint will peel with it.
3. Sand scraped and rough areas smooth. The transition from intact paint to bare substrate needs to be feathered smooth. You can see and feel a sharp edge at the paint perimeter — and so will the new paint if it isn't addressed.
4. Replace failed caulking. Remove all old, cracked caulking before applying new. New caulk applied over old usually fails faster than starting fresh. Use a paintable, exterior-grade polyurethane or siliconized acrylic caulk.
5. Make any wood repairs. Fill small soft spots with wood epoxy filler. Replace boards or sections that are too far gone. Get this done before any primer or paint goes on.

Phase 4: Primer Application

1. Prime all bare wood. Any area sanded or scraped to bare wood gets a coat of exterior oil or water-based primer before finish coats. Bare wood absorbs paint inconsistently — primer seals it and gives the finish coat a uniform base.
2. Prime all repaired areas. Epoxy filler, patched knots, and any surface where the old paint was completely removed needs primer.
3. Consider full-surface primer on severely degraded substrates. If you're painting a surface that had significant peeling across large areas, a full prime coat on all surfaces before the finish coats will dramatically improve adhesion and longevity.
4. Allow primer to fully dry before applying finish coats. Follow manufacturer's recommendations — typically 24 hours for oil primer, shorter for water-based.

Phase 5: Paint Application and Cleanup

1. Protect landscaping and hardscape. Cover plants, shrubs, and any surfaces that shouldn't get paint. Move vehicles. Overspray travels further than people expect on a windy day in Scarborough or Etobicoke.
2. Apply finish coats in the right sequence. Work top to bottom (soffits and fascia first, then upper siding, then lower courses), and follow the shade to avoid applying paint on sun-heated surfaces.
3. Apply two full coats of finish paint. Allow appropriate dry time between coats (at least 4 hours, ideally 24 for oil-based). Two coats of quality exterior paint is the minimum for a durable result.
4. Inspect each elevation as you finish. Walk the perimeter after each coat and look for holidays (missed spots), runs or sags, and areas of thin coverage. Fix while the paint is still fresh.
5. Clean up thoroughly. Remove all masking, protection material, and equipment from the property. Check the site for dropped brushes, paint-contaminated rags, or anything that shouldn't be left behind.
6. Final walkthrough with the homeowner. Any legitimate contractor should do a final walkthrough with you before considering the job complete. If anything doesn't look right, say so immediately — it's much easier to address before the crew leaves than after.