Priming is often seen as an extra step, but professional painters stress that it’s an investment that saves homeowners money in the long run. A quality primer creates a uniform surface that allows paint to adhere properly, reducing the number of coats needed. Without it, paint can soak unevenly into surfaces especially porous ones like new drywall or bare wood leading to patchy coverage and the need for costly touch-ups.
Primer also blocks stains, tannins, and old paint colors from bleeding through, which prevents rework and ensures the topcoat looks clean and vibrant. On tricky surfaces such as metal, glossy finishes, or masonry, specialized primers help paint bond better, reducing the risk of peeling or chipping later.
By extending the lifespan of a paint job and lowering maintenance costs, priming ultimately protects both the finish and the homeowner’s budget. Skipping primer may seem like a shortcut, but it often results in higher expenses down the line
Priming outside in the GTA has about a month left this year, and the number that matters is the overnight low, not the afternoon high. Sherwin-Williams’ late-season painting guide says its exterior lines are formulated down to 35°F (about 2°C), but warns about the specific trap of days above 50°F (10°C) with nights below 35°F: the coat goes on fine and then stops coalescing after dark. It also notes that dew forms on almost everything at sunset and seeps into uncured paint, which shows up later as surface staining and adhesion problems. Benjamin Moore’s temperature guide gives the same 35°F floor and adds that the surface should be at least 5°F above the dew point when you apply.
So for exterior primer on bare wood or trim this month: check the Environment Canada forecast for the night, not just the day, and stop by mid afternoon so the primer has a few hours before dew. Interior priming is unaffected and is the better job to book for October and November.
On cost, the argument in the first post holds up on current shelf prices. Home Depot Canada lists Kilz PVA drywall primer at $22.97 for 3.79 L (300 to 400 sq ft per can) and Zinsser Bulls Eye 1-2-3 at $49.97 for 3.78 L (up to 400 sq ft). A can of PVA on new drywall is cheaper than the extra coat of finish paint it saves.
Is anyone here priming exterior wood right now, and what overnight temperatures are you seeing on the forecast?
