Exterior Painting in Toronto & the GTA

When can the outside of a house be painted in the GTA?

Late May to September is the dependable window in the GTA, and mild, dry days in April and October can work too. The paint's data sheet sets the limits, not the calendar.

Each painting day has to pass three checks. The label's minimum temperature has to hold for the wall and the air until the paint has dried, and that includes the night after. The wall must be dry, with no rain due for a few hours. It must also stay warmer than the dew point, which is why fall painting days start late and end early.

Our posts on which months suit exterior painting and how cold is too cold to paint outside give the temperatures and the weather month by month.

What prep does a house exterior need before painting?

It needs washing, scraping, sanding, spot-priming and caulking, in roughly that order. The wall has to be fully dry before any primer or paint goes on.

Step	What it involves
Wash	Dirt, chalk and loose grime come off with a scrub brush or a pressure washer. Mildew gets a diluted bleach wash, as paint makers advise.
Dry	One major paint maker suggests a day or so after a pressure wash, so water driven behind the siding can work its way out.
Scrape	Loose and peeling paint comes off, back to paint that is holding firmly.
Sand	Scraped edges are sanded smooth, or feathered, so they don't show through the new paint.
Spot-prime	Bare wood and repaired spots get primer before the finish coats, a step called spot-priming.
Caulk	Open joints around windows, doors and trim are sealed after priming. The overlaps of lap siding stay open, so moisture can escape.

A crew lead checks every surface for repairs, soft or rotten wood included, from your photos or on site. Your written quote then spells out the prep for your house.

Older homes need one more check before any scraping starts. Health Canada says a home built before 1960 probably has lead-based paint, and one built between 1960 and 1990 may have it on the exterior. It warns against sanders, heat guns and torches on lead paint, because they create toxic dust and fumes. Have old paint tested before anyone scrapes or sands it. Health Canada's page on lead-based paint explains how.

How long does exterior paint last?

On wood siding, a primer and two good topcoats can last up to 10 years. That figure comes from a Purdue University guide written with the U.S. Forest Products Laboratory, which gives a single topcoat four to five years.

Treat it as a rough guide, because the house decides the rest:

• Sun and rain. The same guide says the south and west sides of a house usually wear first.
• Shelter. Porch ceilings and roof overhangs weather slowly, and it advises repainting them less often than the rest of the house.
• Prep and paint. Paint on a clean, sound, primed surface outlasts paint laid over chalk or peeling. The paint line matters too, as our guide to premium and contractor-grade paint explains.

Exterior paint wears by fading, chalking and slowly eroding. Repainting while the old coat is still sound means less scraping than waiting until it peels.

Do you need a permit to paint the outside of your house?

Usually not: painting is cosmetic work, and Ontario municipalities don't normally require a building permit for it. Two cases are worth checking first: heritage properties and condominiums.

A property designated under the Ontario Heritage Act, or inside a heritage conservation district, needs approval for many exterior changes. Each district's plan lists the minor work that needs no heritage permit. Ontario's guidance on district plans gives painting, using the exact materials and colours, as an example of maintenance. Toronto's district guidance also says routine maintenance like painting needs no heritage permit.

A new colour, or paint on brick that has never been painted, may not count as maintenance. Ask your municipality's heritage planning staff before you commit to either.

In a condominium townhouse, ask the condo board before painting outside. The Condominium Authority of Ontario says most owner changes to the common elements need the board's approval.