How Cold Is Too Cold for Outdoor Painting?

How Cold Is Too Cold for Outdoor Painting?

Even if it’s warm while you paint during the day, lower nighttime temperatures can ruin a good paint job  

Now that it’s cooler, in many parts of the country you can tackle those big outdoor home improvement jobs without breaking a sweat. It’s a great time to paint the exterior of your house, But get moving. Water-based exterior paint requires certain conditions to cure properly, or you’ll be repainting your house sooner than you planned.

“It should be at least 10° C when applying the paint and shouldn’t drop below 0° C at night for several days after,” says Rico DePaz, the paint pro at Consumer Reports. The paint needs several days to cure, and as the temperature dips, dew can form on surfaces and the water in the paint evaporates too slowly.

Even if it’s toasty during the day, if temperatures drop too low at night the paint won’t form a good film. That affects how the paint holds up over time, including how well it resists cracking, according to the Paint Quality Institute. Durability aside, the colder temperatures and moisture on the surface can result in staining or mildew.

Some manufacturers now claim that certain paints will cure in temperatures as low as 2° C. You still have to keep an eye on the nighttime temperatures and the extended forecast. Check the label on the paint can for instructions on temperature ranges, and follow Rico’s tips for nailing the job.

Prep Before You Paint

  • Protect plants. Cover plantings, your air conditioner(s), and exhaust vents with drop cloths. Tie back shrubs and tree limbs.
  • Scrub, then patch. Dirt, mildew, and chalky old paint prevent fresh paint from adhering properly. If your house was built before 1978, it may be coated in lead paint. (See CR’s step-by-step guide for how to test for lead paint with a DIY lead test kit.) In that case, you’ll need to use a certified lead abatement contractor to prep the surface. Otherwise, scrub the surface with a wire brush or scrub pad, or very carefully with a pressure washer, and clean with a detergent such as Red Devil TSP.
  • Remove mildew. Mix a solution of chlorine bleach and water or buy a commercial cleaner. Wearing gloves, a mask, and eye protection, scrub the mildew away. Scrape out rotted areas and fill them with wood filler, then sand smooth. Allow to dry for several days before painting.
  • Caulk and prime. Scrape away dried and cracked caulk around windows, doors, and trim. Apply fresh acrylic caulk where needed. Prime bare wood using the primer recommended by the paint manufacturer, or skip priming by using a high-performing self-priming paint.
  • Replace cracked or rotted boards. Water might seep in if you just fill and repair cracked or split boards.

What Paint is Best? 

Check our buying guides for paint and wood stains for more information.

Contact SOS Property Rescue for questions and to book a consultation with us at: 604-251-5931.

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