How do I prevent paint from cracking around door frames in my Ottawa home?

Cracking paint around door frames is one of the most common complaints Ottawa homeowners deal with, and it almost always comes down to two culprits: movement and moisture. The good news is that both are preventable with the right approach.

Ottawa's climate is particularly hard on door frame paint because your home is constantly expanding and contracting. In winter, forced-air heating drops indoor humidity to 15–25%, causing wood trim to shrink. Come spring and summer, humidity rises and the wood swells back. Do this for several years and the paint film — especially if it was applied too thickly or without proper primer — simply can't keep up with the movement. The result is those characteristic hairline cracks along the joint between the door casing and the wall, or along the mitered corners of the frame itself.

The fix starts with proper prep, which is genuinely 80% of the job here. First, scrape and sand away any loose or cracked paint back to a stable edge. Don't just paint over cracked paint — it will crack again within a season. Once you've got a clean surface, inspect every joint where the casing meets the wall and where mitered corners meet each other. These joints need to be filled with a paintable, flexible acrylic latex caulk (not silicone — paint won't bond to silicone). A product like DAP Alex Plus or Tremco Dymonic works well for this application. Apply a thin, consistent bead, tool it smooth with a wet finger, and let it cure fully before painting — typically 24 hours.

For primer, don't skip it. A quality bonding primer like Zinsser Bulls Eye 1-2-3 or Benjamin Moore Fresh Start will give your topcoat something to grip. For the topcoat on trim, consider a hybrid alkyd paint like Benjamin Moore Advance or Sherwin-Williams Emerald Urethane Trim Enamel. These products cure to a harder, more flexible film than standard latex — exactly what you need on surfaces that move seasonally. Expect to pay $75–$95 per litre for these premium trim products, but the durability difference is significant.

One important warning: if your home was built before 1978, test for lead paint before sanding or scraping. Ontario Regulation 278/05 requires proper handling and containment if lead is present — this isn't a step to skip.

If the cracking is severe, the frames are damaged, or you're dealing with multiple door frames throughout the house, it's worth having a professional assess whether there's an underlying structural movement issue before repainting. You can browse painting contractors serving Ottawa through the Ottawa Construction Network directory at justynrookcontracting.com/directory if you'd like a professional opinion on the scope of the work.