How does NB’s freeze-thaw cycle affect exterior paint durability and what paint type resists it best?

New Brunswick’s freeze-thaw cycle is the single harshest force acting on exterior paint in this province, and the only product that reliably stands up to it is 100% acrylic latex exterior paint. Rigid coatings — particularly alkyd or oil-based paints — crack and chip under repeated expansion and contraction, while quality acrylic latex stays flexible enough to move with the substrate.

NB experiences well over 100 freeze-thaw cycles per year in many areas, and in some inland regions like Fredericton and Woodstock that number climbs even higher. The physics are straightforward but brutal: water infiltrates the smallest crack or gap in a paint film, freezes overnight, expands by roughly 9%, then melts and contracts again the next afternoon. Repeat this cycle dozens of times a winter and even a paint job that looked fine in October will be peeling and flaking by April. The damage is often worst on north-facing walls and soffits where moisture from ice and snow lingers longest.

The key property to look for is elongation — the ability of a dried paint film to stretch and flex without cracking. Premium 100% acrylic exterior paints from Benjamin Moore (Aura Exterior), Sherwin-Williams (Duration Exterior), or Dulux (Weathershield) have elongation ratings that allow them to move with wood, metal, and masonry through NB’s wide temperature swings, from -25°C in February to +35°C in August. These paints also breathe better than oil-based coatings, allowing moisture vapour from inside the wall to escape without lifting the paint film — an important consideration in older NB homes with incomplete vapour barriers.

Surface preparation is just as critical as paint choice. No matter how good your paint is, freeze-thaw damage accelerates dramatically when water can get behind the film. Before any exterior repaint, scrape all loose and peeling material, sand edges smooth, fill nail holes and small cracks with a quality exterior caulk rated for NB temperatures (look for caulks rated to -40°C), and prime all bare wood with an exterior oil or acrylic primer. Pay special attention to end-grain wood on trim, window sills, and boards — end grain absorbs water like a sponge and is the most common starting point for freeze-thaw failure.

If you’ve had repeated peeling problems on the same wall despite good paint choices, the cause is almost always moisture infiltrating from somewhere — a failed caulk joint, a plumbing leak inside the wall, or missing flashing above a window. A professional painter can often identify these moisture entry points during prep and recommend remediation before repainting, saving you from the same problem recurring two years later.

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