Exterior Painting Built for Winnipeg Winters

Concrete block and poured concrete are the most common exterior wall materials in Winnipeg's commercial inventory. The correct coating system starts with a masonry filler or block filler primer that penetrates the open pore structure of the block and provides a uniform substrate for the topcoat. On poured concrete, we use a penetrating primer that seals the concrete surface and provides a chemical bond site for the topcoat.

For masonry topcoats, we use 100% acrylic elastomeric systems for most Winnipeg exterior applications. The elastomeric designation means the coating has an elongation of at least 200% — it stretches rather than cracks as the substrate moves. This is critical on Winnipeg masonry where hairline cracks and joint mortar movement are a constant reality. A standard acrylic paint on cracked masonry will show every crack as a paint failure within one season. An elastomeric system bridges those cracks and maintains a continuous weatherproof film.

Steel cladding and metal panel systems are coated with a system appropriate to the metal type. Galvanized steel requires a zinc-compatible primer — standard oil-based or rust-inhibiting primers don't bond well to galvanized surfaces and will delaminate. Bare steel gets a zinc-phosphate or zinc-rich primer for corrosion resistance. Aluminum gets an etching primer before topcoat. Each topcoat is a polyurethane or polyvinylidene fluoride (PVDF) system for maximum UV resistance in Manitoba's high-UV summer conditions.

EIFS (External Insulation and Finish Systems — commonly called 'dryvit') require special consideration. The foam substrate is incompatible with solvent-based coatings, which will dissolve it. Only approved water-based acrylic systems can be applied over EIFS without damaging the substrate. We always verify substrate type before specifying a product — the wrong product on EIFS is not recoverable without replacing the system.

The condition of an exterior commercial building before the first brush hits it is the most important factor in how long the new coating lasts. We spend more time on surface preparation than most painting contractors — typically 40–50% of total project hours on larger exterior jobs. That time goes into power washing, caulking replacement, mechanical removal of failed paint, masonry crack repair, rust treatment on metal, and priming bare substrate.

Power washing is always the first step on exterior work. We use a hot-water pressure washer at appropriate pressure for the substrate — typically 1500–2500 PSI on masonry, 500–1000 PSI on wood, and just enough to remove loose material and algae from EIFS without damaging the foam substrate. Algae and mould on exterior surfaces must be killed before painting — painting over living organisms doesn't work; the organisms continue to grow under the film and cause adhesion failure.

Caulking at all window perimeters, control joints, penetrations, and base flashing conditions is replaced before painting rather than painted over. Painting over cracked or failed caulk locks in the failure and makes it harder to address in the future. New backer rod and sealant at every joint is the correct approach — it's a small addition to the project cost with a large impact on the system's weatherproofing performance.