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A property manager called me out to a mid-rise last spring because the paint on the south wall was peeling off in sheets barely two years after it had been done. She was sure she’d been sold cheap paint. I spent an hour on a ladder and in the mechanical room and found the real story: water was getting in behind the wall and pushing the coating off from the inside. The paint was fine. Everything around it wasn’t.
That’s the pattern I see over and over. Exterior paint should hold up for 7 to 10 years on most Ottawa buildings. When it fails after two or three, it almost always traces back to one of five causes — and none of them is the paint being “cheap.” If you’re staring at peeling siding, blistering trim, or chalky stucco on a building you painted not long ago, here’s what I’d be checking.
1. Moisture coming from the wrong side
This is the first thing I check, because it’s the #1 failure mode I run into and the one most people get wrong.
Paint can shed rain. It cannot shed water that’s already behind it. When a wall is wet from the inside — a leaking flashing above, a missing vapour barrier, a roof or window detail letting water track sideways — that moisture pushes outward and lifts the paint off the substrate in sheets. On that mid-rise, the giveaway was exactly this: the paint was peeling in big strips off the upper part of the wall, not flaking in little chips. When I see that, I stop thinking about paint and start hunting for where the water is getting in.
What to look at: roof-wall flashings, window head flashings, where two materials meet (siding against brick, for example), and any caulking older than 8 years.
2. The prep wasn’t done
A good paint job is 70% prep and 30% paint. The trouble is the prep is invisible once it’s finished — which is exactly why it’s the first thing cut when a job is bid too low, and usually what I’m looking at when a coating fails early.
The three prep steps I find skipped most often: pressure washing to get chalky old paint, dirt, and pollen off (skip it and you’re painting onto loose material that drags the new coat off when it lets go); a proper biocide for mildew rather than just bleach (bleach pulls the colour out of mildew but doesn’t kill the spores, so it grows back through the new coat within a year); and spot-priming bare wood, rust, and patches (bare substrate drinks paint differently than primed, so you get visible flashing and early failure right where the prep was thinnest).
What to look at: was the surface washed within 48 hours before painting? If a crew pulls up to your building with rollers and no pressure washer, you already have your answer.
3. Wrong coating for the substrate
The version of this I run into most is latex rolled over old oil-based paint with no bonding primer. It cures fine for a few months, then starts to fish-eye, blister, and lift off in patches as the seasons cycle.
Others I’ve pulled apart: interior-grade paint used outside (the binders aren’t UV-stable), masonry paint on EIFS (wrong elasticity), and “all-in-one” paint-and-primer products on chalky old surfaces (whatever the can says, it isn’t a real primer).
What to look at: does your contractor actually know what’s on the wall right now? If they can’t tell you and won’t test it, that’s a red flag. A 30-second xylene rub tells me in a minute whether I’m dealing with oil or latex underneath.
4. Applied in the wrong weather
Paint has a tighter weather window than most people expect, and this is the one I can’t see after the fact — so I ask how the last job was scheduled. For most acrylic exterior paints the rough rules: air temperature between 10°C and 30°C across the whole curing window, not just the moment of application; surface temperature in the same band (a south-facing wall in direct sun can run 15°C hotter than the air); no rain forecast within at least 4 hours, ideally longer; and a dew-point spread of at least 3°C, because if the substrate is colder than the dew point you’re painting onto condensation you can’t see.
A crew that rolls a coat at 7am on a damp May morning, or finishes one at 6pm in October as the temperature drops, is setting the job up to fail. It usually shows up the following spring as adhesion loss on the lower courses, where dew sits longest.
5. The building moves and the paint can’t
Buildings expand, contract, settle, and vibrate. Wood siding moves a lot, stucco moves a little, EIFS moves differently than brick. The coating has to be elastic enough to keep up.
When I see hairline cracks running dead straight along board edges, or “alligator” cracking across a stucco surface, the coating is failing because it’s too brittle for the movement underneath. The right system for the substrate solves it — but the wrong product can’t be fixed by piling on a thicker coat.
What to look at: if the building has had movement cracking patched and painted over before, the next coat needs a high-build, elastomeric system, not a repeat of the last paint.
What to do if you’re seeing any of this
If you’ve got peeling, blistering, chalking, or cracking on a building you manage, the question I’d ask isn’t which paint to use next time. It’s what’s actually failing — the coating, the prep, the moisture management, or the substrate? That’s what changes the scope of work and the budget.
I do free assessments for property managers on buildings across Ottawa — Kanata, Nepean, Manotick, Orleans, Barrhaven, Stittsville, Westboro, and everywhere in between. I’ll tell you what’s failing and what’s not. If it’s a simple recoat, I’ll say so. If there’s a moisture issue behind the wall that needs solving first, I’ll say that too — and I won’t recoat over an unresolved problem just to close a job.
Call 613.325.3011 or email yasir@heims.ca to set up a walkthrough.
— Yasir, HEIMS Construction
HEIMS Construction is an Ottawa general contractor serving property managers, condo boards, and institutional clients across Ottawa and surrounding areas including Kanata, Nepean, Manotick, Orleans, Barrhaven, Stittsville, and Westboro. We’re members of BOMA Ottawa, the Ottawa Construction Association, BOMA Canada, Alcumus, and the CCI Eastern Ontario Chapter.