A board member walked me around the back of their building to show me “a bit of rust” on the exit doors — the bottoms of four steel frames were already rusting through
A board member at a mid-rise asked me to look at the steel exit doors around the back and sides of the building before winter. He called it a bit of rust. When we walked them, the doors and frames looked fine at eye level, but the bottom 15 to 20 cm of every frame was bubbled, flaking and orange, and on four of them I could push a screwdriver-sized soft spot in the steel at the base. Salt, snow piled against the door, and a coat of paint rolled over the rust every few years had done it. This post covers why exit doors rust from the bottom up, what a real repair involves, and when to do it. It’s for condo boards and property managers, not homeowners.
1. Exit doors rust from the bottom up, and it’s mostly salt
The bottom of a steel door frame sits right where snow piles up, where the plow and the shovel push slush, and where salted water pools on the step. All winter it stays wet and salty. Once the paint at the base gets chipped by a shovel or a boot, water gets under it and the steel starts rusting under the paint film, where you can’t see it.
By the time it shows as bubbles and orange streaks, the rust has usually travelled further up under the paint than it looks. The doors that see the least traffic are often the worst, because nobody clears the snow away from them.
What to look at: Walk every exit door, not just the main entrances. Look at the bottom of the frame on both sides and the bottom edge of the door itself. That’s where it starts.
2. Painting over rust just hides it for a season
The most common thing I see is a fresh coat of paint rolled right over the rust, sometimes the same colour, sometimes not quite. It looks tidy in October. By spring the bubbles are back, because the rust under the paint kept growing. Paint doesn’t stop rust. It only slows it down when it’s on clean, sound steel.
I explain the same problem on other steel around a building in repainting exterior steel with rust.
What to look at: Look for paint bubbles that come back in the same spot every spring. That’s rust under a coat that was put on without proper prep.
3. The repair: get back to clean steel, then a coating system
For a door frame that’s rusted but still solid, the work is straightforward. I scrape and wire-brush or grind off all the loose rust and failing paint until I’m back to sound steel, feather the edges, and spot prime the bare metal with a rust-inhibiting metal primer the same day so it doesn’t flash rust. Then the whole door and frame get two finish coats of an exterior-grade industrial enamel, not a regular house paint.
Where the steel at the base is soft or has holes, painting isn’t the fix. That section needs to be repaired or replaced by a door or metal trade first, and then I coat it. I’ll tell you which frames are in that state when I walk them.
What to look at: Ask whether the quote says “scrape and paint” or spells out rust removal, metal primer and the finish system. The second one lasts.
4. Timing: before the snow, or right after the thaw
Primer and enamel need dry steel and temperatures above the minimum on the product label, which in Ottawa usually means getting exterior steel done by late October or waiting until April or May. I’d rather do a handful of the worst doors now, before the salt starts, than leave them through another winter. The rest can go on a spring list. I cover how salt season hits building entrances in lobby entrance repaints before salt season.
What to look at: If you can’t get it done this fall, at least ask the snow contractor to keep the exit doors clear and avoid piling salted snow against them.
5. Put exit doors on a short repaint cycle
Exit doors take more abuse than most of the building’s painted steel, so they shouldn’t wait for the big exterior repaint every 8 to 10 years. A quick inspection every spring and a touch-up cycle every 3 to 5 years keeps small rust spots from turning into frame repairs. It’s a small line item in the reserve fund compared to replacing a frame.
What to look at: Make a list of every exterior steel door with its condition and photo. It takes an hour and gives the board something to plan from.
What to do if you’re seeing any of this
If the bottoms of your exit doors or frames are bubbling or rusting, I’ll walk the building with you and tell you which ones need proper rust removal and a coating system, which can wait for spring, and which have gone soft and need a metal repair first. You get a scope and a number the board can approve. I work with condominium corporations and property managers across Ottawa — Kanata, Nepean, Barrhaven, Orleans, Westboro and Stittsville — on exterior steel and protective coatings. Call 613.325.3011 or email yasir@heims.ca.
— Yasir, HEIMS Construction
HEIMS Construction is an Ottawa-based commercial painting and drywall contractor serving condominium corporations, property managers and institutional clients across the Ottawa area. Fully licensed and insured, with $5M commercial general liability coverage.