A property manager had the same bathroom ceilings painted three winters in a row — by February the black spots were back every time, and the paint was never the problem
A property manager for a rental mid-rise called me in last spring about bathroom ceilings. Every fall the mildew complaints started, every winter her painter rolled a fresh coat over the spots, and by February the black specks were back in the same corners. I looked at a dozen of those bathrooms with her. The paint was doing what paint does. The mildew had never been killed, the fans were barely moving air, and the ceilings had the wrong paint on them. This post covers why bathroom mildew comes back through paint and how to stop paying for the same ceiling every year. For property managers and condo boards, not homeowners.
1. Paint covers mildew, it does not kill it
Mildew is a growth, not a stain. Roll paint over it and it keeps growing underneath, then comes back through the new film, usually in the same spots and often within a few weeks of the first cold snap. On some of the ceilings I looked at, you could see the same grey shadow under three coats of white.
It has to be killed and removed first. Wash the ceiling with a bleach-and-water solution, commonly about one part household bleach to three parts water, or a mildew wash made for the job. Let it sit, rinse it, and let the ceiling dry for a full day before anything goes on it. Never mix bleach with cleaners that contain ammonia, and keep the window open and the fan running while you do it.
If you are not sure it is mildew, put a drop of the bleach solution on a dark spot. Mildew lightens within a minute or two. Dirt does not.
What to look at: Do the bleach-drop test on one spot in a unit with a complaint. If it lightens, ask your painter in writing how they kill mildew before they prime, and how long they let the ceiling dry.
2. Why it starts every October
The pattern follows the heating season. Windows close, a hot shower fills the room with moist air, and that air finds the coldest surface in the room. In a bathroom that is usually the ceiling corner along the outside wall, or the whole ceiling on a top floor. Water condenses there, sits on the paint for hours, and mildew starts.
That is why the same units call every year. In the building I walked, almost every complaint came from top-floor units and corner units on the north side. Those ceilings run colder through an Ottawa winter, and the paint on them stays wet the longest.
What to look at: List last winter’s mildew complaints by unit number. If they line up in the same stacks and on the top floor, it is a building pattern, and it should be handled as one job.
3. The fan decides whether the new paint lasts
Bathroom fans are not a painting item, and I tell property managers that up front. But repainting a ceiling over a fan that does not work is paying for the same job next year. In that building, more than half the fans I checked could not hold a single square of toilet paper against the grille. Some were clogged with lint. Others were most likely ducted badly or disconnected somewhere nobody could see.
A working fan, run during the shower and for about 20 minutes after, clears most of the moisture before it settles on the ceiling. A fan that only makes noise clears none of it.
What to look at: Hold one square of toilet paper to the fan grille with the fan running. If it does not stay pinned, have the fan and its duct looked at by your mechanical or electrical contractor before the painter is booked.
4. Bathroom ceilings need a different paint than the living room
Most of the ceilings I looked at had been painted with the same flat ceiling white as the rest of the unit. Flat paint is the right choice for a living room ceiling because it hides flaws. In a bathroom it is the wrong one. It is porous, it holds moisture, and it cannot be wiped clean.
What works is a stain-blocking primer over any shadow left after cleaning, then two coats of a paint made for bathrooms, with a mildew-resistant additive, in a satin or similar finish that can take a wipe. Here is how sheen affects washability in rooms that see heavy use. If the stain is brown and ring-shaped rather than black and speckled, it is a leak, not mildew, and it needs a different fix.
Fresh paint also needs time before it gets steamed. In occupied units I ask the tenant to run the fan, leave the door open, and skip the shower for as long as the label asks if they can.
What to look at: Check the unit paint standard on file. If the bathroom ceilings are listed as the same flat white as the rest of the unit, that is the first line to change.
5. Fix it as one building job, in the fall
Painting bathroom ceilings one complaint at a time, in January, is the most expensive way to do it. The painter comes back for each unit, the ceilings never dry properly in the middle of winter, and the fans never get looked at because nobody connects the calls.
The better approach is one job: test and fix the fans in the affected stacks, then clean, prime and repaint those ceilings in a single visit, early in the heating season or during turnovers. Then write the bathroom paint into the unit standard so the next turnover uses the right product.
What to look at: Before the end of October, pull the list from section 2, price the affected bathrooms as one scope, and book the fan checks first.
What to do if you’re seeing any of this
If the mildew calls are starting again this fall, a walk through a handful of the affected units usually shows whether it is the cleaning, the fan or the paint, and most of the time it is all three. I work with property managers and condo boards across Ottawa — Kanata, Nepean, Barrhaven, Orleans, Stittsville and Westboro — to clean, prime and repaint bathroom ceilings with the right product, and to write it into the unit standard so it holds. 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.