Ceiling Leak? Causes, What To Do and Who To Call

Most ceiling leaks in two-storey GTA houses come from the bathroom directly above. Drains only leak when water is running through them, so a stain that grows after showers but stays dry otherwise is almost always a drain, grout, caulking or shower pan problem rather than a supply pipe.

You can usually narrow it down yourself by testing one fixture at a time. Run the bathroom sink for a few minutes, then wait and watch the ceiling. Do the same with the tub faucet only, then the shower head with the curtain held so water only hits the tub, then a toilet flush. The fixture that brings the drip back is your source.

A supply pipe is pressurized all the time, so it leaks whether or not anything is running. If you shut off the main and the drip slows to nothing over the next hour, a supply line is the likely cause. Toronto homeowners can also check hourly use in MyWaterToronto: water use overnight while nothing is running is a sign of a hidden leak.

A roof leak usually shows up on the top-floor ceiling and only during or after rain or melting snow. The most common entry points are not the middle of the shingles but the places where the roof is interrupted: flashing around chimneys, plumbing vent boots, skylights, roof vents, and valleys where two slopes meet.

If you can safely get into the attic during or right after a rain, look for wet roof boards, drips, or dark staining on the wood and trace it upward. Water often enters well above where it lands, then runs down a rafter. A roofer will need to repair the entry point; until then, a professional tarp can stop more water getting in.

GTA winters add two causes that look exactly like a roof leak from inside. An ice dam traps meltwater at the eaves and pushes it under the shingles, so stains appear close to exterior walls during thaws. Our guide to an ice dam leaking into your house covers what to do and how to remove the ice safely.

Frost in the attic forms when warm, moist air from the house leaks into a cold attic and freezes on the underside of the roof. On the first mild day it melts all at once and drips through the insulation, often in several spots and around pot lights and bathroom fans. Our guide to frost in the attic explains how to tell it apart from a roof leak. Both come down to the same root cause: warm air escaping into the attic.

Water dripping from a bathroom exhaust fan in cold weather is one of the most common ceiling leak calls we get in winter, and it usually is not a roof leak. Warm, humid shower air travels up the fan duct through a cold attic, condenses inside the duct, and runs back down onto the fan housing and the ceiling around it.

The usual fixes are insulating the duct along its full length in the attic, making sure it slopes toward the outside so condensation drains out rather than back, keeping it as short and straight as possible, and running the fan long enough after a shower to clear the moisture. A stain around the fan grille that comes back each winter is a strong sign this is the cause.

In Toronto and Mississauga condos, many suites are heated and cooled by a fan coil unit tucked into a closet or a ceiling bulkhead. These units collect condensation in a drain pan, and when the pan or its drain line clogs, water overflows onto the ceiling or into the closet below. Leaks that show up in summer, while the air conditioning is running, often point here.

The other common source is the unit directly above: a dishwasher or washing machine hose, a toilet, a tub overflow, or a balcony drain. Because you cannot see into the space above a condo ceiling, building management needs to inspect the suspected source unit as quickly as possible, and the section below covers how responsibility is usually decided.

Report the leak to building management or the superintendent immediately, then follow up in writing with photos. Management can get into the unit above, shut off water to it, and arrange repairs to the source.

Who pays is set by Ontario's Condominium Act, your corporation's declaration and by-laws, and the insurance policies involved. Under section 105 of the Act, the deductible on the corporation's insurance is normally a common expense. The corporation can charge it back to the owner of the unit where the water came from, capped at the lesser of the deductible and the cost of repairing that unit, when the damage was caused by an act or omission of the owner or someone living in or visiting the unit. Many corporations also pass a by-law that extends those chargebacks to other situations.

In practice, the corporation's policy usually covers the standard unit, while your own condo policy covers your upgrades, belongings, and possibly a deductible chargeback. Call your broker early, and ask for any chargeback decision and the by-law it relies on in writing.

Under Ontario's Residential Tenancies Act, the landlord is responsible for keeping the rental unit in a good state of repair, which includes fixing the leak and repairing the ceiling. Tell your landlord right away, then confirm it in writing with photos and the date. Your tenant insurance is what covers your own damaged belongings, so report it to your insurer as well.

Mould can begin growing within 24 to 48 hours of materials getting wet, and the inside of a ceiling cavity is dark, still and slow to dry. Our guide on how long mould takes to grow after water damage explains the timeline. When a ceiling has to come out, the damaged section is removed, the cavity is dried with structural drying equipment, and then the area is rebuilt with drywall repair.