Ceiling leaks can signal the presence of a larger problem lurking in the attic, roof, or upper floors. Identifying the ceiling leak, tracing it to its origin, and stopping it must all be done before repairing the ceiling.
Signs of a Leaking Ceiling
A ceiling leak can be as obvious as water dripping from the ceiling onto the floor, or it can manifest itself in ways that are more difficult to detect: musty smells, ceiling fixtures full of water, or infestations of insects. Most ceiling leaks are persistent, not one-off or isolated problems. The leak does pass through the ceiling, but it can also continue and drip down walls.
Bubbled ceiling paint is often a sign of a ceiling leak. Interior latex paint is sturdy enough to hold in water, much like a balloon. So, the water passes through the ceiling drywall or plaster and is held back by the paint layer.
Dark or Rancid Water
The leaking water is often dark-colored and it will stain white or light ceilings or walls. It may smell mildewy or even rancid. Or, the water might be clear and odor-free.
Events Causing Leaks
A leaking ceiling can often appear after it rains or snows or with activities in the home, such as flushing a toilet or taking a shower. Ceiling patches may even indicate previous ceiling leaks.
Ceiling condensation is not a ceiling leak, though the two can be confused for each other. In ceiling condensation, steam collects on the ceiling and forms water drops, which give the impression of a ceiling leak. Ceiling condensation is the result of poorly ventilated bathrooms, kitchens, or laundry rooms.
Investigating and stopping ceiling leaks can place you in the way of any number of household dangers: lead-based paint in the ceiling; asbestos in the ceiling insulation or on pipe wrap; or black mold behind drywall or in insulation. Climbing ladders into attics or onto roofs may cause you to fall. Falls are a leading cause of household injuries or death.
Examine Home for Internal Ceiling Leaks
Mark Pooled Water
Start at the water’s end-point. If the water is pooling on the ground, mark the area with a bucket, painter's tape, or chalk.
Check for Condensation
Eliminate condensation as the cause of the ceiling leak. If condensation is the source, add an exhaust fan or run a dehumidifier.
Look Upward From Pooled Water
Follow the pool of water upward. The drip area on the ceiling is usually obvious and remains even after the drip has dried up. Water travels downward, seeking the path of least resistance, though sometimes with a circuitous route.
Mark Water Leak Area
If the drip area on the ceiling is widespread, mark its outline with a pencil. Test areas that are not visibly obvious with the moisture detector.
The shape of the outline can help you determine where the leak is coming from above the ceiling. If the outline is circular, there's a good possibility that the leak is starting at the center point of that circle. If the leak is cone- or fan-shaped, the origin of the leak may be at the small part of the outline, with the water fanning outward from there.
Look for Collection Points
Light fixtures sometimes act as containers for ceiling leaks. The leak may not necessarily be directly above the fixture. Instead, the fixture is the lowest point on the ceiling, so it collects water. The tops of kitchen wall cabinets, too, act as collectors for water leaks.
If the area above the leak is an attic, access the attic by placing a ladder under the access door, usually located in a closet or a hallway. Bring a flashlight. Wear breathing protection and gloves. Locate the area of the leak. Roll up fiberglass insulation batts. For loose-fill cellulose insulation, scoop it up with a dustpan and set it aside.
Check Bottom of Roof
Visually follow a vertical sightline upward from the leak on top of the ceiling drywall. See if the underside of the roof is wet. Underside leaks of this type often start high and move downward. So, if the roof is leaking, the leak may be located at the beginning point of the leak's path.
Investigate Upper Floor
If the area above the ceiling leak is a habitable floor instead of an attic, try to locate the exact area above the ceiling leak by measuring inward to the leak from the walls. If a bathroom is directly above the leak—specifically the bathroom's toilet, shower, or bathtub—there is a good chance that the leak is coming from any of those. In some cases, water supply lines or drain lines behind walls or under floors may be leaking.
Examine Home for External Ceiling Leaks
Rest the extension ladder against the house to look at the gutters. Gutters full of leaves or debris can overflow back into the house’s attic. Gutters that do not maintain a slope of at least a 1/4-inch vertical drop per 10 horizontal feet can collect water and send it back into the attic.
From the top of the ladder, look at the roof. Raised, damaged, or missing shingles may be leak points. Damaged shingles near the edge of the roof may indicate water leakage from ice dams.
Examine Roof Ridge and Flashing
Walk on the roof and further examine the shingles, along with the roof ridge. Look at the metal step flashing alongside the chimney for signs of water entry points. Check all pipes and vents that extend from the roof.
Equipment / Tools
- Moisture detector
- Painter's tape or chalk
- Breathing protection
- Tape measure
- Tub drain removal tool
- Cordless drill
- Extension ladder
- Cordless drill
- Replacement pipes and fittings (as needed)
- Plumber's putty
- Teflon tape
- Toilet wax or silicone ring seal
- P-trap (as needed)
- Drywall, 5/8-inch
- Drywall screws
- Drywall joint compound
- Ice dam protection
- Gutters and related parts
- Gutter screens
- Roofing nails
How to Repair Internal Ceiling Leaks
Repair Toilet Leaking at Base
A ridge of water around the base of the toilet indicates that the toilet is leaking where it connects to the closet flange.
Fix Leaking Shower or Tub
Showers or bathtubs can leak water that spills over the side or from the faucet, drain, or overflow.
- Fix or replace shower doors that leak water over the side.
- Caulk between the bathroom floor and the bathtub or shower pan. If the floor is not moisture-proof, consider replacing it with sheet vinyl, tile, or luxury vinyl plank.
- Unscrew the showerhead and re-wrap the threads with Teflon tape. Replace the showerhead and tighten by hand.
- Unscrew the bathtub drain with a drain remover tool. Scrape away plumber’s putty and replace with fresh putty. Replace the drain and screw tightly into place.
- For bathtubs, use a screwdriver to unscrew the cover to the overflow drain. Make sure that the overflow drain meets the overflow hole on the tub and is properly sealed. Replace the cover.
Repair Leaking Water Lines or Drain Pipes
- Check the water supply line to the toilet and replace it if it is leaking.
- Under the bathroom sink, tighten or replace all water supply lines that are leaking.
- Also under the sink, run the water and make sure that the P-trap (drain) is not leaking. If so, re-install it or replace it.
- For leaking pipes behind walls, cut away the drywall with a jaw saw. Copper lines with pinhole leaks or faulty joints should be replaced by a licensed plumber. Or you can cut away the damaged line and replace it with PEX plastic pipe and push-fit connectors.
How to Repair External Ceiling Leaks
Fix Leaking Gutters
Replace Missing or Damaged Shingles
Remove the damaged shingles, then replace with new, matching shingles. If the wood roof deck below the shingles is damaged or rotted out, it will need to be replaced.
Add Ice Dam Protection
A long strip of ice dam membrane can be added along the edge of the roof to prevent thawed ice from leaking under shingles and into the attic. This is best installed prior to installing new shingles, not retroactively.
However, you can add electric heating cables that run in a zig-zag pattern to melt ice dams before they form. Electric heating cables are attached to the top of the shingles.
Replacing Leaking Flashing and Vents
For minor step flashing problems, you can replace the bent or missing areas with pre-formed sections of step flashing. For replacing all of the flashing, consult with a roofing company or mason.
How to Repair a Ceiling Damaged by Leaks
- Remove all water-logged ceiling drywall and insulation.
- Cut back the drywall (even undamaged drywall) to the nearest joists.
- Add two-by-fours along the joists to provide an attachment surface for the drywall screws.
- Cut a 5/8-inch-thick sheet of drywall to the size of the missing panel.
- With an assistant, lift the drywall into place.
- Screw the drywall onto the joists with a cordless drill and drywall screws. Space the screws every 7 to 8 inches along the edges and every 12 inches in the field (or center area).
When to Call a Professional
If you are having trouble locating the origin of the ceiling leak, call a licensed contractor. The contractor may help you locate the source of the leak at an hourly rate and may be able to help you make repairs. For all issues on the roof, including step flashing and vents, a roofing professional can provide assistance with tracing leaks and making all necessary repairs.
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"Important Facts About Falls." Centers For Disease Control.