A water stain on the ceiling is rarely directly under the hole in the roof. Water runs along rafters, sheathing and pipes before it drips. Finding the source is most of the work; the repair itself is often small.
Working on a roof is dangerous. Falls from ladders and roofs are a leading cause of serious injury, and OSHA’s ladder safety guidance applies to homeowners too. Never go on a wet, icy or steep roof, and hire a roofer if you are not comfortable at height.
Find the leak from the inside
On a dry day, go into the attic with a flashlight. Look for water stains, dark wood, wet insulation or mold, and follow the trail uphill. Common sources:
- Flashing around chimneys, skylights and walls
- Rubber boots around plumbing vent pipes, which crack with age
- Missing, cracked or curled shingles
- Valleys, where two roof planes meet
- Ice dams in cold climates, which push meltwater under shingles
If you cannot find it, have someone in the attic while another person runs a garden hose over one section of roof at a time, starting low and moving up.
Temporary repair
If it is raining, put a bucket under the drip and poke a small hole in a bulging ceiling to let water out in a controlled way. From outside, a tarp secured over the ridge with boards (not nails through the tarp into the roof surface) can protect the area until a proper repair.
Common repairs
- Damaged shingle: lift the shingle above, remove the nails, slide in a new shingle, nail it and seal the nail heads with roofing cement.
- Cracked vent boot: replace the rubber boot, or slip a repair collar over it.
- Loose flashing: reseal with roofing sealant suitable for the material, or replace sections of flashing. Chimney flashing usually has step and counter flashing that a roofer should redo if it is badly damaged.
Roof sealants are a short-term solution on their own; they crack after a few seasons in the sun.
Dry out the inside
Replace wet insulation, let the area dry and check for mold before repainting the ceiling with a stain-blocking primer.
When to call a roofer
Leaks in several places, sagging areas, a roof near the end of its life (often 20 to 30 years for asphalt shingles), or any steep roof are jobs for a professional. If it is time for a new roof, compare options in the different types of roofing materials. Moisture problems inside are covered in how to prevent mold and mildew.
