How to Find and Fix Roof Leaks
You know the roof is bad when water stains the ceiling or walls. But unless shingles are missing or obviously damaged, finding the leak may be difficult because water can enter the roof in one place and run down to another before it starts soaking in. You may be able to spot the leak if you have an attic and go up there on a rainy day. Then you can mark the area and, on a nice day, have a helper tap on the mark while you’re on the roof. After you pinpoint the leak, apply roofing cement or new shingles as needed. Don’t forget to inspect the rubber seals called boots around the electric service and plumbing vent pipes, air vents, and exhaust fan flashing.
If you have a severe winter and your roof isn’t insulated well enough to keep the snow from melting, it doesn’t have to rain for the roof to leak. When a layer of snow on the roof melts, it first runs down and freezes over the eaves, which causes ice dams, and then the water backs up behind the dam and under the roofing shingles. Ultimately, water will seep in through the ceilings and walls.
Hardware and home improvement stores sell long-handled roof rakes. People have also been known to shovel the snow off the roof in the middle of winter — if you do that, be careful not to cut into the shingles (or fall off the roof!). A thick layer of insulation in the attic or crawl space provides an effective barrier, trapping warm air in the house where it belongs and keeping the roof itself cooler so the snow doesn’t melt quite as fast.
Many roof leaks occur around the chimneys and vents on roofs. Flashing is supposed to go under adjacent roof shingles and then up the chimney or pipe for a couple inches. The joints have to be sealed. If they aren’t, the water runs right down through the roof and into the house, although it may travel a little down the roof and actually enter at a lower point. If the sealant leaks or the flashing rips, you should reseal joints. You need a putty knife, a wire brush, roofing cement, and medium-weight sandpaper. Here’s what to do:
Using the putty knife and wire brush, take out the old sealant.
You get a better bond if it’s gone.
Brush out all debris.
Apply roofing cement along all joints.
Using the putty knife, push the cement into all of the joints, leaving a layer on the surface.
Scrape the putty knife on top of the cement to make it smooth.
If you have any holes, fill them with roofing cement.
If you see any ragged edges or areas that have the potential for going bad, smear roofing cement on top of them too.
If it’s the rubber boot around the pipe that’s cracked or broken, that can usually be replaced without replacing the whole flashing.