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  • 14 December 2021

12 Roof Repair Tips: Find and Fix a Leaking Roof

You can stop leaks yourself-no experience necessary. We show you how to track down and fix the most common types of roof leaks. Most leaks take only minutes to repair.

Leaky Roof Overview

A leaky roof is likely to be the cause of stains on ceilings and down walls. The hard part of the roof leak repair is finding the leak; finding the leak is usually the easy part. In this article, we’ll show you how to fix most of the common types of leaky roofs using simple tricks. On the other hand, if you live in a Snow Belt and you have leaks only during warm or sunny days in the winter, you most likely have ice dams. We won’t go into that roof leak repair in this story.  Even if you don’t mind the leak much or if you’re getting a new roof next year, you should fix a leaky roof immediately. Leaks can lead to big problems over time, including mold, rotted framing and sheathing, destroyed insulation, and damaged ceilings. For over two years, stains on the ceiling indicated the flashing leak that caused an expensive repair bill. If the homeowner had dealt with it right away, the damage and subsequent repairs would have been minimal.

How to Find Roof Leaks

If you’re looking for leaks, look uphill from the stains. The first thing to look for is any roof penetrations. Leaks are most often caused by items that penetrate the roof. Even on older roofs, leaks are rare in areas of uninterrupted shingles. There are many types of penetrations in the roof, including plumbing, roof vents, chimneys, dormers, and much more. Several feet above or to the right or left of the leak, they can cause damage. A flashlight and a trip up into your attic with a flashlight can help you locate a leak if you have access to the attic. There will be water stains, black marks or mold. The suspect(s) can be examined on the roof if access is an issue or if you have a vaulted ceiling.

A Trick for Finding Difficult Leaks

Use a garden hose to locate a leak if you need a helping hand. Begin by soaking the area immediately above where the leak appears in the house. When you run the hose, isolate the affected areas. The downhill side of a chimney can be soaked first, followed by each side, and then the top on both sides. Tell your helper to stay inside the house while you wait for the drip to appear. After several minutes, move the hose up the roof a little further. Scream as soon as a drop appears on the roof. You are near the leak. Being patient and not moving the hose too soon is important during this process. Treat your helper to dinner. Don’t be timid if running water does not reveal the exact place where the leak is. Simply start removing the shingles. With them removed, there’ll be evidence of the leak and you’ll be able to track it down right to the source. You’ll see discolored felt paper or water-stained or even rotted wood directly below and around a leaky roof.

Solution for a Small Leak

Some roof leaks are tough to locate. Sometimes the water shows up at a ceiling spot distant from the leak. If your ceiling has a plastic vapor barrier between the drywall and the attic insulation, push the insulation aside and look for flow stains on the plastic. Often water runs to openings in the vapor barrier, such as at ceiling light fixtures.

The underside of the roof might have a shiner, which is a nail that missed the framing member, in this case when the carpenter nailed the roof sheathing to the rafters. If you don’t see any telltale flow marks, and since the stain is fairly small, look for flow marks on the underside of the roof. Moisture that escapes into the cold attic from the rooms below often condenses on cold nails. On a cold night, you can sometimes spot this if you climb up into your attic. Your nails will appear white because they are frozen. When the attic warms up a bit during the day, the frost melts and drips, then the nails frost up at night, and so on. Simple side-cutting pliers can be used to clip the nail.

Fix Plumbing Vent Boots

Plumbing vent boots can be all plastic, plastic and metal, or even two-piece metal units. Check plastic bases for cracks and metal bases for broken seams. Then examine the rubber boot surrounding the pipe. That can be rotted away or torn, allowing water to work its way into the house along the pipe. With any of these problems, you should buy a new vent boot to replace the old one. But if the nails at the base are missing or pulled free and the boot is in good shape, replace them with the rubber-washered screws used for metal roofing systems. You’ll find them at any home center with the rest of the screws. You’ll have to work neighboring shingles free on both sides. If you don’t have extra shingles, be careful when you remove shingles so they can be reused. Use a flat bar to separate the sealant between the layers. Then you’ll be able to drive the flat bar under the nail heads to pop out the nails.

How to Fix Roof Vents

Plastic roof vents may have cracked housings, and metal roof vents may have broken seams. While you might be tempted to throw caulk at the problem, that solution will not last very long. If the damaged vents cannot be repaired, they need to be replaced. Inspect the base for missing or pulled nails. Replace them with rubber-washered screws. In most cases, you Under most circumstances, you can remove nails under the shingles on both sides of the vent to pull it out. There will be nail holes along the top of the vent as well. These can usually be worked loose without removing the shingles. Use rubber-washered screws to secure the bottom. On both sides of the vent, apply a bead of caulk beneath the shingles to prevent water from leaking through. Renailing the shingles is more difficult.

Fix Walls and Dormers

The shingle surface is not always a point of entry for water. Wind-driven rain often enters from above the roof, particularly around windows, between corner boards and siding, and through cracks and knotholes in siding. The walls of dormer windows provide plenty of places where water can leak down and enter the roof. Old, cracked, or even missing caulk can be found between corner boards and between window edges and siding. These cracks allow water to penetrate and enter the house behind the flashing. It is possible for caulk that appears intact to fail to seal against adjacent surfaces. Make sure the area is sealed with a putty knife. Caulk that is suspect should be removed and replaced with high-quality caulk. Inspect the siding above the step flashing as well. The new siding should overlap the step flashing by at least two inches if it is cracked, rotted or missing. If you still have a leak, pull the corner boards free and check the overlapping flashing at the corner. Often, there’s old, hardened caulk where the two pieces overlap at the inside corner.

Complex Roof Problem

This roof leaks during the snowy part of winter and during storms in the summer, certainly due to poor flashing. The soffit that meets the roof is one of the toughest areas to waterproof. In the photo, you can still see signs of an ice dam. An ice dam occurs when snow melts and the water freezes when it hits the colder edges of your roof. Eventually, water pools behind the dam and works its way back up under the shingles and under the soffit until it finds an opening through the roof. The solution begins with good flashing since this should stop leaks from rainfall and might stop the leaks from ice dams as well. Begin by removing the shingles down to the wood sheathing and slip a strip of adhesive ice-and-water barrier (available where roofing repair products are sold) under the soffit/main roof joint. Depending on how the roofs join, you may have to cut a slot to work it in far enough. It should overlap another piece of ice-and-water barrier laid below, all the way down to the roof edge. This should cover the most leak-prone areas. Then reshingle, sliding metal step flashing behind the fascia board (the trim behind the gutter). The valley flashing, laid over the joint where the two roofs meet, should overlap the step flashing at least 2 in. If leaks continue to occur from ice dams, consider installing roof edge heating cables. (Find them locally at hardware stores or home centers.) Improved attic insulation and ventilation are usually the best ways to prevent ice dams, but they might not be effective in this complicated

Fix Step Flashing

Step flashing is used along walls that intersect the roof. Each short section of flashing channels water over the shingle downhill from it. But if the flashing rusts through, or a piece comes loose, water will run right behind it, and into the house it goes. Rusted flashing needs to be replaced. That means removing shingles, prying siding loose, and then removing and replacing the step flashing. It’s that simple.

Don’t Count on Caulk!

Rarely will caulk or roof cement cures a leaky roof —at least for very long. You should always attempt a “mechanical” leaky roof fix whenever possible. That means replacing or repairing existing flashing instead of using any type of sealant as a leak stopper. Only use caulk for very small holes and when flashing isn’t an option as a leak stopper.

Fix Small Holes

Tiny holes in shingles are sneaky because they can cause rot, a leaky roof and other damage for years before you notice the obvious signs of a leak. You might find holes left over from a satellite dish or antenna mounting brackets or just about anything. And exposed, misplaced roofing repair nails should be pulled and the holes patched. Small holes are simple to fix, but the fix isn’t to inject caulk in the hole. You’ll fix this leaky roof problem with flashing.

Leaks Around Brick Chimneys

All kinds of bad things can happen around brick chimneys. In fact, there are far too many to cover in this story. Flashing around chimneys can rust through if it’s galvanized steel, especially at the 90-degree bend at the bottom. A quick but fairly long-term fix is to simply slip new flashing under the old rusted stuff. That way any water that seeps through will be diverted. The best fix, though, is to cut a saw kerf into the mortar and install new flashing.