Look Uphill to Find Roof Leaks
Leaks are most commonly found along penetrations in the roofs’ surface, like
near skylights, vents, or other areas like valleys that experience heavy drainage,”
advises O’Brien. They might be several feet above the drip or to the right or left.
Go Into the Attic, if Possible
Leaks are easier to pinpoint if you have access to the attic. You might see water
spots or tracks on the underside of the roof decking, and some of the attic
insulation may be soaked. 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.
If you can’t see any telltale flow marks, look for ‘shiners’ poking through the
underside of the roof. A shiner is a nail that missed the framing member when
the roofer nailed down the roof decking. Moisture that escapes into the cold attic
from the rooms below often condenses on exposed nails, freezes on cold nights
and begins dripping when the attic warms up during the day. Shiners look white
at night because they’re frosted. The solution is to clip them flush to the decking.
Use this Trick to Find Difficult Leaks
If a leak is difficult to find, enlist a helper and go up on the roof with a garden
hose. Start low, soaking the area just above where the leak appears in the house,
and run the hose in isolated areas. For example, soak the downhill side of a
chimney first, then each side, then the top on both sides.
Let the hose run for several minutes in one area before moving it up the roof a
little farther. Have your helper stay inside the house waiting for the drip to appear
and ready to yell when it becomes visible, signaling that you’re in the
neighborhood of the leak. This process can take over an hour, so be patient,
don’t move the hose too soon, and be ready to buy your helper dinner.
If running water doesn’t reveal the exact location of the leak, don’t be timid. Start
removing shingles in the suspect area. You should see evidence of the leak when
they’re gone, such as discolored felt paper, water-stained or even rotted wood., references, or a list of completed projects.
Repair Damaged 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 might be rotted away or
torn, allowing water to work its way into the house along the pipe.
When you notice any of these problems, you should generally buy a new vent
boot to replace the old one. But if the boot is in good shape — other than the
fact that the nails at the base are missing or pulled free — you might not need a
new one. You can remove all the nails and replace them with the rubber-washer
screws used for metal roofing systems.
To replace the nails, you’ll have to work the adjacent shingles free on both sides.
Unless you have extra shingles, be careful when prying them up to avoid
damaging them. Use a flat bar to separate the sealant between the layers, then
drive the bar under the nail heads, pop out the nails and drive screws into the nail
holes.
Fix Leaky Roof Vents
Check for cracked housings on plastic roof vents and broken seams on metal
ones. You might be tempted to throw caulk at the problem, but that solution
won’t last long. There’s no better fix than replacing damaged vents. If the vent is
in good shape, look for pulled or missing nails at the base’s bottom edge and
replace them with rubber-washer screws.
If you have to replace a damaged vent, you can remove nails under the shingles
on both sides of the vent without removing the shingles. You’ll find nails across
the top of the vent, too, and you can usually work those loose without removing
shingles. After you’ve installed the new vent, squeeze out a bead of caulk
beneath the shingles on both sides to hold them down and add a water barrier.
That’s much easier than renailing the shingles.
Stop Leaks in Walls and Dormers
Water doesn’t always come in through the shingled surface. Wind-driven rain can
seep in from above the roof around windows, between corner boards and siding,
and through cracks and knotholes in siding.
Dormer walls provide plenty of opportunity for water to dribble down and seep
through the roof. Caulk between the corner boards, window edges, and siding
can be old, cracked or missing, allowing water to penetrate and work its way
behind the flashing and into the house. Even intact caulk may not fully seal
against the adjoining surfaces.
If you suspect leaky caulk, dig it out with a putty knife and replace it with a fresh
dose of high-quality caulk. While you’re at it, check the siding above the step
flashing at the base of the wall. Replace any cracked, rotted or missing siding,
ensuring the new piece overlaps the step flashing by at least two inches.
If you still have a leak, remove the corner boards and check the overlapping
flashing at the corner. Often, you’ll find old, hardened caulk that needs to be
replaced where the two pieces overlap at the inside corner.
Control Leaking at Roof Joints
Complex roofs need special attention, especially at joints where one roofline
meets another. The roof in this image leaks during the snowy part of winter and
during storms in the summer, no doubt because of poor flashing.
The soffit that meets the roof is one of the toughest areas to waterproof,
especially when the roof shows signs of an ice dam. O’Brien says that ice dams
“are most often caused by improper ventilation and insulation in your attic or by
clogged gutters, which allow ice to build up.” 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:
- Remove the shingles down to the roof decking.
- 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. - Slide metal step flashing behind the fascia board (the trim behind the
gutter) in such a way that the valley flashing laid over the joint where the
two roofs meet overlaps it by at least two inches. - Re-shingle.
Improved attic insulation and ventilation are usually the best ways to prevent ice
dams, but they might not be effective in this complicated leaky roof situation. If
not, consider installing heating cables on that part of the roof. Here are a few tips
on getting rid of the ice dams.ble for accidents or substandard work.
DIYers have also devised ways to deal with ice dams more safely with techniques
like roof deicing cables and ice dam pantyhose hack.timates can indicate subpar materials or a contractor cutting corners on labor.
Replace Damaged Step Flashing
Step flashing prevents leaks at the base of a wall that intersects the roofline. Each
short section of flashing channels water over the shingle downhill from it. If the
flashing rusts through, or a piece comes loose, water will run right behind it, and
go into the house.
Replace rusted flashing. To get the old flashing out, you have to remove any
shingles on top of it and pry the siding loose. Then you can fit new flashing under
the siding, affix it to the wall, replace the siding and then replace the shingles. It’s
that simple.
Don’t forget to nail it securely in place, or it will eventually slip down to expose
the wall. Check out this article for more on installing your own step flashing.
Patch Leaks Around Brick Chimneys
All kinds of bad things can happen around brick chimneys — far too many to
cover in this story. Galvanized steel flashing around chimneys can rust through,
especially at the 90-degree bend at the bottom, and water can seep into the
chimney and onto the roof, where it can rot the decking. You can do something
about that.
A quick but relatively long-term fix is simply to 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. Here are
complete instructions for installing chimney flashing the right way.
Fill 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, antenna mounting brackets or just about
anything. Don’t forget loose and exposed roofing nails. You need to pull these
and either replace them or patch the holes.
Small holes are simple to fix, but if you do it by injecting roofing caulk, the repair
may not last very long. Liquid flashing, which is intended for sealing recessed
windows, is a far better option. You can also make the repair by fitting metal
flashing under damaged shingles.
Don’t Over-Rely on Caulk!
Rarely will caulk or roof cement permanently cure a leaky roof on their own. You
should always attempt a “mechanical” roof fix whenever possible. That means
replacing or repairing existing flashing or shingles instead of using roof sealant as
a leak stopper. Only use caulk for very small holes and when flashing isn’t an
option as a leak stopper.
Clean Out the Gutters
This might seem like an unrelated chore, but according to O’Brien, clogged
gutters are a major cause of ice dams, and ice dams can cause leaks. When ice
backs up past the exterior wall, water can seep through the decking and into the
house when the ice melts. The results are stained drywall, mold and water
damaged framing.
This is another reason why gutter cleaning should be on your fall maintenance
to-do list.