You’re standing under the overhang after a heavy London downpour, and there it is again, that steady drip landing right at the corner of your eavestrough, splashing onto the flower bed or, worse, running down your foundation wall. Maybe you’ve already grabbed a ladder and dabbed some caulking on it. Maybe it worked for a month. Then the next storm rolled through off Lake Huron, and the leak came right back.
If this sounds familiar, you’re not alone. Corner and seam leaks are, by far, the most common eavestrough complaint we hear from homeowners across London. The good news is that this isn’t a mystery; there are specific, well-understood reasons why eavestroughs fail at these exact points, and most of them are entirely preventable with the right repair or installation approach.
Why Corners and Seams Are the Weakest Point in Any Eavestrough System
Eavestroughs are built to move water in one direction: along a gentle slope toward a downspout. Every straight run of trough is relatively simple; it is one continuous piece with fewer places for water to escape. Corners and seams are different. These are the points where two sections of trough meet, angles change direction, and contractors join materials using sealant, fasteners, or mitred cuts.
Any place where two pieces meet is more vulnerable to separation, shrinking, or shifting over time. That is simply physics. As a result, corners and seams are often the first areas to require eavestrough repair. When dealing with leaking eavestroughs, the real problem is commonly found at these connection points, even when the water appears to be dripping from somewhere else along the run. Timely eavestrough repair can help reseal weakened joints, prevent further water damage, and restore proper drainage.
What Causes Eavestroughs to Leak at Joints
Homeowners often ask us what causes eavestroughs to leak at joints, expecting one simple answer. In reality, it’s usually a combination of a few factors working together over time.
Sealant Breakdown
Every corner joint and seam relies on a bead of sealant to keep it watertight. That sealant is exposed to London’s full seasonal swing: humid summers, freeze-thaw cycles in winter, and year-round UV exposure. Over five to ten years, even quality sealant dries out, cracks, and pulls away from the metal. Once that happens, you’ve got an eavestrough corner leak waiting for the next rainfall.
Thermal Expansion and Contraction
Aluminum eavestroughs expand in the summer heat and contract in the cold. That constant movement puts stress directly on the joints, since the straight sections shift slightly while the corner pieces try to hold everything together. Over enough cycles, tiny gaps open up at the seams — often invisible until it rains.
Improperly Installed or Mismatched Corners
Not all eavestrough corners are created equal. Pre-formed corner pieces need to be fitted, fastened, and sealed correctly the first time correctly. When a corner is rushed, undersized, or paired with the wrong sealant for the material, it’s only a matter of time before water seeps in.
Debris Buildup and Standing Water
Leaves, shingle grit, and seed pods collect at corners more than anywhere else on the system, since that’s where water naturally slows down. When debris blocks the flow, water backs up, sits under pressure against the seam, and works its way through any weak point, even a joint that was fine the year before.
Sagging or Improperly Pitched Sections
If your eavestrough has lost its slope, water won’t reach the downspout efficiently. Instead, it pools near the nearest low point, which is frequently a corner. Standing water is far more likely to force its way through a seam than water that’s moving steadily along.
Eavestrough Leaking at Corners After Rain: What It’s Really Telling You
Noticing your eavestrough leaking at the corners after rain, while remaining dry the rest of the time, is a useful diagnostic clue. It suggests that the leak is related to water volume and flow rate rather than a random hole in the metal. This usually points to one of three issues: a failed sealant joint, a clog forcing water to back up, or a corner that is undersized for the amount of roof runoff it must handle.
London homes with steep rooflines or multiple valleys directing water into one corner are especially vulnerable because that joint is handling more water than a standard connection may be designed to manage. Experienced eavestrough installers can assess the slope, drainage capacity, corner joints, and downspout placement to determine whether the issue requires resealing, cleaning, reinforcement, or a system upgrade.
How London’s Weather Makes the Problem Worse
London homeowners face a unique combination of conditions that accelerate eavestrough wear more quickly than in milder climates. Heavy spring rain, humid summer storms, and harsh winter freeze-thaw cycles all put extra stress on aluminum systems and their joints. Ice damming along rooflines in January and February is especially tough on corners, as expanding ice can physically pry a seam apart.
These seasonal conditions are also a common reason homeowners need professional gutter leak repair, particularly when repeated expansion and contraction weaken older joints. If your eavestroughs were installed more than eight to ten years ago, seasonal stress like this is very likely contributing to the problem you are seeing now.
How to Fix Leaking Eavestrough Seams
Leaking eavestrough seams can start as a small drip but quickly lead to water damage if left unrepaired.
A DIY fix, cleaning the joint, drying it thoroughly, and applying a fresh bead of exterior-grade sealant, can buy you some time if the leak is minor and recently developed. But it’s genuinely a short-term measure. Without addressing the underlying cause (movement, poor original installation, or a section that’s lost its pitch), the same joint tends to fail again within a season or two.
A proper eavestrough leak repair typically involves removing the compromised section, re-fastening or replacing the corner piece, correcting the slope if needed, and resealing with a commercial-grade product rated for the material and climate. In cases where the eavestrough is older, or multiple joints are failing at once, a full or partial replacement is often more cost-effective than repeated patch jobs.
Signs It’s Time to Call for Eavestrough Repair
- Water stains or streaking on the siding directly below a corner
- Visible daylight through a seam when viewed from underneath
- Pooling water in your flower beds or along the foundation after rain
- Sagging sections near a corner joint
- A corner that was already patched once and has started dripping again
If you’re noticing any of these, it’s worth having a professional look before the next major storm rather than after.
Why London Homeowners Trust AM Group Exteriors
We understand that letting a contractor onto your roofline is a decision built on trust, not just price. AM Group Exteriors has been part of Ontario’s home exteriors industry since 1956, and we’re proud to remain a family-run business today, serving homeowners across London and Southwestern Ontario.
A few reasons local homeowners choose us for eavestrough work:
- 24/7 Emergency Response: Fast emergency repair solutions help minimize downtime, reduce disruption, and protect the property from further damage.
- Local, accountable service. With a showroom presence across Southwestern Ontario, we’re not a fly-by-night crew passing through London after a storm; we’re here for the long term.
- Straightforward assessments. Our team inspects the actual cause of your leak, not just the symptom, so you’re not paying to patch the same joint twice.
Ready to Stop the Dripping for Good?
A corner leak rarely fixes itself, and each rainfall it’s ignored adds a bit more risk to your fascia, siding, and foundation. If you’re dealing with a persistent eavestrough corner leak or you’ve noticed dripping after every storm, the smartest next step is a proper on-site assessment, not another tube of caulking.
AM Group Exteriors’ experienced eavestrough installers offer free, no-pressure consultations for London homeowners, so you can find out exactly what’s causing the leak and what it will take to fix it right the first time. Request your free quote online to get it sorted before the next rain rolls in.e.
FAQs
Corners and seams are joined sections, which makes them naturally more vulnerable to sealant failure and movement than a single continuous run of trough. Straight sections rarely leak unless the metal itself is physically damaged.
You can, and it may temporarily slow the leak, but it usually isn’t a lasting fix if the underlying cause is a pitch issue, an aging joint, or repeated freeze-thaw stress. A professional repair addresses the root cause, not just the symptom.
We recommend at least once a year, ideally in the fall before leaves and debris build up, and again after any major storm or ice event during the winter.
If it’s one isolated joint on an otherwise sound system, a repair usually makes sense. If multiple corners are failing or the eavestroughs are older, replacement is often the more cost-effective long-term choice.
Yes. Water escaping at a corner tends to run straight down siding and foundation walls, which, over time, can contribute to staining, rot, and even basement moisture issues.
Yes, AM Group Exteriors provides free, no-obligation consultations and quotes for eavestrough repair and installation throughout London and the surrounding area.
