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Complete Guide to Fixing a Skylight Leak

Complete Guide to Fixing a Skylight Leak

September 10, 2022

A skylight leak can happen for a number of reasons. A leaking skylight can cause many problems for a homeowner, but the skylight can be a source of natural light. A roof window is a beneficial addition to any home and like the skylight provides an abundance of fresh air to any home. The leaks your roof window or skylight is experiencing need to be understood to be corrected, there are many solutions that take a little effort – like DIY. If you operate a commercial structure, you may not be comfortable with a DIY solution, if that is the case call a roofing contractor with credentials to do the repair you need.

Are There Any Skylight Leaks?

There are two major causes for leaks for a skylight or roof window leak, and we will examine both to help inform a building owner about what they maybe up against.

Leaks in Cold Weather

A cold weather leak, that doesn’t leak at any other time can be attributed to condensation. When warm air that has a component of moisture meets a cold surface it creates water that drips in the room where the skylight or roof window is located. One way to make the condensation determination is to monitor the roof window or skylight during different weather patterns. Clouds on the surface or an appearance of wetness during cooler temperatures – with no rain fall – should be the indication you need to make a condensation determination. Other signs that will establish the condensation diagnosis are fog on interior windows, mould/mildew, and peeling paint. Cooking and drying clothes can contributed to condensation if you don’t have adequate ventilation to remove the warm, moist air.

Leaks in Heavy Rain

When rain falls, leaks come to the forefront. If your skylight leaks during rain showers, you can rule out condensation. At that point, structural damage may be a problem – or old age – in that case; a quick skylight inspection might be in order. Flashing will rust over time, caulking will shrink or crack, and seals will rot, letting water pass through into your home. Call a roofing contractor if you are uncomfortable getting on the roof to check for any of the problems mentioned here. Age is always a factor when dealing with a roof window or skylight, if you find the flashing is the problem, replacing the entire skylight or roof window might be your only choice. If you discover a small gap at the flashing, you can seal it with caulking or external silicone. Observe the skylight or roof window for the next couple of weeks to ensure that the repair you have enacted has succeeded.

Leak Between the Glass and the Skylight Frame

If you see a leak between the glass and the frame of the skylight, it isnt a roofing problem, it is a skylight problem. If your skylight has some years on it, the problem is created by the weather seals drying out and shrinking. Once that happens, the waterproof seal has been breached allowing water to enter. When fixing the problem, use caulking around the glass. Make sure that it is a dry day – and you have had a few consecutive dry days – otherwise any water between the glass will fog up.

Leak Between the Skylight Frame and the Roof

When your skylight leaks, check the ceiling around the skylight frame. If it appears damp or feels wet, you have a problem with the roof. This is a flashing problem, as degradation of the flashing is allowing water penetration. To confirm the problem, call a reputable roofer for an inspection. Upon confirmation of the flashing problem, the roofer can replace the flashing. If your problem is poor installation of the skylight, the roofer will need to address the inadequacies of the work and bring it up to standard.

Leaks Due to Flashing

Flashing is an integral element of a skylight. It is the sleeve between the skylight and the cut-in of the roof. It serves as a watertight seal for the skylight insert and collects debris over time. Clear the debris around the flashing for a visual inspection

How to Repair

Age is always a factor when dealing with a roof window or skylight, if you find the flashing is the problem, replacing the entire skylight or roof window might be your only choice. If you discover a small gap at the flashing, you can seal it with caulking or external silicone. Observe the skylight or roof window for the next couple of weeks to ensure that the repair you have enacted has succeeded.

Poorly Installed Roofs or Skylights

Poor installation is the bugaboo of roof windows and skylights. An inspection of recently installed roof windows or skylights after a rain will tell you if the installation has been competent. If you see water coming in just after installation, call the contractor who installed it to come back and make things right.

Broken Closing Mechanism

A quality control test should help determine the skylight’s mechanical proficiency. Open the skylight, then close it. When closed, the skylight should fit snug to the frame providing a leak-proof seal. If the opening and closing procedures are impaired, you will have a leak.

How to Repair

If you see that the closing problem is affected by some debris blockage, clear it out for a solid seal when closing the skylight. Also, take steps to prevent leaves and twigs from accumulating around the skylight. You can’t always stop branches and other impediments from blocking your skylight, but vigilance is the best option you have to prevent material from amassing at the skylight

Roof Leaks

Roofs leak, that is a given. The skylight leak might just be due to a leaky roof. Water entering the roofing system, runs down to the skylight and the drips start inside the home. You may have a problem if you see discolouration around the skylight or further up the roof, take action. Another sign of a problem is missing or damaged shingles on the roof. It means water has found an entry point and the skylight isn’t the problem.

How to Repair

A leaky roof needs attention immediately, lest it causes bigger problems in the long run. You may be able to get away with a minor repair – replacing damaged or missing shingles. But in the long run, depending on a roof’s age, you may need to restore/replace the entire roof. You won’t know for sure until a roofing contractor inspects the roof to get a handle on the situation.

Professional Skylight Roof Installer Recommendation

Here are a few tips for diagnosing the problem and creating effective solutions for your roofing/skylight problems.

Sourcing the Leak

Most roofing contractors will tell you that water between the sash and frame is due to the skylight or roof window. If the leak is between the window and reveal or the wall it could indicate an installation problem. An underfelt collar reduces the chances of that happening. Where water drips from and where it appears are two different things. In many instances, the water you see is there because the water has found a hole, or gap to enter your home. The leak and drip points are in two different places as the roof will absorb and transmit the water to an entry point.


The leak you see is an installation problem if your skylight has just been installed.

Flashing Installation

The flashing kit with the skylight must match the installed product. Having the correct kit prevents gaps from appearing, preventing leaks. Also, the kit must be the correct type that marries to the roofing system for compatibility.

Underfelt Collar Installation

Installation is a two-stage process for waterproofing. Adding an underfelt collar – a breathable membrane – should be an extra layer of protection should water find its way in. Poor underfelt installation can lead to leaks, and it might just be a condensation problem if the underfelt isn’t drying properly.

FAQs on Skylight Leak Repair

Are Leaking Skylights Covered by Homeowners Insurance?

General wear and tear is not covered. It will be covered if your skylight sustains damage from a weather event – a storm or falling tree.

How Much Does It Cost to Repair a Leaking Skylight?

It depends on the nature of the repair. If you have problems just after installation, the contractor may perform the repair free of charge as the leak has come from an installation problem.

Why is my Skylight Leaking After a New Roof?

There are many reasons for this situation. Poor installation causes gaps or holes that allow water in or the slope of the new roof is too low. High winds will force the shingles up and water gets in under the lifted shingles. Making contact with the roofing contractor and submitting a warranty claim could cut the costs to zero, depending on your arrangements in advance.

What to do When My Roof is Leaking?

Get the buckets out to catch the water that is getting in. Then call a reputable roofing contractor to come and assess the situation to effect the necessary repair.

How Integrity Roofers Can Help with Skylight Leaks

Skylight Installation, Replacement and Repair services in Toronto When you are having problems with your skylight, like leaks, there is only one roofing name you can trust: Integrity Roofers. Our staff has been providing effective solutions for skylight problems for decades. Our host of services runs the gamut of skylight repair. We can replace glass panels, replace worn-out gaskets and add new sealant. Also, when the flashing has failed, we can replace that too if your extrusions need to be addressed. We can re-glaze glass panels and transform them into high-performing or safety panels. To discuss your skylight situation, please reach out to us here. To obtain a free estimate, follow the link to our estimates page, and we will respond promptly.

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