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Home » A Comprehensive Guide to Repairing a Skylight Leak

A Comprehensive Guide to Repairing a Skylight Leak

    A skylight leak can occur for a variety of reasons. A leaking skylight can pose numerous issues for a homeowner, but it can also be a natural light source. A roof window, like a skylight, is a valuable addition to any home and gives an abundance of fresh air. The leaks in your roof window or skylight must be understood to be repaired; there are many simple options, such as DIY. If you own a commercial building, you may not be comfortable with a do-it-yourself solution; in that case, contact a roofing contractor with the necessary qualifications.

    Are There Any Skylight Leaks?

    There are two primary sources of leaks from a skylight or roof window, and we will look at both to help a building owner understand what they may be up against.

    Leaks in Cold Weather

    Condensation can cause a cold weather leak that does not leak at other times. When warm air with a moisture component collides with a hard surface, water drips into the room where the skylight or roof window is positioned. Monitoring the roof window or skylight during different weather patterns is one method for determining condensation. Clouds on the surface or the appearance of dampness during cooler temperatures – with no rainfall – should be enough to assess condensation. Other indicators of condensation include fog on inside windows, mold/mildew, and flaking paint. Cooking and drying clothes might cause condensation if there isn’t enough ventilation to remove the warm, damp air.

    Leaks in Heavy Rain

    When it rains, leaks become more visible. Condensation can be ruled out if your skylight leaks during rain showers. Structural damage – or old age – may be an issue; a fast skylight examination may be in order. Over time, flashing will rust, caulking may shrink or fracture, and seals will rot, allowing water to enter your home. Contact a roofing contractor if you need clarification on stepping on the Roof to inspect for any of the concerns listed below. Age is always a consideration when dealing with a roof window or skylight; if the flashing is the issue, replacing the entire skylight or roof window may be your only option. If you find a small gap at the flashing, use caulking or external silicone to seal it. Observe the skylight or roof window for the next several weeks to ensure the repair was successful.

    Leak Between the Glass and the Skylight Frame

    If you see a leak between the glass and the skylight frame, it is a skylight problem, not a roofing one. If your skylight has been in service for a while, the problem is caused by the weather seals drying up and shrinking. The waterproof seal is broken when this occurs, enabling water to enter. Caulk around the glass when repairing the problem. Make sure it’s a dry day – and you’ve had a few dry days in a row – because water between the glass will fog up.

    Leak Between the Skylight Frame and the Roof

    Check the ceiling around the skylight frame if your skylight leaks. You have a roof problem if it seems moist or feels wet. This is a flashing issue, as the flashing is deteriorating and enabling water to penetrate. Call a reputable roofer for an inspection to confirm the situation. After securing the flashing case, the roofer can replace the flashing. If the problem is faulty skylight installation, the roofer will need to rectify the deficiencies in the work and bring it up to code.

    Leaks Due to Flashing

    A skylight’s flashing is an essential component. It is the sleeve between the skylight and the roof cut-in. It gathers trash and acts as a watertight seal for the skylight insert. Clear the debris around the flashing so you can inspect it visually.

    How to Repair

    Age is always a consideration when dealing with a roof window or skylight; if the flashing is the issue, replacing the entire skylight or roof window may be your only option. If you find a small gap at the flashing, use caulking or external silicone to seal it. Observe the skylight or roof window for the next several weeks to ensure the repair was successful.

    Poorly Installed Roofs or Skylights

    Roof windows and skylights need better installation. After a rain, inspect newly installed roof windows or skylights to see if the building is competent. If you notice water flowing in shortly after installation, contact the contractor who installed it and requests that he return to make things right.

    Broken Closing Mechanism

    A quality control test should aid in determining the mechanical proficiency of the skylight. Close the skylight after opening it. When closed, the skylight should fit snugly against the frame, forming a tight seal. A leak will occur if the opening and shutting procedures are hampered.

    How to Repair

    If the closing difficulty is being hampered by debris, clear it out to ensure a good seal while closing the skylight. Take precautions to keep leaves and twigs from gathering around the skylight. You can’t always avoid branches and other impediments from blocking your skylight, but vigilance is your best bet for preventing stuff from accumulating at the skylight.

    Roof Leaks

    Roofs will always leak. The skylight leak could be the result of a leaking roof. Water enters the roofing system, rushes down to the skylight, and drips appear inside the home. Take action if you notice discoloration near the skylight or further up on the Roof. Another symptom of a problem is missing or broken roof shingles. It means that water has found an access point and that the skylight is not the source of the problem.

    How to Repair

    A leaking roof requires prompt treatment, or it will cause worse difficulties in the long run. You can get away with just repairing damaged or missing shingles. However, depending on the Roof’s age, you may need to restore/replace the complete Roof in the long term. You will know once a roofing contractor inspects the Roof and assesses the problem.

    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 the skylight or roof window is the source of the water between the sash and frame. If the leak is between the window and the reveal or between the reveal and the wall, it could suggest an installation issue. An underfelt collar lessens the likelihood of this happening. There is a difference between where water drips and where it appears. In many cases, the water you observe is there because water has found its way into your home through a hole or gap. As the Roof absorbs and transmits water to an entry point, the leak and drip points are located in two different locations.


    If your skylight was just installed, the leak you see indicates an installation issue.

    Flashing Installation

    The flashing kit with the skylight must be compatible with the installed product. Having the proper equipment eliminates gaps from forming, hence preventing leaks. In addition, for compatibility, the kit must be the correct type that connects to the roofing system.

    Underfelt Collar Installation

    Waterproofing is accomplished in two stages. First, if water gets in, adding an underfelt collar – a breathable membrane – should provide an extra layer of protection. Poor underfelt installation can cause leaks, which may be a condensation issue if the underfelt isn’t drying properly.

    Learn more: A Comprehensive Guide on Ice Dam Removal