How to Fix a Leaking Skylight | Causes & Repair Tips
A leaking skylight can quickly turn a beautiful source of natural light into a frustrating and potentially damaging problem for your home. Water stains on ceilings, dripping sounds during rain, or visible moisture around the skylight's frame are clear indicators that something is amiss. Prompt action is crucial to prevent further damage to your interior and roofing structure. Masterpiece Roofing is here to guide you through the common causes of skylight leaks, how to detect them, and when it's time to call in the professionals.
Common reasons skylights leak
Understanding why your skylight is leaking is the first step toward finding a lasting solution. While many homeowners assume a cracked pane of glass is the culprit, the issue is often more complex. Here are the most common reasons skylights leak:
Improper Installation: This is a leading cause, especially for newer skylights. If the skylight wasn't properly flashed, sealed, or integrated with the roofing material during installation, gaps or weak points can allow water to seep in, often becoming apparent years later.
Damaged or Deteriorated Flashing: Flashing refers to the metal or vinyl strips installed around the skylight's perimeter to divert water away. Over time, flashing can rust, crack, lift, or become separated due to weather exposure, age, or improper installation. When flashing fails, water can bypass the protective layers and enter your home.
Worn or Damaged Seals/Gaskets: The seals around the glass pane, between the glass and the frame, or where the frame meets the roof opening can degrade over time due to UV exposure, temperature fluctuations, and general wear. Cracks, hardening, or shrinking of these seals compromise the watertight barrier.
Cracked or Damaged Skylight Lens (Glass/Acrylic): While less common than flashing or seal issues, the skylight lens itself can crack due to impact (e.g., hail, falling debris) or thermal stress. Even a hairline crack can allow water to penetrate.
Condensation Misdiagnosed as a Leak: In some cases, what appears to be a leak is actually condensation. When warm, moist indoor air comes into contact with the cooler surface of the skylight glass (especially in humid environments or during cold weather), condensation can form and drip, mimicking a leak. Poor ventilation in the room or attic can exacerbate this.
Clogged or Improper Drainage: Skylights often have small weep holes or drainage channels designed to carry away condensation or minor amounts of water that get past the initial seals. If these are clogged with debris (leaves, dirt) or were improperly designed, water can back up and eventually overflow into your home.
Roofing Issues Around the Skylight: Sometimes, the leak isn't directly from the skylight but from compromised roofing materials nearby, such as missing, damaged, or poorly sealed shingles, tiles, or membrane sections immediately adjacent to the skylight. Water can then travel under these materials and enter around the skylight opening.
Step-by-step leak detection
Finding the exact source of a skylight leak can be challenging, as water often travels along structural elements before dripping, making the drip point appear far from the actual entry point. Here’s a systematic approach to leak detection:
Initial Interior Inspection:
Look for water stains, discoloration, peeling paint, or dampness on the ceiling, walls, and interior frame directly below or around the skylight. Note the exact location and extent of the damage.
Place buckets or towels to catch any active drips to prevent further interior damage.
Exterior Visual Inspection (Safety First!):
Always prioritize safety. If you are not comfortable or equipped to get on your roof safely, do not attempt this step yourself. Call a professional roofer.
From a safe vantage point (e.g., a sturdy ladder), visually inspect the skylight and the surrounding roof.
Look for:
Damaged or lifted flashing: Are any metal pieces bent, cracked, rusted, or detached?
Compromised seals/gaskets: Are the seals around the glass or frame cracked, brittle, or pulling away?
Cracks in the glass/lens: Even hairline cracks can be a source.
Debris: Are there leaves, twigs, or other debris accumulated around the skylight, potentially blocking drainage?
Damaged roofing materials: Check shingles, tiles, or membrane directly uphill and to the sides of the skylight for cracks, missing pieces, or signs of wear.
Clogged weep holes: Look for small drainage holes at the bottom of the skylight frame; ensure they are clear.
Water Test (If Safe & Necessary):
This step is best done with two people: one on the roof with a garden hose, and one inside the attic/room monitoring for leaks.
Start low: Begin by wetting the roof area below the skylight. Gradually work your way up, soaking different sections around the skylight for several minutes each (bottom, sides, then top).
Isolate the source: The person inside should yell when water appears. This helps pinpoint the area where the leak is originating.
Distinguish from condensation: If the leak only occurs during or immediately after rain (and not just during cold, humid weather), it's likely a true leak, not condensation.
Attic Inspection (if accessible):
With a flashlight, look for water stains, mold, or damp insulation on the underside of the roof deck and rafters near the skylight. This can help trace the path of the water.
DIY skylight leak repairs
For very minor, easily identifiable issues, some homeowners might attempt DIY repairs. However, it's crucial to understand the limitations and risks. These are typically temporary fixes, and professional intervention is often needed for a lasting solution.
Clean and Clear Debris: Often, simply removing accumulated leaves, pine needles, and dirt from around the skylight and clearing clogged weep holes can solve minor drainage-related "leaks." Use a soft brush or cloth and gentle cleaner.
Re-apply Exterior Sealant (Temporary):
If you find small cracks or gaps in the sealant around the exterior frame or flashing (where the skylight meets the roof), you can try carefully removing old, deteriorated caulk with a putty knife and then applying a new bead of high-quality, exterior-grade, UV-resistant, flexible sealant (like silicone or a specialized roofing sealant compatible with your skylight and roofing material).
Ensure the surface is completely clean and dry before applying. This is a temporary measure and often indicates a deeper flashing or installation issue.
Interior Condensation Management: If the issue is determined to be condensation:
Improve ventilation in the room (e.g., use exhaust fans, open windows).
Consider a dehumidifier.
Ensure proper insulation around the skylight shaft in the attic to minimize temperature differences between interior and exterior surfaces.
DIY Cautions:
Safety: Working on a roof is dangerous. Falls can cause severe injury or death. If you're uncomfortable with heights or roof work, do not attempt DIY.
Wrong Fixes: Applying sealant over moisture or damaged flashing will not solve the underlying problem and can trap water, leading to more extensive damage later.
Voiding Warranties: Improper DIY repairs can void both your skylight and roofing warranties.
When to call a roofing professional
While minor issues might be temporarily addressed by a savvy DIYer, there are many situations where calling Masterpiece Roofing or another experienced professional is not just recommended, but essential:
Persistent Leaks After DIY Attempts: If your DIY efforts don't stop the leak, or if the leak returns quickly, it's a clear sign of a more complex problem that requires professional expertise.
Damaged or Improper Flashing: Repairing or replacing flashing correctly is a highly skilled job that requires specific tools, materials, and knowledge of roofing techniques for various materials (shingles, metal, tile). Incorrect flashing is the primary cause of leaks.
Structural Damage: If you notice soft spots on your roof deck, visible wood rot, or signs of compromised structural integrity around the skylight, immediate professional intervention is necessary.
Cracked Skylight Lens: A cracked glass or acrylic lens typically requires replacement of the entire skylight unit, which is a job for a professional.
Leaks from a Recently Installed Skylight: If a skylight leaks shortly after installation, contact the original installer immediately. This is almost certainly an installation error that should be covered under their warranty.
Age of the Skylight: Most skylights have a lifespan of 20-30 years (similar to many roofing systems). If your skylight is old and leaking, replacement is often more cost-effective than continuous repairs. A professional can advise on this.
Uncertain Leak Source: If you cannot confidently pinpoint the source of the leak, a professional roofer has the diagnostic tools and experience to find it accurately.
Safety Concerns: If accessing your roof is difficult, steep, or dangerous, always defer to a professional. They have the training, safety equipment, and insurance to work safely.
Preventative maintenance tips
Proactive maintenance can significantly extend your skylight's life and prevent costly leaks.
Regular Cleaning: At least twice a year (spring and fall), clean the exterior of your skylight, removing leaves, twigs, dirt, and any other debris. Use a mild soap and water solution with a soft brush or cloth. Ensure weep holes are clear.
Clear Gutters and Drainage: Keep surrounding gutters and roof drainage systems clear of debris to ensure water flows off the roof efficiently and doesn't pool around the skylight.
Inspect Seals and Flashing Annually: Visually inspect the seals around the glass and frame, as well as all exterior flashing, for any signs of cracking, lifting, or deterioration. Address minor issues promptly.
Trim Overhanging Branches: Cut back any tree branches that hang over your skylight to reduce debris accumulation and the risk of impact damage during storms.
Monitor for Condensation: If your skylight is prone to condensation, ensure adequate ventilation in the room and consider improving attic insulation around the skylight shaft to regulate temperatures.
Professional Inspections: Schedule regular professional roof inspections (ideally annually or bi-annually). Masterpiece Roofing can identify potential weaknesses or early signs of wear on your skylight and the surrounding roof before they turn into major leaks.
Don't let a leaking skylight compromise your home's integrity. For reliable diagnosis and expert repair, contact Masterpiece Roofing today!
