Skylight Leaks: How to Diagnose and Repair

What skylight leak repair means and why it matters

Skylight leaks are rarely about the glass itself. Water almost always finds a path around the frame, under the shingles, or through tired flashing. Roof repair for skylights focuses on restoring the waterproofing system that surrounds the unit, from the shingles and underlayment to the flashing, curb, and sealants. Left unattended, a small drip can turn into swollen drywall, mold, and damaged insulation, and in cold regions, leaks compound ice dam problems. Whether your home has asphalt shingles, metal roofing, or a low-slope section with TPO or EPDM, the principles are the same: control water, channel it away from the opening, and keep the roof assembly ventilated so it can dry between storms.

Compared with full roof replacement, skylight repair is a surgical approach. It is targeted, usually faster, and far less expensive than new roof installation. Still, it requires careful roof inspection services to identify the true entry point. In my experience, the visible drip often appears several feet away from where water actually gets in. Understanding that disconnect is the starting point for an effective fix and long-term roof maintenance.

How do you know your skylight needs repair?

Start inside. Water stains at the skylight corners, bubbling paint on the shaft, or a fogged double-pane that never clears all signal trouble. On windy nights, you might hear a soft whistle if gaskets have shrunk. In winter, watch for condensation on the interior frame. Some moisture from indoor humidity is normal, but steady weeping usually indicates inadequate ventilation or a failed thermal break, and that excess moisture can mimic a leak.

Outside, look for cracked shingles around the skylight, granule loss that exposes asphalt, or flashing that looks lifted or dented from hail damage. On metal roofing, examine the panel seams and butyl tape near the curb. For flat roofing materials such as TPO, EPDM, or PVC, focus on the welded seams at the curb flashing and any punctures. The most common culprits I find: step flashing that was never interwoven correctly with shingles, a missing head flashing at the uphill side, or a clogged cricket that traps debris. If you see moss and algae growth creeping up to the skylight, that area stays wet too long and invites trouble.

If you have a vented skylight, check the operable hardware. Gaps at the sash, brittle gaskets, or loose hinges let wind-driven rain past the usual defenses. Finally, inspect gutters and valleys above the skylight. Poor drainage sends more water to the opening than it was designed to handle, which can lead to leaks even when the skylight itself is sound.

The real cost of skylight roof repair

Roof repair cost for skylight work varies widely because the scope ranges from resealing a minor gap to reframing and replacing a curb. For a simple shingle-skirt reseal, expect a few hundred dollars in roofing labor cost. Reflashing a skylight with new step, apron, and head flashing often lands between 600 and 1,500 dollars in many markets, depending on roof pitch, height, and access. If the roof deck shows rot, add sheathing replacement. A new factory flashing kit and compatible underlayment add materials cost, and if the skylight itself has failed, full replacement brings the total to several thousand, roofing services especially for larger units or solar-powered vents.

If your roof is near the end of its lifespan, an isolated repair may not be the best value. The roof replacement cost to add new flashing during a tear-off is typically lower per unit than standalone repairs because crews already have shingles removed. Measured another way, the average roof cost per square foot on a full reroof spreads labor and staging across the whole project. Sometimes replacing a tired skylight during new roof installation is the cheaper long-term move, especially if you have curling or buckling shingles nearby or widespread granule loss.

Emergency roof repair can nudge the price up due to off-hours dispatch and temporary tarping. Insurance may help for storm damage roof repair from hail or wind damage to the roof, but not for aging sealants or long-term neglect. Always read your roof warranty coverage, and check whether the skylight carries its own manufacturer warranty, which often requires specific flashing kits and roof maintenance to stay valid.

Walkthrough: diagnosing a skylight leak like a pro

A careful diagnosis saves money. Begin on a dry day with good light. From the attic, trace stains uphill along rafters to find the highest visible water mark. That is usually closest to the entry point. Note whether the stain appears around the skylight curb, along the sides, or above it. Next, inspect the roof surface. On shingle roofs, gently lift shingles to confirm step flashing is present with each course. There should be a head flashing on the uphill side and an apron flashing at the bottom. Look for nails too close to the skylight or through flashing. On low-slope roofs, probe seams with a blunt tool to spot failed welds. Any punctures and penetrations near the curb are suspects.

If the source remains elusive, perform a controlled water test. Start low at the sill, wet for several minutes, then move to the sides, then the head flashing, then several feet uphill. Pause between steps and watch inside. This method isolates the entry zone. Avoid blasting water against the glass where it can bypass gaskets in an unrealistic way. If the leak only appears with melting snow, you may have ice dams. Warm roof air, inadequate ventilation, and heat loss melt snow, and the refreeze at the eaves drives water sideways into weak points, including skylight flashing. In that case, the skylight repair succeeds only if you address insulation, air sealing, and attic ventilation along with the flashing.

DIY skylight repair, or call a pro?

Homeowners with solid ladder skills and comfort on a roof can handle minor resealing, cleaning debris from a cricket, or swapping a worn gasket. Beyond that, know the risks. Improperly interwoven step flashing can trap water and force it under shingles. Caulk is not a cure-all. Slathering sealant on failed flashing often makes a future roof replacement harder and costlier. On low-slope membranes, the wrong primer or incompatible sealant can void warranties, and repairs may peel under UV exposure. Safety matters too. A slick roof near a skylight is treacherous, especially on metal roofing or steep pitches.

When the leak stems from structural issues, roof aging, or flashing damage, hire an experienced residential roofing or commercial roofing contractor who works with your specific material. Ask for photos before and after, and ensure they use the skylight manufacturer’s flashing kit. If the rooftop shows broader problems like missing or damaged shingles, cracked shingles, or inadequate ventilation, a focused skylight fix may not last. A good contractor will explain the trade-offs and where a repair ends and a partial or full roof replacement begins.

Step-by-step for a proper skylight reflashing

On an asphalt shingle roof, a thorough reflashing usually includes removing shingles around the skylight, inspecting the curb, replacing damaged sheathing, installing an ice and water membrane that wraps up the curb, then reinstalling step flashing with each shingle course, finishing with a head flashing and apron flashing. Nails go high and away from the cut lines, and flashing overlaps follow water flow. On metal roofing, a new curb with pre-bent flashing panels and high-temp underlayment is the durable route. For TPO, EPDM, or PVC, weld a new curb wrap, then install a compatible metal counterflashing if required. In all cases, avoid relying solely on surface caulks. Use sealants as gaskets between rigid parts, not as exterior bandaids.

Ventilated shaft finishes also matter. If condensation was part of the problem, add air sealing at the shaft, continuous insulation, and proper vapor control. These details cut winter drips that look like leaks and help extend the roof lifespan.

Preventing skylight leaks before they start

Prevention is more than an occasional dab of sealant. Schedule roof inspection services every one to two years, or after severe storms. Keep gutters clear so water does not overwhelm the head flashing. Trim branches to prevent tree damage to the roof and to reduce debris build-up on crickets. In snowy climates, address ice dams with air sealing at the attic floor, balanced intake and exhaust ventilation, and, if needed, heat cables as a last resort. For aging skylights, budget to replace units during your next reroof. The incremental cost is small compared with labor to remove and reinstall around an old unit later.

If sustainability is on your mind, there are eco-friendly roofing choices to pair with skylights. High-reflectance shingles, green roofs in appropriate structures, or solar shingles all change heat dynamics around openings. Plan details accordingly. On multi-family roofing or industrial roofing solutions, standardized flashing details across units reduce maintenance time and improve quality control.

What if the skylight itself failed?

Skylights can fail at seals or glazing. A permanently fogged unit often means the insulated glass seal has broken, allowing moisture between panes. That is not a roof leak in the traditional sense, but it is a comfort and efficiency issue. Replacement glass or a new unit may make more sense than trying to reseal. Operable skylights have wear parts. If the crank or motor fails to close the sash tight, wind-driven rain will find its way in. Some modern units come with rain sensors and improved gaskets, which, combined with better roof sealing and coatings, reduce maintenance. When replacing, consider the roof installation cost impact in the context of an upcoming reroof. Coordinating work minimizes flashing seams and saves labor.

Choosing a contractor without getting burned

Look for proof of skylight-specific experience, not just general roofing. Ask to see a recent skylight reflashing job on the same roof type you have, whether that is asphalt shingles, slate roofing, cedar shake roofing, tile roofing, or a flat membrane. A credible roofer welcomes the questions and explains their sequence of work. Verify insurance and licensing, and compare bids carefully. If one bid is far lower, study the scope. Does it include ice and water underlayment up the curb, or only a surface sealant? Are they replacing damaged sheathing? Will they rebuild a proper cricket on the uphill side if the skylight is wider than the rafter spacing?

For local validation, compare third-party profiles and reviews. You can see customer feedback for a Minnesota roofing company or check a BBB profile for a contractor to learn how they handle warranty callbacks. If you need a quick way to find pros in your area, click to learn more through this curated directory of roofing specialists. These references help separate disciplined crews from caulk-and-go operations.

When repair gives way to replacement

Skylight leaks sometimes reveal broader roof issues. If you see a sagging roof, widespread cracked shingles, or multiple areas of flashing damage, a series of spot repairs is false economy. At that point, discuss roof financing options and the roof replacement cost for addressing the entire system. Replacing a roof lets you upgrade underlayments, correct inadequate ventilation, and reset every penetration properly. This is the moment to compare asphalt shingles vs metal roofing, and to think about ventilation strategies that reduce ice dams. On low-slope additions, consider fresh membrane and tapered insulation to shed water away from skylights. The upfront roof installation cost is higher, but the long-term reduction in leaks, energy waste, and callbacks often justifies it.

Quick checklist: prioritize your next steps

• Document the leak path with photos inside and outside, including the uphill drainage area.
• Schedule a focused roof inspection that includes a controlled water test at the skylight.
• Decide between targeted reflashing and replacement based on roof age and skylight condition.
• Plan preventive maintenance: clear gutters, improve ventilation, and seal attic air leaks.

FAQ: straight answers about skylight leaks and repairs

Below are common questions homeowners ask when they move from frustration to action. Short, practical answers help you judge the right level of response.

How can I tell if the leak is from the skylight or just condensation?

Condensation forms evenly on the cool interior surfaces during cold spells and often drips from the lowest points. True leaks usually leave asymmetrical stains at corners or sides, and they appear after rain or melt events, not just on cold mornings. A controlled water test on a dry day helps separate the two.

Is patching with caulk a waste of money?

Caulk is a gasket, not a roof. It can buy time for small gaps, but it fails under UV and thermal movement. If the flashing sequence is wrong or the underlayment is missing around the curb, only a proper reflashing will hold. Use sealants sparingly and only as part of a manufacturer-approved detail.

Why do bids for the same skylight repair vary so much?

Scope and access. One bid may include removing and replacing shingles in a full step-flashing sequence, ice and water membrane, sheathing repairs, and a new head flashing. Another might price a surface seal. Roof height, pitch, and complexity matter too, as does whether the work is part of a larger project with shared setup costs.

Can I repair a skylight on a low-slope roof the same way as on shingles?

No. Membrane roofs rely on welded seams and compatible primers. A shingle-style step flashing will not work on TPO, EPDM, or PVC. Use the membrane manufacturer’s curb details and, when needed, metal counterflashing. Mixing systems risks leaks and voided warranties.

Will insurance cover skylight leak repairs?

Insurers typically cover sudden events such as hail damage or wind-driven debris, not wear and tear, UV degradation of roofing materials, or improper installation. Document storm dates, keep photos, and involve a contractor who can provide a clear cause of loss. If you choose repair instead of replacement, confirm with the adjuster to avoid disputes.

How long should a proper skylight repair last?

With correct flashing, underlayment, and good ventilation, a skylight repair should match the remaining life of the surrounding roof. On a younger roof, that can mean 10 years or more. On an older roof nearing replacement, consider the repair a bridge to the upcoming reroof.

Why a roof repair is rarely just a roof repair

Skylight leaks are powerful teachers. They force a close look at how your roof handles water, heat, and airflow. Fixing the drip at the drywall is the easy part. The lasting solution involves correct flashing geometry, compatible materials, and the sometimes unglamorous work of improving insulation and ventilation. Get those right, and you protect the whole roof assembly, not just the opening.

If you want local help, start with verified listings. For example, you can review a contractor’s service footprint to ensure they actually work your city, such as roofers serving Eden Prairie. When you are ready to compare, you can also click here to view a professional profile with project photos and contact details. Vet a couple of options, ask skylight-specific questions, and insist on manufacturer-correct details. That is how a one-time leak becomes a long-term win for your home.