Skylight Leaking When Raining | Pioneer Roofing St. Louis

Why Your Skylight Leaks Every Time It Rains in St. Louis

You installed a skylight for natural light. Now every storm turns it into a water feature you did not ask for.

St. Louis receives an average of 42 inches of rain annually, with intense spring thunderstorms that test every vulnerable point on your roof. When water drips from your skylight during these downpours, the problem is almost never the skylight glass itself. The failure is in the waterproofing layers around it.

Most skylight leaking during storms traces back to three culprits. The flashing system that bridges your skylight to the roof deck deteriorates from freeze-thaw cycles that are brutal in our climate. The curb that elevates your skylight above the roof plane cracks as your home settles on St. Louis clay soil. The seal between the skylight frame and curb fails after years of thermal expansion and contraction.

You might notice water dripping from the skylight frame during heavy rain, or you might see staining on the drywall around your roof window weeks after the last storm. Both signal that water is penetrating past the primary weather barrier and tracking through your roof assembly.

Some homeowners in neighborhoods like Soulard and Tower Grove see leaking skylight flashing problems accelerate because of the age of their homes. Historic structures built before modern flashing standards often have skylights retrofitted with inadequate waterproofing details. When a roof window starts leaking, the water does not just damage ceilings. It saturates insulation, rots framing lumber, and creates conditions for mold growth in your attic space.

The longer water drips from your skylight, the more expensive the repair becomes.

Why Your Skylight Leaks Every Time It Rains in St. Louis

How We Fix Skylight Leaks Permanently

We do not guess about why your skylight leaks in heavy rain. We diagnose first.

Our inspection starts with removing the interior trim and examining the rough opening for water staining patterns. These patterns tell us exactly where water enters. We then access the exterior and systematically evaluate every component in the skylight assembly. The step flashing along the sides. The head flashing at the top. The saddle flashing that diverts water around the uphill side of the curb. The counter-flashing that covers the step flashing edges.

We check the curb itself for rot or separation from the roof deck. We inspect the skylight glazing seals and the weep holes that allow condensation to drain. We look for ice dam damage on the uphill side, common in St. Louis winters when snow melts and refreezes at roof edges.

Once we identify the failure point, we rebuild the waterproofing system correctly. This usually means removing the skylight unit entirely, replacing deteriorated curb framing, and installing new flashing integrated with your underlayment and shingle courses. We use metal step flashing, not the cheaper plastic alternatives that crack in sunlight. We extend the underlayment up the curb sides and lap it properly with the head flashing.

For roofs with low pitch, we add a secondary water barrier and increase the curb height to prevent water from wicking under shingles during wind-driven rain. For older homes with unusual framing, we often custom-fabricate flashing components to match the existing roof geometry.

We also address the drainage plane around your skylight. Water must flow around the unit, not pool against it. We verify that shingles are properly cut and that the exposure matches adjacent courses so water does not track sideways into the rough opening.

What Happens When You Call About a Leaking Skylight

Skylight Leaking When Raining in St. Louis – Expert Diagnosis and Permanent Repair

Interior and Exterior Inspection

We examine your ceiling and attic for water stains to trace the leak path, then access your roof to inspect all flashing components, the curb assembly, and the skylight unit itself. This dual approach reveals whether you need a flashing repair, full skylight replacement, or curb reconstruction. Most skylight leaking during storms involves flashing failure, not skylight failure, which changes the scope and cost significantly.

Flashing System Rebuild

We remove shingles in a controlled area around your skylight and temporarily lift the unit to access the curb and deck. We replace any rotted framing, install new step flashing and head flashing lapped with underlayment, and rebed the skylight with fresh sealant. For chronic leaks, we add a secondary barrier and extend flashing higher up the curb. This phase requires precision because improper lapping order will still leak.

Final Integration and Testing

We reinstall shingles around the skylight, ensuring each course overlaps the flashing correctly and that no exposed nails compromise the weather barrier. We inspect the interior rough opening, replace any damaged insulation, and confirm that the drainage plane directs water away from the curb. Before we leave, we discuss maintenance practices like clearing debris from the uphill side to prevent water pooling during future storms.

Why St. Louis Homeowners Trust Us With Skylight Repairs

Call Now - (314) 417-7774

Skylight leaks are not like replacing shingles. They require an understanding of how water moves across a roof plane, how flashing integrates with different roofing materials, and how to detail the transition between a flat skylight curb and a sloped roof deck.

We have repaired skylights on everything from the brick bungalows in Dutchtown to the Victorian mansions in Lafayette Square. Each architectural style presents unique challenges. Older homes often have skylight curbs built directly into the roof deck without proper flashing, a method that worked when roofs were replaced every 15 years but fails on modern 30-year shingles. Historic district homes require flashing materials and methods that meet preservation standards while still stopping leaks.

Our crews understand St. Louis weather patterns. We know that spring storms deliver high volumes of water in short periods, overwhelming undersized flashing systems. We know that winter ice dams form on north-facing roof planes and force water under shingles and into skylight curbs. We account for these conditions in every repair.

We also understand the building codes that apply to skylight installations in St. Louis County and the city. Curb height requirements, flashing material specifications, and structural load considerations all affect how we approach a repair. A roof window leaking because of code violations from a previous installation requires more than just patching the leak. It requires bringing the assembly into compliance so you do not face problems during a future home sale or insurance claim.

When you call us about a leaking skylight, you are not getting a roofer who will slap some caulk on the problem and hope it holds. You are getting a diagnostic approach that identifies the root cause and fixes it correctly.

What You Can Expect From Our Skylight Leak Repair Service

Response Time and Scheduling

We schedule inspections within two business days of your call. If your skylight is actively leaking and causing interior damage, we can often arrange a same-day temporary tarp to stop water intrusion while we prepare for the full repair. Most skylight flashing repairs take one to two days depending on the extent of framing damage and whether we need to fabricate custom flashing components. We coordinate around forecasts to avoid tearing into your roof ahead of rain events that would compromise the repair.

The Inspection Process

Our inspection includes interior attic access to examine the rough opening and exterior roof access to evaluate all flashing components. We photograph the failure points and explain what we find in plain terms. You will understand whether your leak is a simple flashing issue or whether the curb has rotted and needs reconstruction. We provide a written estimate that breaks down materials and labor so you know exactly what you are paying for. There are no surprise charges for discovering additional damage once we start work.

Repair Quality and Materials

We use metal step flashing and head flashing that matches the gauge and material of your existing roof flashing. We do not use tar or generic caulk as primary waterproofing. Every flashing component is lapped correctly with your underlayment and shingle courses according to manufacturer specifications and building code. If we replace curb framing, we use pressure-treated lumber that will not rot when exposed to moisture. The finished repair is invisible from the ground and integrates seamlessly with your existing roof.

Workmanship and Follow-Up

We stand behind our skylight repairs. If your skylight leaks again within the first year after our work, we return to diagnose and correct the issue at no charge. We also provide guidance on maintaining your skylight system, including clearing debris from the uphill side and inspecting the sealant bead around the skylight frame every few years. When done correctly, a skylight flashing repair should last as long as your roof itself. We also offer full roof inspections if you are concerned about other potential leak points.

Call Now - (314) 417-7774

Frequently Asked Questions

You Have Questions,
We Have Answers

Why is my skylight leaking in heavy rain? +

Heavy rain exposes weaknesses in your skylight's waterproofing system. The most common culprits are damaged flashing, deteriorated sealant around the frame, or cracked glazing. St. Louis experiences intense summer storms and freeze-thaw cycles that break down flashing over time. Water pools on flat or low-slope skylights during downpours, finding any gap in the seal. Improper installation also causes leaks, especially if the skylight wasn't integrated correctly with your roof's underlayment. If you see water stains or drips during storms, the problem will worsen. Address it quickly before water damages your ceiling, insulation, or framing.

Is a leaking skylight covered by homeowners insurance? +

Coverage depends on what caused the leak. If storm damage like hail or wind tore the flashing or cracked the skylight, most St. Louis homeowners policies cover repairs. You need to document the storm event and damage quickly. If the leak comes from wear, age, or poor maintenance, insurance typically denies the claim. Insurers view gradual deterioration as your responsibility. Review your policy's exclusions and take photos immediately after storm damage. An inspection helps determine if the cause qualifies as a covered peril. File claims promptly because delayed reporting can reduce your payout or trigger denial.

How to fix a skylight that is leaking? +

First, identify the leak source. Check the flashing where the skylight meets your roof. Remove old sealant and apply roofing cement or high-grade polyurethane caulk around the frame. If flashing is bent or missing, replace it completely. For cracked glass or acrylic, replace the entire dome or pane. Inspect the underlayment beneath the skylight for water damage. In St. Louis, ice dams and thermal expansion stress skylights, so check for hairline cracks. Temporary fixes like tarps work during emergencies, but permanent repairs require proper flashing, weatherproofing, and integration with your roof system. Hire a professional if you lack roofing experience.

Can skylights be resealed? +

Yes, you can reseal skylights if the frame and glass remain intact. Remove all old caulk with a scraper or utility knife. Clean the surfaces with isopropyl alcohol to remove debris and oils. Apply a continuous bead of polyurethane or silicone sealant designed for exterior use. Press firmly to eliminate air pockets. Resealing works for minor leaks caused by dried-out caulk, but it does not fix damaged flashing or structural issues. In St. Louis, temperature swings degrade sealant faster than in milder climates. Expect to reseal every five to seven years. If leaks persist after resealing, the problem likely involves flashing or roof deck damage.

Does homeowners insurance cover roof leaks from storms? +

Storm damage typically qualifies for coverage if wind, hail, or falling debris caused the leak. Most St. Louis policies cover sudden, accidental damage from severe weather events. You must prove the storm directly caused the roof failure. Take photos, note the storm date, and get an inspection quickly. Policies exclude gradual leaks from wear, age, or missing shingles you ignored. If your roof was already compromised before the storm, insurers may deny the claim. Deductibles apply, so small repairs might cost less than filing. Review your policy's wind and hail provisions, especially after spring and summer storms common to the region.

How much does it cost to fix a leaky skylight? +

Repair costs range based on the leak's cause and severity. Resealing a skylight runs a few hundred dollars. Replacing damaged flashing costs more due to labor and materials. If the skylight dome or glass cracked, expect higher costs for parts and installation. Full skylight replacement becomes necessary when frames warp or multiple components fail. St. Louis contractors factor in roof pitch, skylight size, and accessibility. Emergency repairs during active leaks cost more than scheduled maintenance. Get multiple quotes and ensure the estimate includes flashing, underlayment, and sealant. Delaying repairs increases costs when water damages ceilings, insulation, or framing beneath the skylight.

How St. Louis Storms Test Skylight Flashing Systems

St. Louis sits at the confluence of multiple weather systems that create intense, fast-moving storms. Spring thunderstorms deliver high rainfall rates that overwhelm flashing systems designed for moderate rain. Winter freeze-thaw cycles cause metal flashing to expand and contract, breaking sealant bonds and opening gaps where water can enter. The clay soil common throughout the metro area causes homes to settle unevenly, which can crack skylight curbs and separate flashing from the roof deck. These conditions make leaking skylight flashing more common here than in drier or more stable climates.

Homes in historic neighborhoods like Shaw and Compton Heights often have skylights added decades after original construction. These retrofits were not always detailed correctly because older building codes did not specify flashing requirements as precisely as modern standards do. If you live in a home built before 1980 and your roof window is leaking, there is a strong chance the original installation lacked proper step flashing or used materials that have deteriorated beyond their service life. Local expertise matters because we understand these legacy installation methods and know how to correct them without compromising your roof structure.

Skylight Leaking When Raining in St. Louis – Expert Diagnosis and Permanent Repair

Why Your Skylight Leaks Every Time It Rains in St. Louis

How We Fix Skylight Leaks Permanently