Skylight leak repair in San Antonio why it happens and how to fix it

Skylight leak repair in San Antonio why it happens and how to fix it starts with one fact: most skylight leaks come from failed flashing or deteriorated seals, not from the glass itself. In San Antonio's climate - where summer attic temperatures routinely hit 140°F and hail season runs April through June - the sealant and flashing around a skylight take a beating. The good news is that most leaks are fixable without replacing the entire unit. This post breaks down the real causes we see across San Marino and greater San Antonio, walks through the repair process, and gives you honest 2026 pricing so you can decide whether to DIY or call a pro.

Why Does My Skylight Leak in San Antonio TX?

Your skylight leaks in San Antonio because the materials that keep water out - flashing, sealant, and gaskets - degrade faster here than in cooler climates. The leak is almost never the glass pane. It's the perimeter. We've torn out dozens of skylights across Bexar County, and the pattern is consistent: the curb flashing has pulled away, the butyl tape has dried to a crisp, or the weep holes are clogged with debris. San Antonio's intense UV index - often 11+ from May through September - cooks sealant until it cracks. Then a single heavy rain pushes water sideways under the flashing and into your attic.

Here's what we find on nearly every Roof Leak Inspection in San Marino, Texas that involves a skylight:

• Failed flashing. The metal or membrane flashing that ties the skylight curb to the roof field separates from the roofing material. This is the number one cause, especially on older homes in San Marino where original 1990s flashing is now brittle.
• Cracked or missing sealant. The bead of polyurethane or silicone around the skylight frame shrinks and pulls away. A 1/16-inch gap is enough to let in water during a hard Texas thunderstorm.
• Clogged weep holes. Skylights have small drainage channels. When pine needles, dirt, or roof grit block them, water backs up under the frame and finds a path inside.
• Condensation, not a leak. In winter, warm moist air from your home hits the cold skylight glass and forms droplets. That's not a roof leak - it's a ventilation issue. But it can look identical to a leak from below.
• Hail damage. A 1-inch hailstone can crack the acrylic dome or dent the metal flashing. San Antonio sits in a hail alley; we see this most often after spring storms.

If you're seeing water stains on the ceiling near the skylight, the leak has likely been active for weeks. Water travels along framing before it drips, so the entry point is often 2-3 feet away from the stain. That's why guessing from inside rarely works.

How to Fix a Skylight Leak in San Antonio Texas

Fixing a skylight leak in San Antonio Texas means resealing the flashing, replacing failed gaskets, and clearing the drainage path - in that order. You don't start with a tube of caulk. You start by finding the actual entry point. On a typical repair, we spend 20 minutes diagnosing and 90 minutes fixing. Here's the process we use:

1. Water test. We spray the skylight from a ladder while a second person watches from inside the attic. This pinpoints the leak in minutes instead of guessing.
2. Remove old sealant and flashing. We pull back the roofing material around the curb, remove the failed flashing, and clean the surface. Skipping this step is why DIY caulk fixes fail within a year.
3. Install new flashing. We use new step flashing or a skylight-specific flashing kit, sealed with butyl tape and a high-grade polyurethane sealant rated for Texas UV. This is the permanent fix.
4. Replace gaskets and seals. The gasket between the glass and the frame hardens over time. A new gasket costs $15-$40 and takes 15 minutes to install.
5. Clear weep holes and channels. We flush the drainage path and confirm water exits where it should.
6. Final water test. We repeat the spray test to confirm the leak is gone before we pack up.

If the skylight itself is cracked - the glass or acrylic dome - you're looking at a replacement, not a repair. But that's maybe 15% of the calls we run. Most leaks are flashing and sealant issues. For a broader look at how we handle roof leaks of all types, see our Roof Leak Repair in San Marino, Texas page.

Skylight Leak Repair Cost in San Antonio TX

Skylight leak repair cost in San Antonio TX runs $350 to $900 for most residential repairs in 2026, with a typical job landing around $550. The price depends on access, roof pitch, and whether the flashing needs full replacement. A simple reseal - new sealant and gaskets - is on the low end. Full flashing replacement with new step flashing and underlayment repair pushes toward the high end. If the skylight unit itself is cracked and needs replacement, expect $1,200 to $2,800 installed, depending on size and whether it's a fixed or vented unit.

Here's a rough breakdown for 2026:

• Diagnostic and water test: $75-$150 (often waived if you proceed with the repair)
• Reseal and gasket replacement: $350-$500
• Flashing replacement: $500-$900
• Skylight replacement (unit + labor): $1,200-$2,800

We give you a flat price before we start. No hourly surprises. If you're in San Marino and want a number for your specific roof, we can usually get someone out the same week. For urgent leaks - the kind that are dripping into a bucket right now - our Emergency Roof Leak Repair in San Marino, Texas team can often be there the same day.

Common Mistakes to Avoid

The biggest mistake homeowners make is caulking over the old sealant without removing it. New caulk won't bond to old, chalky sealant. It peels within months, and you're back to a leak. We see this constantly - a tube of silicone smeared around the skylight frame, already cracking. The fix is to strip the old material down to clean metal or membrane, then apply fresh sealant.

Other mistakes we see:

• Sealing the weep holes. Those small channels are supposed to let water out. Caulking them traps water inside the frame and makes the leak worse.
• Using the wrong sealant. Standard silicone breaks down under Texas UV in 12-18 months. You need a polyurethane or hybrid sealant rated for high movement and UV exposure.
• Ignoring the attic side. If you don't check the underside of the roof deck, you might miss that the leak has already rotted the sheathing. A $500 repair becomes a $2,000 repair when the decking is soft.
• Walking on the skylight. Acrylic domes get brittle after years of UV. One wrong step and you're replacing the unit.

If you're not comfortable on a roof - and most people shouldn't be - don't risk it. A fall from a one-story roof can put you in the hospital. We handle the ladder work.

When to Call a Professional

Call a professional when you've resealed once and the leak comes back, when you see sagging or discolored ceiling drywall, or when water is actively dripping during a storm. Those are signs the problem is deeper than a surface seal. We've been called to San Marino homes where a homeowner spent three weekends trying to chase a leak that turned out to be a cracked vent boot 4 feet away from the skylight. The water was traveling along a rafter.

Our team at Roof Leak repairer San Antonio handles skylight leaks every week. We start with a proper Roof Leak Detection in San Marino, Texas - water test, attic inspection, moisture meter - so we're fixing the actual source, not a symptom. If you want to prevent the next leak before it starts, ask about our Roof Leak Prevention in San Marino, Texas service. We'll check your flashing, sealant, and drainage and give you a straight assessment.

Frequently Asked Questions

Why does my skylight leak in San Antonio Texas?

Your skylight leaks in San Antonio Texas because UV exposure and heat degrade the flashing and sealant around the frame. The glass itself rarely fails. After 10-15 years, the original butyl tape and sealant crack, letting water slip under the flashing during heavy rain.

How do I fix a skylight leak in San Antonio?

To fix a skylight leak in San Antonio, remove the old sealant and flashing, install new step flashing with butyl tape and polyurethane sealant, replace the gasket, and clear the weep holes. A water test before and after confirms the repair. Most jobs take 2-3 hours.

How much does skylight leak repair cost in San Antonio TX?

Skylight leak repair in San Antonio TX costs $350-$900 in 2026, with most homeowners paying around $550. Simple reseals are on the low end; full flashing replacement is higher. Skylight unit replacement runs $1,200-$2,800 installed.

Can a skylight leak be repaired without replacement in San Antonio?

Yes, about 85% of skylight leaks in San Antonio are repaired without replacing the unit. Flashing, sealant, and gasket repairs solve the problem. Replacement is only needed when the glass or acrylic dome is cracked or the frame is rotted.

How long does skylight leak repair take?

Most skylight leak repairs take 2-4 hours on site. If flashing replacement is needed and the roof pitch is steep, plan for a full half-day. We schedule a single visit for diagnosis and repair whenever possible.

Get Help with Roof Leak Repair in San Marino

If your skylight is leaking, we can stop it. Our team serves San Marino and the greater San Antonio area with same-week scheduling and flat-rate pricing. Call us at 210-939-5773 and we'll get a technician on your roof to find the source and fix it right the first time.