Why Skylights Leak — and Why It Gets Worse Over Time
Skylights are one of the most common sources of roof leaks in Central Texas homes. They sit directly in the roof field, penetrating the waterproofing system at a point that experiences concentrated water flow, extreme temperature cycling, and constant UV exposure. Unlike a simple shingle surface, a skylight involves the intersection of multiple materials — glass or acrylic, aluminum or wood framing, metal flashing, caulk, and roofing materials — each of which expands and contracts at different rates with temperature changes.
In Central Texas, where summer roof surface temperatures routinely exceed 150°F and winter cold snaps can drop temperatures 60–70°F in 24 hours, these thermal cycling stresses are extreme. Sealants crack. Flashing separates. Frame materials fatigue. Over time, the waterproofing at the skylight perimeter degrades to the point where rain finds its way in — first as a slow seep during heavy downpours, then as a regular drip with any significant rain event.
The water you see dripping inside your home represents the downstream end of a leak path that may originate several inches or feet from where you see the water. Skylights that "leak at the frame" are often actually failing at the step flashing several inches up the roof from the visible frame. This is why skylight leak diagnosis requires a professional — caulking over the visible gap rarely solves the actual problem.
Common Skylight Problems We Fix
Failed Step Flashing
The step flashing along the sides of the skylight is the most common leak source. Individual flashing pieces at each shingle course can lift, rust, or develop gaps over time — allowing water to bypass the entire flashing system.
Counter Flashing Separation
The counter flashing that laps over the step flashing at the skylight frame seals the upper edge of the flashing system. When this separates due to thermal movement or fastener failure, water runs directly behind the flashing.
Cracked or Crazed Lens
Acrylic dome skylights are vulnerable to impact cracking (from hail or debris) and crazing — a network of surface micro-cracks caused by UV degradation and thermal stress. Crazed acrylic loses its clarity and waterproofing integrity over time.
Condensation Between Panes
Double-pane skylight units can develop failed seals that allow moisture to migrate between the glass panes, creating a foggy or streaked appearance that doesn't wipe off. This isn't a roof leak — it's a failed insulating glass unit (IGU) that needs replacement.
Frame Deterioration
Wood-framed skylights are particularly vulnerable to rot in our climate. Metal frames can corrode, especially aluminum in contact with incompatible metals. A deteriorated frame compromises the seal between the unit and the surrounding roofing system.
Lower Flashing (Apron) Failure
The kick-out or apron flashing at the lower edge of the skylight directs water away from the frame onto the shingles below. When this fails, water pools at the lower edge and finds its way under the frame.
Types of Skylights We Service
Fixed Skylights
The most common residential skylight — non-opening units that provide daylight but no ventilation. We repair flashing, seals, and lenses, and replace complete units when needed.
Vented/Opening Skylights
Skylights that open for ventilation add complexity at the hinge and weatherstripping system. We repair the flashing system, seals, and mechanical opening components.
Tubular Skylights (Sun Tunnels)
Flexible or rigid tube systems that channel daylight from a small dome on the roof to a diffuser in the ceiling. We install new tubular skylights and repair flashing on existing units.
Velux, FAKRO, and Custom Units
We service all major skylight brands including Velux, FAKRO, Wasco, Sun-Tek, and custom site-built units. Brand-specific flashing kits are available for most major manufacturers.
Repair vs. Replace: Our Honest Assessment
We'll always give you an honest recommendation based on your specific situation. Here's how we think about the repair vs. replace decision:
Repair Makes Sense When:
- • The skylight unit itself is sound (no cracked lens, solid frame)
- • The unit is less than 15 years old
- • The leak is clearly isolated to flashing or sealant
- • The skylight is a premium unit worth preserving
Replacement Makes More Sense When:
- • The unit is 15+ years old with multiple failure points
- • The lens is cracked, crazed, or has failed IGU seals
- • The frame shows structural deterioration
- • You're also replacing the surrounding roof
If you're scheduling a full roof replacement, that's an ideal time to replace skylights simultaneously — the cost of installing a new skylight is lower when the surrounding roof is already being worked on, and you get a fresh start with proper flashing integration.
New Skylight Installation in Killeen
Whether you're adding a skylight to an existing roof or replacing an old unit, proper installation is everything. A skylight that is flashed and waterproofed correctly will provide decades of leak-free service. The most common reason skylights fail shortly after installation is improper flashing integration with the surrounding roof system.
We recommend ENERGY STAR-rated low-e glass skylights for Central Texas homes, which reduce solar heat gain by 40–70% compared to standard glass — a meaningful comfort and energy efficiency improvement. For post-hail-damage replacements, impact-rated glazing is available and often qualifies for insurance coverage under your storm damage claim. Have questions? Schedule your free estimate or check our free roof inspection page for details on what our comprehensive assessment covers.