How to tell if a skylight leak needs repair or replacement

A skylight leak needs repair if the glass, frame, and curb are structurally sound and the water is entering through failed sealant, flashing, or a worn gasket. It needs replacement if the glass is cracked, the frame is warped or rusted through, the seal between the glass and frame has failed, or the unit is more than 20 years old and has leaked more than once. That's the short version. The rest of this post walks you through the specific signs we look for on Knoxville roofs, what each fix costs in 2026, and how to decide which path makes sense for your home.

Skylight leak repair or replacement Knoxville TN is a decision that comes down to three things: the age of the unit, the condition of the frame and flashing, and whether the leak is coming from the skylight itself or from the roof around it. We've been on hundreds of Knoxville roofs where the homeowner was sure the skylight was shot, and the actual problem was a $180 flashing repair. We've also seen the opposite - a unit that looked fine until we pulled the curb and found rotted framing underneath.

If you want a same-week assessment, our team handles Roof Leak Repair Knoxville TN across the city and can tell you in one visit whether you're looking at a repair or a replacement.

Repair or replacement? The short answer

Repair is the right call when the leak traces back to a seal, a flashing detail, or a gasket - something that can be replaced without pulling the whole unit. Replacement is the right call when the skylight itself has failed: cracked glass, a frame that's rusted or warped, fogging between the panes, or a curb that's rotted.

Here's the rule of thumb we use: if the unit is under 15 years old and this is the first leak, repair it. If it's over 20 years old, or if we've been out twice for the same skylight, replace it. Between 15 and 20 years, it depends on the brand and how the unit was installed.

One more thing: a skylight leak is not always a skylight problem. On a lot of Knoxville homes, water shows up at the skylight because the flashing around the curb has pulled away, or because the roof-to-wall intersection above it is leaking and the water is traveling down the rafter. We confirm the source before we quote anything.

How do I know if my skylight needs repair or replacement in Knoxville TN?

You know it's time to replace when the glass is cracked, the frame is rusted or warped, or you can see condensation between the panes - those are unit failures, not seal failures. You know it's a repair when the glass and frame are intact and the water is coming in around the edges.

Walk up to the skylight on a dry day and look at it. Here's what to check:

• Glass: Any crack, chip, or cloudiness between the panes means the sealed unit is gone. Replacement.
• Frame: Run your hand along the interior frame. Soft spots, bubbling paint, or rust stains mean moisture has been sitting there. Replacement is likely.
• Flashing: Look at the metal flashing where the skylight meets the roof. If it's lifted, cracked, or covered in old tar, that's a repair - and a cheap one.
• Gaskets and seals: The rubber gasket around the glass dries out and shrinks. If it's brittle or pulling away, we can often re-seal it.
• Ceiling stains: A brown ring on the drywall below tells you water has been getting in for a while. The size of the stain tells you how long.

If you're seeing a stain but the skylight looks fine from inside, the leak is probably in the roof around it. That's when we bring out the roof leak detection and repair Knoxville TN equipment - moisture meters, hose testing, and sometimes a thermal camera - to trace the water back to its actual entry point.

The five failure points we see on Knoxville skylights

Skylights fail in predictable places, and knowing which one is leaking tells you whether you're looking at a repair or a replacement.

1. The flashing around the curb

This is the most common leak we find, and it's almost always a repair. The flashing is the metal that bridges the gap between the skylight curb and the roof surface. On Knoxville roofs, we see it pull loose after a few summers of expansion and contraction. Re-flashing a skylight typically runs $250 to $550.

2. The seal between the glass and frame

The factory seal that holds the glass into the frame dries out over time. If the seal is the only problem, we can sometimes re-glaze the unit. But if the seal has been failing for years, water has been sitting in the frame, and the frame is probably compromised. That's a replacement.

3. Cracked or fogged glass

A crack in the glass is an automatic replacement. Fogging between the panes means the sealed unit has lost its argon fill and the desiccant is saturated - also a replacement. There's no repair for a failed sealed unit.

4. The curb itself

The curb is the wooden box the skylight sits on. If it's rotted, we have to rebuild it before we can install anything new. Curb rebuilds add $300 to $700 to the job, depending on how much framing is damaged.

5. The roof around the skylight

Sometimes the skylight is fine and the leak is in the shingles or underlayment next to it. This is common on roofs over 15 years old. In that case, you're looking at a asphalt shingle roof leak repair Knoxville TN, not a skylight replacement.

Skylight leak repair cost vs. replacement cost in Knoxville TN

Typical 2026 pricing in Knoxville runs $250 to $650 for a skylight leak repair and $1,200 to $3,500 for a full replacement, depending on unit size and whether the curb needs rebuilding.

Here's how the numbers break down:

• Re-sealing the flashing: $250-$550
• Replacing the gasket or seal: $300-$600
• Re-glazing a fixed skylight: $450-$900
• Replacing a fixed skylight (standard size): $1,200-$2,200
• Replacing a vented or operable skylight: $1,800-$3,500
• Curb rebuild (if needed): add $300-$700
• Interior drywall repair: $150-$500, usually handled separately

Those ranges assume a standard 2x4-foot or 2x3-foot unit on a pitched roof with reasonable access. A large custom skylight, a unit on a steep roof, or one that requires scaffolding will run higher.

We give you the number before we start. If we open up the curb and find rot that changes the scope, we stop and talk to you before we do anything else.

Repair makes sense when...

Repair makes sense when the skylight is structurally sound and the leak is coming from a seal, a flashing detail, or the roof around it. Those are the jobs where a few hundred dollars solves the problem for years.Specifically, repair is the right call when:

• The unit is under 15 years old.
• The glass is clear and uncracked.
• The frame is solid - no soft spots, no rust.
• The leak only shows up during heavy, wind-driven rain.
• You've never had this skylight leak before.
• The water is entering at the flashing, not the glass.

We see a lot of these on the older homes in Roof Leak Repair in Fountain City, where skylights were added during renovations in the 1990s and early 2000s. Most of those units still have good glass and frames - they just need the flashing re-done and the seals refreshed.

Replacement makes sense when...

Replacement makes sense when the skylight itself has failed - cracked glass, a rotted frame, a failed sealed unit, or a unit that's already been repaired twice. At that point, you're throwing money at a problem that's going to keep coming back.

Replace the skylight when:

• The glass is cracked, chipped, or fogged between the panes.
• The frame is warped, rusted, or soft to the touch.
• The unit is over 20 years old.
• It's leaked more than twice in the last five years.
• You can see daylight or feel air moving around the frame.
• The curb is rotted and needs to be rebuilt anyway.

When we replace a skylight, we install a modern unit with a better seal and a low-E coating. That cuts heat gain in the summer and condensation in the winter - both real issues in Knoxville's climate. If you're already paying for the labor, upgrading the unit usually adds $200 to $500 to the total and pays it back in energy savings.

If the leak turns out to be storm-related - hail cracked the glass, or wind lifted the flashing - that's a different conversation. We handle storm damage roof leak repair Knoxville TN and can document the damage for your insurance claim.

Common mistakes we see homeowners make

The biggest mistake is sealing the leak from the inside with caulk or roof tar. That traps moisture in the framing and turns a $400 repair into a $2,000 curb rebuild.

Other mistakes we run into:

• Assuming the skylight is the problem. On a lot of Knoxville roofs, the leak is actually at the chimney or a roof penetration nearby, and the water just shows up at the skylight because that's the low point.
• Waiting until the ceiling stains get big. A small stain means a small leak. A sagging, brown ceiling means the drywall, insulation, and possibly the framing are wet.
• Hiring whoever's cheapest. A $150 flashing repair that uses the wrong sealant will fail within a year. We've re-done plenty of those.
• Replacing the skylight when the roof is the problem. If the shingles around the skylight are shot, a new skylight won't stop the leak.
• Ignoring the second leak. If a skylight leaks once, it'll leak again. The second leak is the one that tells you the unit is done.

We also see homeowners try to fix skylight leaks themselves with silicone from the hardware store. That works for about six months. The problem is that silicone doesn't bond well to the older flashing materials we see on Knoxville roofs, and it traps water against the metal, which speeds up corrosion.

When to call a professional

Call a professional when you can't find the source, when the leak has been going on for more than a few weeks, or when you're not sure whether the skylight or the roof is the problem. Water travels. What looks like a skylight leak is often a flashing leak two feet away.

We handle skylight leak repair and replacement across Knoxville. Our technicians get on the roof, trace the water to its actual entry point, and give you a straight answer on whether you're looking at a repair or a replacement. If it's a repair, we do it that day in most cases. If it's a replacement, we schedule it and give you a written price before we order the unit.

If you're in Roof Leak Repair in West Knoxville or anywhere else in the city, we can usually get out within a few days. Same-day service is available for active leaks.

Frequently Asked Questions

How do I know if my skylight needs repair or replacement in Knoxville TN?

If the glass is clear and uncracked and the frame is solid, it's a repair - usually $250 to $650. If the glass is cracked, fogged between the panes, or the frame is rusted or soft, it's a replacement. Units over 20 years old almost always need replacement.

How much does skylight leak repair cost in Knoxville Tennessee?

Most skylight leak repairs in Knoxville run $250 to $650 in 2026. Re-flashing the curb is the most common fix and typically costs $250 to $550. If the gasket or seal needs replacing, expect $300 to $600. We give you the price before we start.

Who fixes skylight leaks near me in Knoxville?

Knoxville Roofing Company repairs and replaces skylights across Knoxville, including Fountain City, West Knoxville, South Knoxville, and Halls Crossroads. We trace the leak to its source first, then tell you whether it's a repair or a replacement. Call (865) 2988-904.

Can I just seal a skylight leak from the inside?

No. Sealing from the inside traps moisture in the frame and curb, which leads to rot. The leak has to be fixed from the roof side. Interior caulk buys you a few months at best and usually makes the eventual repair more expensive.

How long does a skylight replacement take?

A standard skylight replacement takes three to five hours. If the curb needs rebuilding, plan on a full day. We handle the roof work and can coordinate the interior drywall repair if you need it.

Get help with Roof Leak Repair in Knoxville

If your skylight is leaking, we'll tell you straight whether it needs a repair or a replacement - and we'll give you the price before we start. Call Knoxville Roofing Company at (865) 2988-904 to schedule a skylight leak inspection.