By The Roofing Brief Team. Last reviewed: October 2026.
Roof skylight replacement means removing a failed or dated skylight and installing a new unit, and the single biggest decision is timing: replace during a reroof and the surrounding shingles are already off, so you pay for one flashing job instead of two. A full skylight replacement costs $800 to $2,400 on average per HomeGuide’s skylight repair and replacement cost guide (February 5, 2026), close to the $800 to $2,200 average in VELUX’s replacement cost guide, while replacing only a cracked dome on a curb unit runs $350 to $900 on HomeGuide’s figures. HomeGuide gives skylights a 15 to 40 year replacement interval, and VELUX says its units often last 30 years or longer.
Two code rules shape every replacement. IRC R308.6.8 requires a unit skylight on a roof pitched below 3:12 to sit on a curb at least 4 inches above the roof plane unless the maker’s instructions say otherwise, and IRC R308.6.9 requires the new unit to carry a label showing compliance with AAMA/WDMA/CSA 101/I.S.2/A440 (2021 IRC Chapter 3).
Signs it is time to replace a roof skylight
Replace a roof skylight when the glazing seal has failed, the flashing leaks repeatedly, or the unit is past 20 years old. Age is the most common trigger, and poor original installation is the second. A skylight that fogs between the panes or drips after every storm is telling you the sealed unit or the flashing has reached the end of its service life.
- Fogging or condensation between the glass panes. The insulated glazing seal has failed and cannot be resealed. VELUX covers glass seal failure for 20 years on its deck- and curb-mounted units, per the VELUX 2025 residential skylights catalog, so check the install date before paying for a new unit.
- Repeat leaks around the frame. If the leak returns after a patch, the flashing or the sealed unit is done, not the caulk.
- A cracked, yellowed, or crazed acrylic dome. VELUX lists discoloration from sunlight, mildew stains from trapped moisture, leaks and condensation around the panes as the signs to replace a bubble skylight, on its VELUX replacement page.
- Age past 20 years. Older units often use single-pane or early double glazing. For comparison, the 2021 IECC caps skylight U-factor at 0.55 in climate zones 3 to 8, 0.65 in zone 2 and 0.75 in zone 1 for new homes (Table R402.1.3, per PNNL’s Building America Solution Center table).
- Water stains on the interior light shaft or drywall. Staining points to a flashing failure that patching rarely fixes for long.
Repair, replace the dome, or replace the whole unit?
Match the fix to what actually failed. A cracked dome on a curb-mounted skylight can be swapped while the curb and flashing stay, a fogged insulated pane means a new sash or unit, and a leak at the flashing is a reflash job. VELUX notes that its Fresh Air skylights made after April 1996 need the whole operating sash replaced with the glass. The table pairs each failure with the fix and the published price for it.
| If this failed | Right fix | Published cost | Source |
|---|---|---|---|
| Cracked or hazed acrylic dome, curb intact | Replace the dome only | $350 to $900 | HomeGuide, Feb 2026 |
| Cracked glass pane, frame sound | Replace the glass or sash | $150 to $600; $300 to $800 | HomeGuide; VELUX |
| Fogged glass (failed insulated seal) | Replace the sash or the full skylight | $800 to $2,400 for a full unit | HomeGuide, Feb 2026 |
| Leak at flashing, unit under 10 years old | Call the installer first: VELUX’s installation warranty runs 10 years with VELUX flashing | $150 to $500 flashing repair; $300 to $800 flashing and sealing | HomeGuide; VELUX |
| Leak plus unit over 20 years old | Full replacement, ideally at reroof | $800 to $2,400 | HomeGuide, Feb 2026 |
| Rotted curb or frame around the opening | Full replacement plus framing repair | Unit cost plus $150 to $600 frame repair | HomeGuide; VELUX lists $170 to $600 for framing |
| You no longer want the skylight | Remove it and roof over the opening | $350 to $1,000 | HomeGuide, Feb 2026 |
If the frame is sound and only the dome is damaged, the dome-only route at $350 to $900 is the cheapest full fix on HomeGuide’s figures. For dome materials and the steps involved in replacing a plastic bubble skylight, see our plastic skylights guide. When a leak keeps coming back, the problem is almost always the flashing or the sealed unit, and more caulk will not solve it: VELUX designs its flashing kits to shed water “without relying on sealants that can break down over time” (2025 catalog). For diagnosing exactly where water is entering first, see our guide to skylight leak sources and repair.
How much does roof skylight replacement cost?
Roof skylight replacement costs $800 to $2,400 on average per HomeGuide (February 2026) and $800 to $2,200 per VELUX, covering the new unit, a flashing kit and labor. HomeGuide puts the job at 3 to 5 hours and adds $100 to $500 where a permit is required. No federal credit offsets a 2026 install: the 25C credit, which covered ENERGY STAR Most Efficient skylights up to $600, does not apply to property placed in service after December 31, 2025, and the 25D credit ends for expenditures made after that date, both under Public Law 119-21 per the IRS FAQ on Public Law 119-21. Some 2026 cost guides, including HomeGuide’s, still mention a 26% to 30% federal credit for skylights; that statement is out of date for 2026 work.
| Cost line | Published range | Source |
|---|---|---|
| Full skylight replacement | $800 to $2,400 | HomeGuide, Feb 2026 |
| Full skylight replacement | $800 to $2,200 | VELUX |
| New skylight where none existed | $1,600 to $4,200 | HomeGuide, Feb 2026 |
| Dome replacement | $350 to $900 | HomeGuide, Feb 2026 |
| Glass replacement | $150 to $600 (HomeGuide); $300 to $800 (VELUX) | HomeGuide; VELUX |
| Flashing and sealing repair | $300 to $800 | VELUX |
| Motor, electric or solar Fresh Air skylight | $110 to $510 (VELUX); $350 to $700 (HomeGuide) | VELUX; HomeGuide |
| Sun Tunnel tubular skylight repair | $300 to $500, replaced in half a day or less | VELUX |
| Permit, where required | $100 to $500 | HomeGuide, Feb 2026 |
| Remove skylight and roof over | $350 to $1,000 | HomeGuide, Feb 2026 |
Worked example: replacing two skylights at HomeGuide’s $800 to $2,400 each comes to $1,600 to $4,800, and a $100 to $500 permit brings the total to $1,700 to $5,300. HomeGuide notes that skylight labor costs less during a reroof than as a standalone job, because on its own the roofer has to tear back and re-lay the surrounding shingles just for that one unit. For a full breakdown by brand and size, see our skylight replacement cost guide. Upgrading to a modern low-E glazing at the same time is covered in energy efficient skylights.
Curb-mounted vs deck-mounted replacement
The mount type decides how disruptive the replacement is. A curb-mounted skylight sits on a raised wood curb, so you can lift off the old unit and drop in a new one without disturbing the shingles. A deck-mounted skylight is nailed directly to the roof deck and integrates its flashing under the surrounding shingles, so replacing it means tearing back and re-laying those courses. VELUX’s 2025 catalog rates its deck-mounted units for 14 to 85 degrees (3:12 to 137:12) and its curb-mounted units for 0 to 60 degrees (0:12 to 20:12), and calls curb mounts ideal for replacing existing skylights.
| Factor | Curb-mounted | Deck-mounted |
|---|---|---|
| Profile | Raised on a wood curb; at least 4 inches above the roof below 3:12 (IRC R308.6.8) | Low, nailed directly to the roof deck |
| Roof slope (VELUX 2025 catalog) | 0:12 to 20:12 (0 to 60 degrees) | 3:12 to 137:12 (14 to 85 degrees) |
| VELUX flashing system | Pre-attached gasket, adhesive underlayment, engineered flashing | Pre-attached deck seal, adhesive underlayment, engineered flashing |
| Replacement disruption | Low, reuse the curb, no shingle tear-back | Higher, shingles must be lifted around the unit |
| Who does it | Handy owner or roofer | Roofer, tied into the shingle field |
If your existing skylight is curb-mounted and the curb is solid, you can often reuse it and only replace the unit on top, which is why curb mounts suit repeat replacements and low-slope roofs. For ordering, VELUX asks for the width and length measured along the side where the shingles meet the flashing, plus the height of the skylight or curb. A rotted or soft curb changes the job into a full replacement with framing repair.
Why replace a skylight during a reroof
Replace a skylight during a reroof because the flashing labor is already priced into the job. A skylight is waterproofed by a flashing kit that tucks under the surrounding shingles, so reflashing always requires those shingles to be off. During a reroof they are already removed, so the added cost is the new unit and the kit, not a separate tear-back. VELUX says syncing both projects “allows the warranties to be coordinated.” For a fuller replace-or-keep checklist, see our guide on whether to replace skylights when reroofing.
| If | Then |
|---|---|
| You are reroofing and the skylight is 15 or more years old, fogged or leaking | Replace the unit and its flashing kit with the roof |
| You are reroofing and the skylight is under 10 years old and clear | Ask the maker in writing whether the warranty survives a reinstall; HomeGuide notes reusing old skylights in a new roof typically voids the skylight warranty |
| The roof has 10 or more years left and the skylight leaks | Standalone reflash or replacement now |
| The roof is due for replacement within about 5 years and the skylight is dry | Wait and do both in one job |
| The roof slope is below 3:12 | Curb-mounted unit on a curb at least 4 inches tall (IRC R308.6.8) |
Timing also aligns the warranties. Manufacturer no-leak installation warranties, such as the 10-year coverage on VELUX units, generally apply only when the matching manufacturer flashing kit is installed to spec; the VELUX Limited Warranty (XUS 20194) limits its no-leak promise to the original installation, on one layer of properly installed roofing, installed strictly to VELUX instructions. Replacing the skylight and reflashing at the same time as the roof puts the skylight warranty and the roof warranty on the same clock and the same watertight layer.
A skylight bought at a 2010s reroof will often reach HomeGuide’s 15 to 40 year replacement window at about the same time as the shingles around it. If your unit is 15-plus years old and you are reroofing, replacing it now avoids a roofer returning within a year or two to open a fresh roof around an aging skylight. Our roofing material lifespan report shows how skylight and roof service lives line up.
The roof skylight replacement process, step by step
A professional roof skylight replacement on a pitched, deck-mounted unit follows the sequence below, which keeps the opening watertight from the deck up. Each flashing piece has to lap over the one below it, shedding water the way shingles do, and HomeGuide puts the whole job at 3 to 5 hours for an average replacement.
- Measure and order. Record the width and length along the side where the shingles meet the flashing and the height of the skylight or curb, the measurements VELUX asks for, and order the matching flashing kit for your roofing material.
- Remove shingles around the skylight. Lift and set aside the courses above and beside the opening to expose the old flashing.
- Detach the old flashing and unit. Pull the head, side, and sill flashing, then unfasten and lift out the old skylight.
- Inspect and repair the deck and curb. Replace rotted decking or curb framing and confirm the rough opening matches the new unit. On a slope below 3:12, the curb must stand at least 4 inches above the roof plane unless the maker’s instructions say otherwise (IRC R308.6.8).
- Set the new skylight and underlayment. Fasten the new unit to the deck or curb. VELUX deck-mounted kits include a pre-attached deck seal and adhesive underlayment that runs up the sides and head.
- Install the manufacturer flashing kit. Fit the sill, step, and head flashing in order so each piece laps over the one below.
- Reshingle and seal. Weave the surrounding shingles back over the side and head flashing, leaving the sill flashing exposed to drain.
Can you replace a roof skylight yourself?
A handy homeowner can replace a curb-mounted dome, but a deck-mounted skylight replacement is a roofer’s job. Dome swaps reuse the existing flashing and curb, so the risk is low. A deck-mounted unit ties into the shingle field and depends on flashing installed in the correct order, and a mistake there leaks straight into the ceiling. HomeGuide also names roofers as the most qualified contractors for skylight work and lists $150 to $300 minimum call-out fees for roof work.
Two practical limits push the deck-mounted job to a contractor. First, the leak coverage depends on how the flashing goes in, not on who installs it. VELUX says its 10-year installation warranty applies “no matter who installs the skylight” (VELUX professional warranty page), but only for VELUX skylights with VELUX flashing installed strictly to its instructions, so a flashing mistake can cost the coverage whoever makes it. Second, comparing a repair against a full replacement is the same decision homeowners face across the roof, covered in roof repair vs replacement. If the surrounding roof is near end of life, replacing the skylight alone rarely makes sense.
Hiring a contractor for this? If you would rather have a roofer handle roof skylight replacement, choose one whose record you can check. The Roofing Brief ranks manufacturer-certified roofers in 350 U.S. metros and checks each leader against licence and BBB records, including New York, Los Angeles, Chicago, Dallas, Houston, Miami, Washington, Atlanta, Philadelphia, Phoenix, Boston, Riverside. Find your area in the full index of metro roofer rankings.
Frequently asked questions
How much does it cost to replace a roof skylight?
Replacing a roof skylight costs $800 to $2,400 on average per HomeGuide (February 2026) and $800 to $2,200 per VELUX, including the unit, flashing kit and labor. Replacing only a cracked dome on a curb-mounted unit runs $350 to $900, and a permit adds $100 to $500 where required. No federal tax credit applies to a 2026 install under Public Law 119-21.
Should I replace my skylight when I get a new roof?
Yes, in most cases. Replacing a skylight during a reroof means the surrounding shingles are already off, so you pay for one flashing job instead of two, and VELUX says syncing the projects lets the warranties be coordinated. HomeGuide notes that reusing old skylights in a new roof typically voids the skylight warranty. If your skylight is over 15 years old, replace it at the reroof.
Can you replace just the glass or dome in a skylight?
Sometimes. On a curb-mounted skylight with a cracked or hazed acrylic dome and a sound curb, a dome replacement runs $350 to $900 per HomeGuide and reuses the flashing. Glass replacement runs $150 to $600 per HomeGuide or $300 to $800 per VELUX. If the insulated glass has fogged, the seal has failed, and on VELUX Fresh Air units made after April 1996 the whole sash is replaced with the glass.
How long do roof skylights last?
HomeGuide gives skylights a 15 to 40 year replacement interval, and VELUX says its units often last 30 years or longer. VELUX warranties glass seal failure for 20 years and installation for 10 years when installed with VELUX flashing. Poor original installation can cut the life to a few years, which makes correct flashing the main factor in how long a skylight lasts.
Do you need a roofer to replace a skylight?
A deck-mounted skylight replacement should be done by a roofer because it ties into the shingle field and depends on flashing installed in the correct order. A curb-mounted dome swap reuses the existing curb and flashing and is within reach of a handy homeowner. VELUX says its 10-year installation warranty applies no matter who installs the skylight, but only with VELUX flashing installed strictly to its instructions.
Is it worth replacing an old skylight?
Replacing an old skylight is usually worth it when the unit is over 20 years old, fogs between the panes, or leaks repeatedly. The 2021 IECC caps skylight U-factor at 0.55 in climate zones 3 to 8 for new homes, a benchmark older single-pane units do not meet. The strongest case is replacing it during a reroof, when the flashing labor is already priced in.
Shopping for a like-for-like swap? Our guide to the best replacement skylights and brands covers the models worth buying.