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 swap runs about $1,250 to $3,200 installed for most homes, while replacing only a cracked dome on a curb unit can cost under $900. Skylights last roughly 20 to 30 years, and the seal or flashing usually fails before the frame does.
This guide covers when a skylight is worth replacing, how to tell a repair from a full swap, real 2026 cost ranges, curb-mounted versus deck-mounted replacement, and the step-by-step process a roofer follows.
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. This means the insulated glazing seal has failed. It cannot be resealed and the sash or unit needs replacing.
- 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. Acrylic and polycarbonate domes haze and craze after 15 to 20 years of sun exposure.
- Age past 20 years. Older units use single-pane or early double glazing with far worse insulation than a 2026 low-E unit.
- 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. If only the acrylic dome on a curb-mounted skylight is cracked, you can swap the dome and reuse the curb and flashing. If the glazing seal fogged or the flashing leaks, the sealed unit or the full skylight has to come out. Use the table below to decide before you call anyone.
| What failed | Right fix | Rough cost |
|---|---|---|
| Cracked or hazed acrylic dome, curb intact | Replace the dome only | $150 to $900 |
| Fogged glass (failed insulated seal) | Replace the sealed unit or full skylight | $900 to $2,500 |
| Leak at flashing, unit still sound | Reflash (repair) if under 15 years | $300 to $800 |
| Leak plus unit over 20 years old | Full replacement, ideally at reroof | $1,250 to $3,200 |
| Rotted curb or deck around the opening | Full replacement with framing repair | $1,800 to $4,000+ |
If the frame is sound and only the dome is damaged, the dome-only route is the cheapest path. When a leak keeps coming back, the problem is almost always the flashing or the sealed unit, and more caulk will not solve it. 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 about $1,250 to $3,200 installed for a standard fixed or vented unit, including the new skylight, a manufacturer flashing kit, underlayment, replacement shingles, and interior re-trim. Dome-only swaps on curb units cost less, and solar-powered vented units cost more before the federal tax credit. The wide range reflects unit type, roof pitch, height off the ground, and whether framing needs repair.
| Skylight type | Typical replacement cost (installed) |
|---|---|
| Dome only (curb-mounted) | $150 to $900 |
| Tubular (light tube) | $500 to $1,500 |
| Fixed (non-opening) | $900 to $2,500 |
| Vented, manual crank | $1,300 to $3,000 |
| Vented, solar or electric | $2,000 to $3,800 |
Doing the skylight on its own, separate from any roof work, adds roughly $150 to $500 in flashing and shingle labor because 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, making it a fast, lower-labor swap. A deck-mounted skylight sits low and integrates its flashing under the surrounding shingles, so replacing it means tearing back and re-laying those courses.
| Factor | Curb-mounted | Deck-mounted |
|---|---|---|
| Profile | Raised 4 to 6 inches on a wood curb | Low, sits close to the roof deck |
| Best roof slope | Low-slope and flat roofs | Pitched roofs, roughly 14 to 85 degrees |
| Replacement disruption | Low, reuse the curb, no shingle tear-back | Higher, shingles must be lifted around the unit |
| Typical labor | Half a day or less | Most of a day |
| 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. 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. Doing it separately later means paying twice for the same shingle work.
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. 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.
Skylights outlast an asphalt roof in some cases but not by much. 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 follows a set sequence that keeps the opening watertight from the deck up. The order matters because flashing has to layer correctly with the underlayment and shingles, shedding water like shingles do. Here is the process a roofer uses on a pitched, deck-mounted unit.
- 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. Check the opening for rot, replace damaged decking or curb framing, and confirm the rough opening matches the new unit.
- Set the new skylight and underlayment. Fasten the new unit to the deck or curb and run self-adhering underlayment 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. Height, roof pitch, and warranty terms push most full replacements to a pro.
Two practical limits push the deck-mounted job to a contractor. First, manufacturer no-leak warranties often require professional installation with the matched flashing kit. 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.
Frequently asked questions
How much does it cost to replace a roof skylight?
Replacing a roof skylight costs about $1,250 to $3,200 installed for a standard fixed or vented unit, including the skylight, flashing kit, underlayment, replacement shingles, and interior re-trim. Replacing only a cracked dome on a curb-mounted unit runs $150 to $900. Solar-powered vented units reach $2,000 to $3,800 before the federal tax credit. Framing repair around a rotted opening adds several hundred dollars more.
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. It also syncs the skylight and roof warranties on the same watertight layer. If your skylight is over 15 years old, replacing it at the reroof avoids a roofer reopening a fresh roof within a year or two.
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, you can replace the dome alone for $150 to $900 and reuse the flashing. If the insulated glass has fogged, the sealed unit has failed and cannot be resealed, so the sash or full unit needs replacing. A leaking flashing is a separate problem from the glazing.
How long do roof skylights last?
Roof skylights last about 20 to 30 years. The sealed glazing unit or the flashing usually fails first, often between 10 and 20 years, while the frame lasts longer. Acrylic and polycarbonate domes haze and craze after 15 to 20 years of sun exposure. 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. Manufacturer no-leak warranties often require professional installation with the matched flashing kit, which pushes most full replacements to a pro.
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, since a modern low-E unit cuts heat loss and stops the leaks. The strongest case is replacing it during a reroof, when the flashing labor is already priced in. Replacing a skylight alone on a roof near end of life rarely pays off.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.