Replace the skylight when you replace the roof if it is old, fogged, leaking or damaged. The shingles are already off, the flashing is already being redone, and the swap costs less than it will later. Keep it only if it is fairly new, in good shape and meets your efficiency goals.
This guide shows how to decide, what it costs, how the work is done and what to check before the crew starts.
TL;DR
- Replace a skylight that is old, fogged, leaking or damaged during the roof job. Keep one that is relatively new and performing well.
- Budget about $600 to $1,600 per unit during a roof replacement. The same swap later as a standalone job runs about $900 to $2,500.
- The flashing matters more than the glass. Ask for new flashing on every skylight, kept or replaced.
- Have the crew inspect the framing and sheathing around the opening before the new unit goes in.
- Ask your roofer to list each skylight as its own line in the written estimate.
Table of Contents
- Should you replace the skylight when replacing the roof?
- What skylight replacement costs during a roof job
- How the skylight is replaced during a roof replacement
- Efficiency ratings to check
- Questions to settle before the crew arrives
- Winter and timing
- If a new roof leaks at the skylight
- Storm damage and insurance
- Our perspective
- Get the skylight priced with your roof
- FAQ
- Sources
Should you replace the skylight when replacing the roof?
Use condition and age to decide. The U.S. Department of Energy's Building America guidance says to keep a skylight that is in good shape, relatively new and meets performance goals for heat loss, air loss and solar heat gain. It says to replace one that is damaged, relatively old or short of those goals.
The Department of Energy names three problems that warrant replacing a unit:
- Failure of the insulated glass unit from long-term water exposure. You see this as condensation between the panes.
- Leaks through the joints in the frame.
- Leaks through gaskets or weather stripping on opening (operable) units.
If you see any of these, replace the unit. Do not shingle around it and hope.
Check the skylight against the roof
A new asphalt roof is built to last for decades. You can read more in our guides on asphalt shingle lifespan and how long architectural shingles last. A skylight that is already well into its life will not keep pace with that roof.
One cost calculator notes that skylight gaskets and flashing have a lifespan similar to architectural shingles, and that a skylight 12 or more years old is a poor one to keep because the roofer still charges to reflash it. If the seal fails a few years later, a crew has to open up the new shingles to swap it. Treat that as a planning rule, not a guarantee.
Quick decision guide
| What you see | Likely call |
|---|---|
| Fog or moisture between the panes | Replace |
| Stains on the ceiling or frame near the unit | Replace, and inspect the opening |
| Cracked dome or damaged frame | Replace |
| Old unit, unknown age, no efficiency label | Replace |
| Newer unit, clear glass, no leaks, dry opening | Keep, with new flashing |
What skylight replacement costs during a roof job
Plan on $600 to $1,600 per unit when the swap happens during a roof replacement. The same source puts a standalone swap later at $900 to $2,500. These are planning ranges, not a quote for your roof.
Why the gap? When the roof is already torn off, the crew does not have to open finished shingles around the unit. One calculator estimates bundling saves $350 to $750 per skylight in shingle tear-back labor.
Cost by skylight type
VELUX publishes ranges that include labor and interior and exterior finish work. These apply to replacing an existing unit, per its skylight FAQ:
| Skylight type | Replacement range |
|---|---|
| Fixed | $900 to $2,400 |
| Manual fresh-air | $1,200 to $2,700 |
| Solar-powered fresh-air | $2,000 to $3,600 |
| Electric fresh-air | $2,100 to $3,600 |
Your price moves with the unit size, the type of glass, the roof pitch, how high the roof is and how much interior finish work is needed.
What a new roof costs around it
Our published range for a full roof replacement is $7,500 to $18,000. Skylights are priced as separate lines on top of the roof. We confirm the number after an inspection. See our roof replacement services for what we install.
Replace or remove?
Some homeowners ask whether it is cheaper to remove a skylight. Removal means framing and sheathing the opening, finishing the ceiling inside and roofing over the patch. It also means losing the daylight. Ask your roofer to price both options on the same estimate. Then compare them side by side with the replacement figure.
Adding a skylight where there is none
A new skylight in an existing roof costs more than a swap, because the roofer cuts and frames a new opening. VELUX lists new-installation ranges of $2,100 to $4,600 for manual fresh-air units, with solar and electric models higher. If you want a new one, the roof replacement is the cheapest time to add it.
How the skylight is replaced during a roof replacement
The process follows the roof job. According to VELUX's replacement installation process, the steps look like this:
- Measure the existing skylight and order a unit sized to fit.
- Remove the old skylight, its flashing, the underlayment and the surrounding shingles.
- Fit the new flashing, underlayment and skylight to the existing opening.
- Attach the unit to the roof.
- Replace the surrounding shingles.
On a full roof replacement, the shingles are already off, so steps 2 and 5 fold into the main work.
Flashing is the leak point
The water-management detail is built from the bottom up. Building America describes it this way: underlayment and self-adhered flashing go around the curb or deck, sill flashing goes over the shingles, step flashing is woven with each shingle course, and head flashing goes at the top.
That order lets water run over each layer and away from the opening. If the order is wrong, water gets behind a layer. Ask your roofer to describe how they will flash each skylight. For more on what goes wrong on a new roof, read our roof installation mistakes checklist.
Inspect the opening
The same guidance says to inspect the opening for moisture damage, mold, rot or insects. Damaged framing or sheathing must be repaired before the skylight is reinstalled or replaced. Ask for a price for this repair work before the job starts. A leaking old skylight often means wet wood around it.
How long it takes
VELUX says a replacement can take as little as 30 minutes and up to 2 hours for a single unit. That is the swap itself. On a roof job, the flashing and shingle work around it add time.
Efficiency ratings to check
A replacement is a chance to improve the room. Check the label on the unit you choose.
- U-factor: how much heat passes through. Lower is better.
- SHGC: how much solar heat passes through. Lower blocks more sun.
The ENERGY STAR Most Efficient 2025 criteria for skylights call for a U-factor of 0.40 or lower in the Northern climate zone, with any SHGC. Wisconsin falls in the northern part of the country, so the U-factor is the number to compare first. Our window guide explains the same ratings: energy efficient windows in Wisconsin.
Compare labels on the exact models quoted. Do not assume every unit from a brand carries the same rating.
Questions to settle before the crew arrives
- Is each skylight listed as its own line in the estimate?
- Will every skylight get new flashing, kept or replaced?
- What is the price if the framing or sheathing is damaged?
- Which exact model and size is being ordered, and what are its ratings?
- Who handles the interior drywall and paint after the swap?
- What does the workmanship warranty cover on the skylight area?
Order the unit early. The roof date should not wait on a special-order skylight.
Winter and timing
Skylight work and roofing can be done in cold months with planning. Read our winter roof replacement checklist if your project falls outside the usual season.
If a new roof leaks at the skylight
A leak after a roof job needs fast action. Follow our same-day steps for a leaking new roof. Then call your roofer. The warranty and the documentation from the job matter here.
Storm damage and insurance
If hail or wind damaged the skylight, document it first. Take dated photos of the unit, the flashing and any interior stains. Then talk to your insurer about how your policy treats the damage, and read the policy for your deductible. Our guide explains how a roof deductible works on a claim. We also help homeowners with the claim process on hail and wind storm damage repair in Southeast Wisconsin.
Our perspective
Most skylight leaks we see are flashing problems, not glass problems. That is why we treat the skylight as part of the roof system.
When the roof comes off, every skylight gets a decision. We look at its age, its condition and the wood around it. We tell you plainly whether to keep it or replace it.
Quality installation is the priority. We believe most failures come from poor workmanship, not materials. The owner supervises the work, and we document each step so you can see what was done.
Our approach is to price the skylight as its own line, flash it new and inspect the opening before anything goes back in.
Heather
Get the skylight priced with your roof
We are a Wisconsin exterior contractor with over 25 years of owner-operated experience. We replace roofs in Dodge, Washington, Fond du Lac and Ozaukee counties and across Southeast Wisconsin. Our published range for roof replacement is $7,500 to $18,000. Ask us to include each skylight as a separate line.
See our roofing services or start at am-exteriors.com to request an inspection.
FAQ
How much does it cost to replace a skylight on a roof?
Plan on about $600 to $1,600 per unit when it is done during a roof replacement, and about $900 to $2,500 as a standalone job later. Fixed, manual and powered units fall in different ranges. Roof height, pitch and interior finish work change the final price.
Should you replace the skylight when replacing the roof?
Replace it if it is old, fogged, leaking or damaged. Keep it if it is relatively new, in good shape and meets your efficiency goals. Either way, ask for new flashing around it.
Is it cheaper to replace or remove a skylight?
It depends on the roof and the ceiling. Removal still needs framing, sheathing, roofing over the opening and interior finishing. Ask your roofer to price both on one estimate so you can compare.
How long does a skylight replacement take?
The swap of a single unit can take 30 minutes to 2 hours. During a roof replacement, the flashing and shingle work around it add to the day.
What should I check after the skylight is replaced?
Look at the ceiling and frame for stains after the first heavy rain or snowmelt. Confirm the model and ratings match your estimate. Keep the job photos and warranty papers.
Sources
- Existing Skylights Repaired or Replaced and Fully Flashed, Building America Solution Center
- Replacing Existing Skylights, Building Science Education, U.S. Department of Energy
- Skylight Replacement Cost During a Roof Replacement
- Skylight Replacement Cost Calculator
- Skylight FAQs, VELUX USA
- Replacement Installation Process, VELUX
- Residential Skylights and TDDs ENERGY STAR Most Efficient 2025 Criteria