If your skylights are as old as your roof, replace them together: on this single-story Pleasant Hill home we tore off a 20-year-old shingle roof, laid a new OSB deck, installed two new skylights and finished with Owens Corning shingles in Sierra Gray, under a city permit that passed final inspection.
Usually yes, if the skylights are near the end of their life: replacing them during the reroof lets the new flashing be woven into the new shingles as they go down, instead of cutting into a brand-new roof later. On this single-story Pleasant Hill home, the two original skylights sat in a roof about 20 years old, so both came out with the old shingles and two new units went in on the new deck, flashed into new Owens Corning underlayment and shingles. A homeowner on r/Roofing asked exactly this before talking to roofers: their skylights were about 25 years old and not leaking, and they wanted to know whether to replace them with the roof.
A 20-Year-Old Roof With Two Skylights and a Few Patches
This is a single-story home in Pleasant Hill with a hip roof of brown asphalt shingles about 20 years old, two skylights on the main slopes, and a small shed in the backyard. The homeowner called us in mid-June, was collecting bids, and wanted the whole roof replaced. On the inspection the shingles showed their age: faded and uneven color, worn granules, and more than one spot where earlier repairs had been patched in. The two skylights had been in the roof as long as the shingles around them, which is the question every reroof with skylights comes down to.
Tear-Off, New Deck Layer, New Skylights, New Shingles
A skylight’s weak point is its flashing, the metal and membrane that tie it into the roof around it, plus the seals in the unit itself, and both age on roughly the same clock as the shingles. Keeping 20-year-old skylights in a brand-new roof means either re-flashing an old unit into new shingles or coming back in a few years to cut the new roof open. So the plan was a full tear-off, two new skylights set on the new deck, Owens Corning ProArmor synthetic underlayment, Owens Corning WeatherLock self-adhered membrane, and new Owens Corning architectural shingles in Sierra Gray. The homeowner also approved a full OSB overlay so the new roof would be fastened into one continuous, sound surface. Gutters, leaf guards and downspouts were part of the same job.
Permit, Tear-Off, Re-Deck, Skylights, Shingles
We applied for the City of Pleasant Hill permit as soon as the contract was signed, and it was issued a couple of days later. The crew started at the end of June: the old shingles and both skylights came off together, down to the original deck, and new OSB went down over it with new pipe flashings set through the new sheathing.
The new skylights went onto the new deck before the shingles, so their flashing kits could be layered into the underlayment and then into each course of shingles as the roof went up, which is the clean tie-in the Reddit thread is asking about. The shingles went on over the whole house, and the backyard shed got the same Sierra Gray shingles so the two match. The job closed out with the city’s final inspection in early July, and the inspector confirmed the permit was finaled.
Before vs. After
| Feature | Before | After |
|---|---|---|
| Roof age | About 20 years, with patch repairs | Brand new roof system |
| Skylights | Two original units, original flashing | Two new skylights, flashed into the new roof |
| Deck | Original sheathing | New OSB overlay over the original deck |
| Underlayment | Original felt | Owens Corning ProArmor synthetic underlayment |
| Shingles | Worn brown asphalt | New Owens Corning architectural shingles, Sierra Gray |
| Paper trail | None | City permit and passed final inspection |
Why Skylights and Reroofs Belong Together in Pleasant Hill
Pleasant Hill is full of single-story homes from the same building years, many with skylights that went in with the original roof or the first replacement. Summer heat in central Contra Costa County is hard on shingles and on the seals and flashing around skylights alike, so the two tend to wear out together. If your roof is due and your skylights are 15 to 20 years old or more, pricing them into the reroof costs less than paying to open a new roof later. For more work across the county, see our Contra Costa roofing page, our roof replacement service, and the El Sobrante tear-off, another reroof where the new roof went onto a new OSB layer.
“The roof over our garage had aged much faster than the rest of the house because it gets direct afternoon sun. We ended up replacing that section along with the main roof, and everything blends together perfectly.”— Sherlyn Z., via Google
Skylights & Reroofs — FAQs
Can skylights be replaced later, after the new roof is on?
They can, but it costs more roof. Replacing a skylight later means removing and re-flashing shingles around it on a roof that is otherwise new, and the tie-in is never as clean as one built in while the courses go down. If a skylight is 15 to 20 years old or more, the reroof is the cheapest time to replace it.
What is a plywood or OSB overlay on a reroof?
It is a new layer of sheathing fastened over the existing roof deck after the old shingles come off, so the new roof is nailed into one continuous, sound surface. On this Pleasant Hill home the homeowner approved a full OSB overlay over the original deck before any underlayment went down.
Do you need a permit to replace a roof in Pleasant Hill?
Yes. This job ran under a City of Pleasant Hill building permit that we pulled before work started, and it closed out with a final inspection from the city. We handle the application and the inspections as part of the job.
Is Your Roof Due, Skylights and All?
We will inspect the roof and the skylights, tell you which ones are worth keeping, and handle the permit. See more finished work on our roofing projects page.
Gina K. writes about Bay Area roofing for Lifetime Roofing & Renovation, drawing on the team's 16+ years of experience roofing homes across Silicon Valley.
