Gutters, Skylights & Exteriors
Skylight installation and replacement in San Jose
A skylight is a hole in the roof that has to stay dry for thirty years. The glass is the easy part; the framing, the curb and the flashing are what decide whether it leaks.
What we treat
- Concrete and clay tile
- Composition shingle
- Flat, torch-down and TPO
- Spray foam
- Standing seam metal
Quick answer. Skylight installation in San Jose cuts and frames an opening between the rafters, builds or sets a curb, installs the unit with a manufacturer flashing kit, and finishes the light shaft inside. Replacing an old dome on an existing curb takes a few hours; a new cut-in with a finished shaft usually takes one to two days.
Updated September 2026
The job
Where skylights go wrong and how we avoid it
Most skylight leaks come from the flashing, not the glass: a curb sealed with mastic instead of stepped flashing, or a unit set too low on a flat roof where water ponds against it. We use the manufacturer's flashing kit for the roof type and raise curbs on low slopes.
The best time to replace an old skylight is during a re-roof, when the flashing can be integrated with new underlayment instead of patched into an old roof.
Your options
Fixed skylight, venting skylight or sun tunnel?
It depends on the room and whether you want air as well as light.
| Question | Fixed | Venting | Sun tunnel |
|---|---|---|---|
| Gives | Light and a view of sky | Light, view and airflow | Light only |
| Best rooms | Living areas, stairs | Kitchens, baths | Halls, closets |
| Framing | Opening and shaft | Opening and shaft | Fits between rafters |
| Relative cost | Middle | Highest | Lowest |
Jobs this page covers
New skylight cut-in
A new skylight starts in the attic, where we find the rafters and plan the opening so as few as possible are cut. Cut rafters get headers and doubled members on each side. The deck opening is cut, a curb built or the unit's own frame set, and underlayment and step flashing lapped around it in the order water will run. The unit is set square and level so the sash closes and the flashing laps correctly. Inside, the light shaft is framed, drywalled and finished, ready for paint.
Skylight replacement during a re-roof
Old acrylic domes yellow and crack, and their flashing is usually the weakest point in a roof being replaced. With the roof already open, we remove the old unit, check the curb for rot, and set a new glass skylight with its flashing woven into the new underlayment. It costs less than replacing it later, and it avoids cutting into a brand new roof to fix an old skylight. Where the old opening is an odd size, we reframe it to a standard unit so future replacements are simple.
Sun tunnels
A tubular skylight brings daylight into a hallway, bathroom or closet without a full shaft. The dome sits on a low flashing on the roof, a reflective tube runs through the attic, and a diffuser mounts in the ceiling. It fits between rafters without cutting framing and installs in a few hours. It gives light, not a view, which is the trade-off to weigh against a full skylight. Ten and fourteen inch tubes cover most hallways; longer runs lose some light at every bend.
Venting skylights
A venting skylight opens to let hot air out, which is useful in kitchens and bathrooms and in rooms that heat up in summer. Manual units open with a crank pole; solar and electric units run on a remote and close on their own when a rain sensor gets wet. We wire electric units to a nearby circuit or use solar models where running power to the ceiling is impractical. Screens and blinds are ordered with the unit so they fit without extra trim.
Cost
What a skylight project costs depends on
Skylights are priced by the unit, the framing and the finish inside.
- Unit type Fixed, manual venting and solar venting units differ widely.
- New cut or replacement New openings need framing and a shaft.
- Shaft finish Drywall, tape and paint add to a new cut-in.
- Roof type Tile and flat roofs need different flashing and curbs.
- Electrical Powered units need a circuit unless solar.
- Timing During a re-roof is cheaper than cutting into a finished roof.
What we see on San Jose roofs
San Jose gets something like 3,400 hours of sun a year, so glazing choice matters more here than the skylight's size: low-e glass and a venting unit keep a room from overheating in August. On the flat and nearly flat post-and-beam roofs of the Willow Glen Eichler tracts, the curb height matters as much as the glass, because a low curb on a roof with that little pitch sits in standing water every storm.
Scope
What a new skylight includes
The full scope of a new cut-in, so nothing is left for another trade.
- Attic layout and rafter check
- Headers and framing around the opening
- Curb or unit frame set to the roof slope
- Manufacturer flashing kit and underlayment laps
- Glazing chosen for the room's sun exposure
- Light shaft framed and drywalled
- Hose test of the finished flashing
What happens after you call
How a skylight install runs
- 1
Plan from the attic
Rafters located, opening sized to them.
- 2
Choose the unit
Fixed, venting or tube, glazing matched to the room.
- 3
Frame and cut
Headers set, deck opened.
- 4
Curb and flash
Manufacturer kit, lapped with the underlayment.
- 5
Finish inside
Shaft framed, drywalled and ready for paint.
- 6
Water test
Hose test on the flashing before we leave.
FAQ
Questions we get asked
Not when it is framed, curbed and flashed to the manufacturer's kit. Most leaks come from shortcuts at the flashing.
Yes, on a raised curb so it sits above any standing water.
A new opening that cuts framing is structural work and is permitted. We handle it.
The glass unit commonly lasts twenty years or more; the flashing lasts as long as the roof around it.
If it is more than fifteen years old or plastic, yes; it is far cheaper than doing it later.
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Learn morePlan a skylight that stays dry
Tell us the room and the roof type. We plan the opening from the attic and quote the unit, framing and finish together.