Skylight Installation in Mill Valley, CA

What Skylight Installation Actually Involves

A skylight is a glazed opening set into your roof to bring daylight into a hallway, bathroom, or stairwell with no good wall for a window. Installation means cutting through the shingle, underlayment, and roof deck, then framing a watertight curb around the opening.

That curb is where the job lives or dies. Water travels sideways under shingles, so a unit needs step flashing woven into each field course and counter-flashing sealed against the curb. Skip either and you get a leak that stains the ceiling months later.

On a typical home we cut the opening between two rafters, add blocking, and leave the truss and ridge beam untouched. About one roofing square of shingles gets disturbed, and the roofline has to be relaid so the finished roof still looks original.

Fixed skylights, vented skylights, sun tunnels, and solar-powered blinds

• Fixed skylights don't open, which makes them the least likely to leak and the simplest way to light a stairwell.
• Vented skylights crank or motor open and pull hot air out of a loft, working with a ridge vent to move air through the attic.
• Sun tunnels use a small rooftop dome and a reflective tube to push daylight down to a windowless hall for a fraction of the cost.
• Solar-powered blinds run off a panel on the glass, so you can dim a west-facing unit without wiring through the insulation.

We install VELUX and Solatube units because both publish flashing kits built for a specific curb and roof pitch. That matters more than the glass. A good unit with bad flashing leaks; a mid-grade unit with correct flashing usually doesn't.

Roof Systems We Work With

A skylight installation is a roofing job first and a daylighting job second. Whatever covers your roof has to be reopened, matched, and resealed, and we handle all of these systems.

• Asphalt shingle roofs — three-tab shingle and architectural shingle get new field course pieces cut and woven around the curb.
• Wood shake and cedar shake need hand-split pieces and a wider flashing apron because the material is thicker at the butt.
• Slate, clay tile, and concrete tile take a torch-applied membrane plus copper flashing and a tile hook layout that ties into the surrounding coursing.
• Metal panel roofing — standing-seam panel and corrugated panel — uses a factory curb and a gasketed boot instead of shingle flashing.
• Low-slope sections get a membrane detail: TPO, EPDM, or PVC membrane over a built-up roof or modified bitumen curb.

Under the surface we're thinking about layers nobody sees: roofing felt, tar paper, synthetic underlayment, and ice-and-water shield. Old bitumen, tar, and asphalt felt usually come up with the old unit, and we lay a fresh self-adhered sheet a full course past the curb.

What Skylight Installation Costs

Pricing depends on how much roof has to come apart and what has to be rebuilt underneath it. Here is what moves the number.

• Unit type and size — a fixed skylight costs far less than a vented unit with motorized or solar-powered blinds.
• Roof covering — shingle reopens quickly; slate, clay tile, and cedar shake take more labor and matching material.
• Decking condition — rot in the sheathing, plywood, or OSB gets replaced before the new curb goes on, not after.
• Interior finish — drywall, paint, and trim around the opening are separate line items on your roof estimate.
• Permits and inspection — building code requires a permit, and the fee is set by valuation.
• Flashing upgrades — copper or lead and a custom curb cost more and outlast the roof.

Signs You Need Skylight Repair or Replacement

Most of these show up long before water reaches the drywall. Catching them early is the difference between a flashing repair and a full interior repair.

• Water rings or dark streaks on the ceiling mean the sealant or counter-flashing has failed.
• Condensation on the inner pane points to a broken thermal seal or a missing vapor barrier.
• Cracked caulk or peeling mastic around the curb lets water wick into the sheathing.
• Daylight visible around the frame from inside the attic means flashing pulled loose in a wind event.
• Granule loss and curling shingles just upslope of the unit — that is where an ice dam forms and pushes water sideways.
• A foggy pane, rattling glass, or a crank that will not close is end-of-life wear.
• Sag or droop in the surrounding roofline usually means framing has settled around the opening.

Our Step-by-Step Skylight Installation Process

Most shingle-roof installs finish in a single day. Tile, slate, and cedar shake take longer because the covering has to be carefully lifted and reset.

1. Roof inspection first — we check decking, rafter bays, and any existing chimney flashing, pipe flashing, pipe boot, or boot flashing before anyone cuts.
2. Design consultation and layout — we confirm unit size, the room below, and roof pitch, then pull the permit.
3. Tear-off around the opening — a pry bar and roofing shovel lift two courses on the uphill side, and a dumpster takes the debris.
4. Framing and deck work — blocking goes between rafters or joists, rotted sheathing comes out, and the curb is set square to ridge and eave.
5. Flashing and weatherproofing — step flashing is woven in course by course, counter-flashing caps the curb, and ice-and-water shield runs up the valley side. Adhesive and sealant are backup, never the system.
6. Roofing back in — fresh felt and synthetic underlayment, then shingles or panels relaid to match courses and the ridge cap, fixed with ring-shank nails and screws set by nail gun and air compressor.
7. Interior finish and cleanup — insulation packed around the shaft, drywall patched, and a magnet run over the lawn for nails.

Roof Details That Decide Whether It Stays Dry

A skylight never sits alone up there. It sits in a neighborhood of details, and any one of them can send water toward your curb instead of away from it.

• Drip edge along the eave and rake keeps runoff from curling back under the shingle edge.
• Gutter and downspout condition matters, because a clogged gutter backs water up under the eave and into the fascia.
• Ridge vent and soffit vent work together to dry the attic; blocked soffit ventilation pushes moisture into the sheathing.
• Hip, gable, dormer, and parapet walls each need their own flashing, and apron flashing at a sidewall is a common leak point.
• Valleys and the chimney are where water concentrates, so we look at both during the same roof inspection.
• A mansard, gambrel, or steep gable changes how we anchor, so scaffold, ladder, and safety harness go up first.
• An awning, canopy, or deep overhang can shade the room you are trying to brighten, which changes the unit we recommend.
• Purlin, batten, and counterbatten framing on older and tile roofs change how the curb gets blocked.
• On low-slope work, a scupper, roof drain, and coping along a parapet edge have to shed past the new curb.
• An attic fan or old coating mounted near the opening gets moved or patched on the same visit.

Local Climate, Permits, and Warranty

Coastal fog and morning moisture sit on Marin roofs for weeks, then winter atmospheric rivers drop heavy rain on the same curb detail the fog has been softening all summer. Skylights fail here from wet-weather flashing more than from glass.

Mild temperatures and low snowfall risk mean we rarely fit a snow guard here. We still build the curb so nothing ponds, because roof pitch, exposure, and the direction a dormer faces change how much water that detail sees.

Daylighting also cuts your electric lighting load, and a tight curb plus working attic ventilation keeps heat gain down. If a storm tears flashing loose, we handle the repair and help document the damage for insurance claims.

Mill Valley Roofing is a licensed & insured roofing contractor, so the work is permitted, inspected, and built to code. Warranty terms go into your roof estimate in writing before anything is ordered, and a roofer walks the finished roof with you.

Frequently Asked Questions

How long does skylight installation take?

Skylight installation usually takes one day on asphalt shingle, and two to three days when slate, clay tile, or cedar shake has to be lifted and reset. Interior drywall and paint often happen on a later visit.

Will a new skylight leak?

A skylight leaks when its flashing fails, not because the idea is unsound. Step flashing, counter-flashing, and a properly sealed curb keep water out through fog and winter storms.

Does skylight installation need a permit?

Skylight installation needs a permit under building code because it changes the roof structure. We pull it, schedule the inspection, and keep the paperwork in your file.

Can a skylight go on a flat roof?

Yes. Low-slope skylight installation uses a raised curb and a membrane detail rather than shingles, and we set TPO, EPDM, or PVC membrane around the base so the opening stays waterproof.