Two Marin roofs, one winter. In Corte Madera, a home on Tamalpais Drive carrying 24 solar panels got a full tear-off, a new plywood deck, CertainTeed Presidential shingles and 212 feet of new gutters — $41,500 all in. In Mill Valley, a house and its backyard studio on Meadow Drive, arrived at us under an emergency tarp, got new decking, double underlayment on the low-slope sections and a new architectural shingle roof — $25,772. Here is what each one involved and why they cost what they did.
What Does a Roof Replacement Cost in Marin County?
These two Marin County roof replacements cost $41,500 and $25,772. The Corte Madera project — $41,500 all in — included detaching and resetting 24 solar panels, a complete tear-off, a $10,000 change order for a full plywood deck overlay with ice-and-water shield across the whole roof, CertainTeed Presidential shingles in a Title 24 cool-roof rated color, and 212 linear feet of new gutters and downspouts. The Mill Valley project — $25,772 — covered the main house and a detached backyard studio: tear-off, new plywood decking where the old deck had failed, a double layer of underlayment on the low-slope sections that fall under a 3:12 pitch, new flashings and a new architectural shingle roof on both structures. The gap between the two numbers is almost entirely explained by three things: solar panels, a premium designer shingle, and gutters. Take those away and the two roofs were priced within a few thousand dollars of each other.
A Solar Roof on Tamalpais Drive, Rebuilt From the Deck Up
Sal’s home sits on Tamalpais Drive in Corte Madera, a few blocks off the marsh, with a 24-panel solar array across its south slopes. The shingles under and around that array were at the end of their life — granules gone, edges curling, and the kind of dark staining that means water has been sitting rather than shedding. Solar arrays hide roof problems and make them worse: shade keeps the shingles damp, and nobody can see the deck under the panels from the ground. Our December inspection told us the roof needed to go; tear-off in January told us the deck did too. Rather than patch the soft spots one sheet at a time, Sal approved a $10,000 change order for a full plywood overlay across the entire roof with ice-and-water shield over the whole deck — a belt-and-suspenders membrane that most Marin roofs never get, and exactly what a home this close to the bay, in the wind and horizontal rain the marsh delivers, should have. The array came off before tear-off and went back on new flashed mounts once the shingles were down.
The finish is CertainTeed Presidential — a thick, sculpted designer shingle that reads like wood shake from the street — in a color rated for California’s Title 24 cool-roof standard, which keeps the roof cooler in summer without giving up the shake look. New gutters and downspouts went in all the way around, 212 linear feet, sized for the way Marin storms arrive. Inspection was December 11; the deck went on in mid-January; the finished roof with the array reinstalled was photographed on February 3.
A House and a Backyard Studio on Meadow Drive, Under a Tarp
Kristine’s property on Meadow Drive in Mill Valley came to us the way a lot of Marin roofs do in winter: under an emergency tarp. The main house had a low-slope section around a skylight that had begun leaking in earnest, and the roof around it was a mix of moss, redwood and bay-tree litter packed into the valleys, and shingles worn smooth. Behind the house sits a detached backyard studio with its own small roof in the same condition. The scope covered both structures together: a full tear-off, new plywood decking where the old deck had softened, and — the detail that matters most on this house — a double layer of underlayment across every section that runs flatter than a 3:12 pitch. Low-slope shingle roofs are where Marin’s wind-driven rain gets in; doubling the underlayment there is what the shingle manufacturers require for a valid warranty below 4:12 and what a leaky skylight section actually needs. New flashings, new vents, new skylight flashing and a new architectural shingle roof finished both buildings. If your roof is leaking now, our emergency tarping service is the first call; the replacement follows once the weather allows.
Two Marin Roofs, Side by Side
| Feature | Corte Madera · Tamalpais Dr | Mill Valley · Meadow Dr |
|---|---|---|
| Scope | Main house, 24 solar panels detached and reset | Main house plus detached backyard studio |
| Deck | Full plywood overlay, ice-and-water shield over the entire roof ($10,000 change order) | New plywood where the old deck had failed |
| Underlayment | Ice-and-water shield, full coverage | Double layer on every section under 3:12 pitch |
| Shingle | CertainTeed Presidential, Title 24 cool-roof color | Architectural shingle, light gray |
| Gutters | 212 linear feet new, with downspouts | Existing retained |
| Started under | Aging shingles, hidden damage under the array | An emergency tarp over a leaking skylight section |
| Cost | $41,500 all in | $25,772 all in |
Both roofs were finished during the wet season, which is when Marin homeowners most often discover they need one. Corte Madera ran from a December inspection to a February completion with the solar detach and reset built into the schedule; Mill Valley went from tarp to finished roof on both structures without a second leak.
What This Means for Marin County Homeowners
Marin roofs live a harder life than roofs twenty miles south. Corte Madera, Mill Valley, Larkspur, San Rafael and Novato all sit in the path of wind-driven Pacific storms, under redwood, bay and oak canopies that drop litter year-round, and in a fog belt that keeps shaded slopes damp for weeks. Three lessons from these two jobs travel to every home in the county. First, low-slope sections and valleys are where Marin roofs fail — insist on double underlayment or ice-and-water shield there, not just at the eaves. Second, if you have solar, plan the roof and the array together; the shingles under the panels are the worst on the house, and the panels have to come off to fix them (our Castro Valley solar reroof walks through that process in detail). Third, a leak under a tarp is a sign to replace, not to patch — the tarp buys weeks, the roof buys decades. We serve the whole county from our Marin County roofing page, with the same crews that did these two.
Marin County Roof Replacement — FAQs
Why did the Corte Madera roof cost more than the Mill Valley roof?
Three things: 24 solar panels that had to be detached and reset, a premium CertainTeed Presidential designer shingle instead of a standard architectural shingle, and 212 linear feet of new gutters and downspouts. The $10,000 change order for a full plywood overlay with ice-and-water shield also added to the total. Without those items the two roofs would have been priced within a few thousand dollars of each other.
What is double underlayment and when is it required?
Double underlayment means two overlapping layers of roofing underlayment under the shingles instead of one. Shingle manufacturers require it on slopes between 2:12 and 4:12 for a valid installation and warranty, because water moves slowly on low-slope roofs and wind can drive it under the shingle edges. On the Mill Valley project every section flatter than 3:12 got two layers, including the skylight section that had been leaking.
Do you have to remove solar panels to replace a roof in Marin?
Yes. The shingles under a solar array cannot be replaced with the panels in place, and they are usually the most deteriorated shingles on the roof. On the Corte Madera project all 24 panels came off before tear-off and were reinstalled on new flashed mounts after the new roof was complete, as one scheduled part of the job.
Can you replace the roof on a detached studio or ADU at the same time?
Yes, and it is usually the most economical way to do it, because the crew, dumpster and permit are already on site. The Mill Valley project covered the main house and the backyard studio together for $25,772, with both roofed in the same shingle so they match.
How much does a roof replacement cost in Marin County?
These two projects came to $41,500 for a Corte Madera home with solar, a premium shingle, a full deck overlay and new gutters, and $25,772 for a Mill Valley house plus a detached studio with new decking and double underlayment. Your number depends on roof size, pitch, decking condition, solar, gutters and the shingle you choose; see our Bay Area roof replacement cost guide for current ranges.
Need a Roof Replaced in Marin County?
Solar or no solar, house or house-plus-studio, tarp or not yet — we’ll inspect it and give you a real number. See more of our work in the project gallery, or book a free inspection today.
Gina K. writes about Bay Area roofing for Lifetime Roofing & Renovation, drawing on the team's 16+ years of experience and 1,000+ completed roofs across Silicon Valley.
