Architect in Marin County
— Marin County
Fourteen projects in four Marin towns
Rossington Architecture is a small, full-service architectural firm located in Sausalito. We work throughout the Bay Area, focusing on San Francisco, Southern Marin and the Peninsula. Phil Rossington founded the firm in 1999.
Our portfolio includes fourteen projects in Marin County: ten in Mill Valley, two in Sausalito, one in Tiburon and one in Belvedere. Most are renovations and additions to existing houses. There is also a new house in Mill Valley, a rebuilt house in Tiburon, a garden shed, a deck trellis and a high school student center.
Certain things recur in this county. Many older Marin homes were added onto over time, usually in a rather ad-hoc way, and need a clear plan more than they need more space. Many sit on slopes, where the usable ground is limited and the view is the reason the house is there. And every town has its own way of reviewing what you propose, which we deal with below.
— Our work
Marin County projects
2025
Sarah, Mill Valley
A renovation and a series of small additions that connect a hillside house to its site and its southern views.
2023
Bay, Mill Valley
A kitchen and deck remodel of a 1960s house. A partly enclosed deck became a dining room under a shed roof that reaches toward the view.
2021
Molino, Mill Valley
A complete redo of, and addition to, an early-20th-century Sears home on a hillside with views across the valley.
2021
Tamalpais High School Student Center, Mill Valley
An interior upgrade funded by donations from local parents and built by volunteers, using reclaimed redwood from Northern California.
2020
Richardson, Mill Valley
A renovation in unincorporated Mill Valley: a simple modern white box, with a roofline addition that turned the attic into a bedroom.
2020
She Shed, Mill Valley
A 120-square-foot garden shed that houses a small music studio and a home office.
2019
Meadow, Mill Valley
A 400-square-foot front addition and exterior facelift of a 1950s house in the Mill Valley flats.
2018
Matilda, Mill Valley
A new craftsman-styled bungalow in the Sycamore Park neighborhood, with four bedrooms and a rear deck shaded by a wood and steel trellis.
2016
Lovell, Mill Valley
A trellis of steel and painted wood slats over a deck with canyon views, made to dapple the sun and give the deck a sense of place.
2013
Sunnyside, Mill Valley
A small flat and the studio apartment below it, joined into a 1,500-square-foot two-story house two blocks from downtown.
2021
Monte Mar, Sausalito
A hillside home opened to the Bay: the kitchen joined to the living and dining rooms, the lower floor more than doubled by excavation, and a new exterior stair.
2018
Johnson, Sausalito
A bay window addition and the renovation of a kitchen and bath in a 1,040-square-foot unit.
2012
McCart Court, Tiburon
A failing 1960 house rebuilt with a three-part roof that keeps the uphill neighbor’s view.
2009
Cove, Belvedere
A much-added-onto cottage brought together with consistent materials and detailing.
— Local review
Marin is not one jurisdiction
As of November 2026, except Sausalito’s code findings, which are from the code as it read in August 2022. Confirm the current requirements with the city, town or County before relying on this summary.
Each city and town in Marin runs its own design review, and properties outside any city limit are reviewed by the County of Marin. A Mill Valley mailing address, for example, can be in the City of Mill Valley or in unincorporated County land. The first step on any project is to find out which applies. Here is what the four towns where we have built say about their own processes.
Sausalito. Projects go to City staff or to the Planning Commission depending on size, height and views. The Commission must find that a project minimizes obstruction of public views and of primary views from private property. Story poles go up at least ten days before the hearing.
Mill Valley. The Planning Commission or the Zoning Administrator decides, depending on the project. Story poles are installed 10 days before the hearing. The City states that it has no view ordinance. Its Housing Element gives about 2 to 3 months for Zoning Administrator approval and about 3 to 4 months for the Planning Commission, for projects that meet City standards.
Tiburon. Design review is generally required for any addition or exterior remodel. Additions under 500 square feet are generally decided by staff, larger ones and new homes by the Design Review Board. Neighbors within 300 feet are notified of a hearing.
Belvedere. Planning staff review takes about 50 days on average and Planning Commission review about 90 days, according to the City.
Read more in our Journal: guides to design review in Sausalito, Mill Valley and Tiburon and Belvedere, a guide to BCDC permits for bayfront homes, and the stories behind Sarah, Monte Mar, Bay, Molino and Meadow.
Sources: City of Sausalito, Planning Permit Forms & Guidelines, and Municipal Code Chapter 10.54 (read from a copy archived in August 2022); City of Mill Valley, Design Review Application Submittal Checklist, Single-Family Residential Design Guidelines and 2023-2031 Housing Element, Appendix F; Town of Tiburon, Start Your Project; City of Belvedere, Planning & Building Review & Approval. Read on November 14, 2026.
— Questions
Questions about working with us in Marin County
Where in Marin County do you work?
Our work focuses on Southern Marin. The portfolio includes projects in Mill Valley, Sausalito, Tiburon and Belvedere, and our office is in Sausalito.
What kinds of Marin projects do you design?
Mostly renovations and additions to existing houses. We have also designed a new house in Mill Valley, a rebuilt house in Tiburon, a garden shed, a deck trellis and the student center at Tamalpais High School.
Is design review the same across Marin County?
No. Each city and town has its own process, thresholds and schedule, and unincorporated areas are reviewed by the County of Marin. Sausalito gives particular weight to views, for example, while Mill Valley states that it has no view ordinance.
Do you work on hillside and view lots?
Yes. Sarah in Mill Valley sits on a bench notched into the hillside. At Monte Mar in Sausalito we excavated into the hill to more than double the lower floor. At McCart Court in Tiburon the roof was shaped to keep an uphill neighbor view.
Planning a project in Marin County?
Tell us about your house and what you would like to change. You can also read how we work and how we charge on our Services & Fees page.
Town by town: Sausalito, Mill Valley, Tiburon and Belvedere. Across the bridge: San Francisco.