ADU design and construction built for Kentfield properties
Kentfield is a quiet, wooded community in central Marin, and the homes here reflect it: established residences on large, often sloping lots, mature oaks and redwoods, and a refined, understated character that owners care about preserving. When a Kentfield homeowner starts thinking about an accessory dwelling unit, the brief is rarely just "add a small building." It is usually about housing aging parents nearby, creating a private guest suite, setting up a real home office detached from the main house, or adding long-term flexibility to a property the family intends to keep for decades.
That ambition is exactly why ADU design and construction in Kentfield is harder than it looks from the curb. The land is the first constraint. Slope, drainage, tree protection, and the way an unincorporated Marin lot sits among its neighbors all shape where an ADU can actually go and how it has to be built. The second constraint is taste. A high-end Kentfield client does not want a generic prefab box dropped in the side yard. They want a structure whose roofline, materials, and proportions read as a deliberate extension of the main house and the wooded setting around it.
Why a design-build approach fits ADUs here
New Key Construction is a Bay Area design-build firm, which means one team carries your ADU from first sketch through final inspection. That single difference solves most of the friction that derails ADU projects in Marin.
In the traditional path, you hire a designer or architect, wait for drawings, then send those drawings out to bid and discover the real cost only after the design is locked. With design-build, design and construction sit at the same table from day one. We design to your budget instead of designing in a vacuum and pricing it later. You get priced options up front, so you are choosing between real, costed directions rather than approving a drawing and hoping the number lands. And because the people who will build the ADU help shape it, the design stays buildable on a sloped, tree-covered Kentfield lot rather than becoming a problem to value-engineer after the fact.
We also produce 3D renderings before permits. For an ADU that has to belong on a refined property, seeing the massing, the windows, the materials, and how the unit sits relative to the main house, all before drawings go to the county, is the difference between a confident decision and an expensive surprise.
The Kentfield permitting reality
Kentfield is unincorporated, so an ADU here goes through Marin County for planning and building review rather than a city department. That matters for scheduling and for design. County review in a wooded, large-lot area typically gives weight to issues like tree protection, setbacks, drainage and grading on sloped ground, septic capacity where a property is not on sewer, and how new structures relate to neighbors and the natural setting.
California's statewide ADU law has, in recent years, made it meaningfully easier to add a unit to a single-family property than it once was, and that framework applies in unincorporated Marin. But "easier" is not "automatic." Each lot tells its own story, and a credible answer about what your specific property allows comes from checking it against current county and state requirements, not from a generic promise. We treat the permit path as part of the design work, not an afterthought, so the unit we draw is the unit the county can approve.
What we handle, end to end
- Feasibility and a site walk to understand slope, trees, access, and where an ADU genuinely fits
- Concept design with priced options, so cost is part of the conversation from the start
- 3D renderings before permitting, so you approve a design you can actually see
- Construction drawings and the Marin County submittal coordinated by the team that designed it
- Construction by the same firm, with one point of accountability through final inspection
Whether the goal is a detached cottage tucked into the trees, a unit built over or beside a garage, or a conversion of existing space, the process is the same: design and build under one roof, priced honestly, rendered before you commit.
Built to match the main house
The detail that separates a good Kentfield ADU from a forgettable one is continuity. Siding that echoes the primary residence, a roof pitch that belongs to the same family of forms, window proportions that line up, and a footprint that respects the trees rather than fighting them. Because we design and build as one team, those decisions hold from rendering to reality instead of getting lost in a handoff between separate companies.
If you are weighing an accessory dwelling unit in Kentfield, the most useful first step is a conversation about your lot and your goals. From there we can lay out the realistic paths, the priced options, and what the county will want to see.
FAQ
Do I work with Marin County or the town of Kentfield for an ADU permit?
Kentfield is an unincorporated community, so an ADU there is permitted through Marin County rather than a separate city government. We coordinate the planning and building submittals with the county as part of the project, and because the same team designs and builds the unit, the drawings we submit reflect what we intend to construct.
What does design-build actually change for my ADU project?
It means one company handles design and construction instead of two. You get priced options early, the design stays anchored to your budget, and there is a single point of accountability from the first concept through final inspection. It removes the usual gap where a design is approved and only later priced by a separate builder.
Can you build an ADU on a sloped or heavily wooded Kentfield lot?
Many Kentfield properties are sloped and tree-covered, and that is exactly why a site walk comes first. Slope, drainage, tree protection, and access all influence where an ADU can go and how it is built. We assess those conditions before committing to a design so the unit we draw is realistic for your specific lot.
Will I see the design before any permits are filed?
Yes. We produce 3D renderings before permitting so you can see the massing, materials, and how the ADU relates to your main house before drawings go to the county. Reviewing a design you can actually look at, rather than a flat plan, is how you make a confident decision.
How do I get started?
The first step is a conversation about your property and your goals, followed by a site walk in Kentfield. From there we outline the feasible directions, provide priced options, and explain what Marin County will expect for your specific lot.
