General Contracting Built for Mill Valley's Hillsides and Heritage Homes
Mill Valley is not an easy place to build, and that is exactly why it rewards doing it right. Homes here climb the wooded slopes below Mount Tamalpais, tuck into redwood canyons, and perch on stilt-supported wings over terrain that rarely sits flat. A general contractor working in this town has to understand redwood-shingle cottages on Old Mill streets, Craftsman bungalows near downtown, the soaring glass walls of the Strawberry Point Eichlers, and the contemporary builds threaded into the hills above Cascade and Blithedale canyons. New Key Construction brings interior design and construction together under one roof so your Mill Valley project is handled by a single accountable team from first sketch to final walkthrough.
As a design-build firm, we do not hand you off between an architect, a designer, and a builder who have never met. One team designs the work, prices it, and constructs it. That continuity matters most on the kind of constrained, character-rich properties Mill Valley is full of, where a decision about a foundation, a roofline, or a window placement ripples through both the design intent and the construction budget at the same time.
One Team, Priced Options, and 3D Renderings Before Any Permit
Most frustration with home projects in Marin comes from surprises: a number that balloons after demolition, a design that looks nothing like what was promised, a permit timeline no one warned you about. We built our process to remove those surprises.
We give you priced options up front. Before you commit, you see real scope tied to real numbers, so the choices in front of you are clear rather than open-ended. We produce photoreal 3D renderings before any permit is pulled, which means you walk through your remodeled kitchen, new primary suite, or whole-home renovation visually and sign off on it while changes still cost nothing. And we run the project with white-glove management, a single point of contact who coordinates trades, inspections, deliveries, and the inevitable Mill Valley realities of narrow access roads and tight hillside lots.
That up-front clarity is doubly valuable here because design review can add the better part of a year to a hillside addition. When the city or county is going to scrutinize your project, you want a design that is resolved, rendered, and priced before it ever reaches a planner's desk.
Working Within Mill Valley and Marin County Jurisdictions
Where your home sits determines who reviews your project. Inside city limits, the City of Mill Valley Planning and Building divisions govern your permits, and major work such as new homes, significant additions, and projects that meaningfully alter the structure or site typically trigger Design Review. Planning Approval is often required before a building permit can be issued, and those approvals carry their own one-year clock with the possibility of extensions, so sequencing matters.
If your property sits in an unincorporated pocket of Marin County rather than within the city, you fall under Marin County Community Development Agency rules instead, where hillside and sloping-terrain provisions can change what is buildable on your lot. Either way, the steep grades, mature redwoods, creek setbacks, and wildfire-conscious requirements common across southern Marin shape what we design and how we phase construction. We plan around them deliberately rather than discovering them mid-build, and we keep your project moving through whichever jurisdiction holds the file.
This is also why multi-level floor plans, terraced layouts, and stilt-supported additions are so common in Mill Valley, and why the right contractor treats structure, access, and design as one connected problem.
Frequently Asked Questions
Do I need design review for a remodel or addition in Mill Valley?
It depends on scope and location. Major projects such as new homes, large additions, and work that significantly alters a structure or site generally require Design Review through the City of Mill Valley, and Planning Approval may be needed before a building permit is issued. We assess your specific property early and design with the applicable review process in mind from the start.
How long does the permitting process take here?
Timelines vary widely with the complexity of the work and whether design review applies. A hillside addition that goes through design review can take the better part of a year before construction begins, while simpler interior work moves faster. Because we render and price the design before submitting, our projects tend to enter review already resolved, which helps avoid back-and-forth delays.
What does design-build mean for my project budget?
It means one team designs, prices, and builds the work, so the budget is tied to the design from the beginning rather than discovered after the fact. We present priced options up front so you can weigh real scope against real cost before committing, which reduces the change-order surprises that come from splitting design and construction across separate firms.
Can you handle hillside and Eichler or mid-century homes?
Yes. Mill Valley's terrain and housing stock, from steep canyon lots to Strawberry Point's Eichlers and redwood-shingle cottages, call for a contractor who understands both the structural demands of building on slopes and the design sensitivity these homes deserve. Our combined design and construction team is built for exactly that range.
Will I see what the finished project looks like before construction?
Yes. We produce photoreal 3D renderings before any permit is pulled, so you can walk through the design visually and approve it while revisions are still free. Construction only begins once the design is locked, priced, and rendered to your satisfaction.
If you are planning a remodel, addition, or new build anywhere in Mill Valley or the surrounding Marin hills, New Key Construction can take it from concept to completion with one team, clear pricing, and a fully rendered design before the first permit. Reach out to start the conversation and see your project before it is built.
