Additions & ADUs in Mill Valley.
Room additions, second-story pops, ADU and JADU builds. We handle the survey, design coordination, permits, and construction.
Why GB Contractors for additions & adus in Mill Valley.
GB Contractors (legally Golden Bay Contractor LLC, founded by Manuel Escobar in 2004) is a family-owned, CSLB-licensed general contractor based in Novato. We've been doing additions & adus projects across Marin County for two decades. 30-minute drive from Novato via 101.
→ Hillside builds dominate here — drainage, retaining walls, and erosion control are non-negotiable.
→ Decades of experience with Mill Valley's mixed-stock: craftsman, mid-century, modern hillside.
→ Familiar with Mill Valley Planning and the design-review process.
What's in scope.
Typical line items on a additions & adus we'd run in Mill Valley. Every bid is line-item — no surprises.
- → Ground-floor additions and bump-outs
- → Second-story additions
- → Detached and attached ADUs
- → Junior ADU (JADU) conversions
- → Foundation work and structural integration
- → MEP rough-in and code compliance
- → Title 24 and energy compliance
- → Permits, including state ADU statute
Working in Mill Valley.
Mill Valley has strict design-review for projects visible from the public right-of-way, particularly in the wooded canyon neighborhoods. Tree-removal and grading permits are common requirements.
We've worked across Mill Valley's neighborhoods — Tam Valley, Strawberry, Homestead Valley, Sycamore Park, Cascade Canyon, downtown. Local knowledge of the building department, the design-review patterns, and the building stock isn't a marketing claim for us; it's two decades of repeat work.
Common questions about additions & adus in Mill Valley.
Does GB Contractors do additions & adus in Mill Valley?
Yes. Additions & ADUs is one of our core services and Mill Valley is squarely in our active service area. 30-minute drive from Novato via 101.
What does a additions & adus cost in Mill Valley?
Mid-range projects in our portfolio start around $150K. High-end builds with structural changes, premium materials, or custom cabinetry typically run $800K+. Mill Valley permitting and design-review can add to both timeline and cost — we factor that into bids up front.
How long does a additions & adus take in Mill Valley?
5 months to 12 months once construction starts, depending on scope and design-review timing. Mill Valley has strict design-review for projects visible from the public right-of-way, particularly in the wooded canyon neighborhoods. Tree-removal and grading permits are common requirements.
Are you licensed to work in Mill Valley?
Yes. GB Contractors (Golden Bay Contractor LLC) holds CSLB License #992507 (Class B General Building), valid statewide in California, and we're fully insured. We pull all required permits and handle inspections directly with the Mill Valley building department.
Other services in Mill Valley
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