San Francisco Bay Area
Room additions and ADUs in the Bay Area
On the Peninsula, in Silicon Valley and in the East Bay, adding space to the house you own is usually more practical than moving. Tulip helps you choose between a ground-floor addition, a second story and an ADU, a choice often settled by your city's design review, single-story overlays and protected trees, then designs, permits and builds it.
Most of our reviews come from Los Angeles clients; we're earning more in the Bay Area now.
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- Licensed, bonded & insured · CSLB #1059213 (opens in new tab)
- 20+ years of team experience
- Permits handled
- Supervisor on site daily
- 3D design included
What happens next
Three steps to a plan and a price
- Tell us about your projectAnswer a few quick questions about your home, the project, your budget and your timing. It takes about two minutes, and we reply within one business day.
- Free in-home consultationA Tulip project leader visits, walks the space with you and talks through your goals, budget and what your city will require. The visit takes about 45–60 minutes (up to 90 for larger projects), with no pressure and no obligation.
- A price, then design and contractAfter the visit we send a written summary with an approximate price and timeline, usually within 2–3 business days (4–7 for larger projects). We then develop the design with 3D renderings and set the final price in your contract, with payments tied to completed work. Nothing is ordered or built until you approve it in writing.
At a glance · Bay Area
- Typical budget
- $150K–$350K
- Design, permits and ordering
- 3–6 months
- Construction
- 4–6 months for an addition, 4–7 for an ADU
- Permits
- Your city's building and planning departments; additions often go through design review, while ADUs follow streamlined state rules
- Regional note
- Protected and heritage trees can limit where an addition or ADU can go
Typical budgets include design, permit preparation and construction; city permit fees are separate.
Real Tulip work
Room additions & ADUs by Tulip
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Projects are labeled with where they were built: in the Bay Area or by our Los Angeles team.
New-construction kitchen, framing to finish · ADU kitchen · Mar Vista, Los Angeles
ADU bathroom, framing to finish · ADU bath · Mar Vista, Los Angeles
Room additions & ADUs in the Bay Area
What decides the choice on a Bay Area lot
Bay Area cities shape the decision more than lot size alone. Some Eichler neighborhoods in Palo Alto and Sunnyvale are in single-story overlay districts, where a second story isn't allowed and a ground-floor addition or ADU is the way to grow. Elsewhere, daylight-plane rules, floor-area limits and design review shape how an addition looks from the street and from the neighbors' yards. ADUs follow state law, which limits how cities can restrict them and sets a 60-day decision clock for complete applications.
Trees are the other local factor. Palo Alto, Menlo Park, Los Altos and Saratoga protect certain oaks, redwoods and other large trees, and their root zones can rule out a footprint or require an arborist report and protection during construction. Seismic design and Title 24 energy compliance apply to every addition; we coordinate the engineering, energy calculations and any surveys as part of the project.
Bay Area office
- Sunday – Thursday
- 8am – 8pm
- Friday
- 8am – 4pm
- Saturday
- Closed
FAQ
Room additions & ADUs in the Bay Area: questions
Is my Bay Area house in a single-story overlay?
Your city's zoning map will show it; Palo Alto and Sunnyvale have single-story overlay districts in a number of Eichler neighborhoods. If you're in one, a ground-floor addition or an ADU is usually the way to add space, and we check this in the feasibility review.
What is a daylight plane, and how does it affect an addition?
It's an angled line, starting at a set height above the side property line, that the building can't cross. Several Peninsula cities use one to limit how tall an addition can be near the neighbors, which shapes rooflines and wall heights.
There's a protected tree where we want to add on. What now?
An arborist maps the tree's protection zone, and the footprint, foundation type or construction access may need to change; removal usually needs a city permit that isn't guaranteed. It's better to know before design than after.
How do Peninsula floor-area limits affect an addition?
Most Peninsula cities cap total floor area relative to lot size, and your existing house counts toward it. On some lots there's little room left, which can point toward an ADU, since ADUs are treated differently under state law.
Can we add a primary suite to a Los Altos or Cupertino ranch?
Often, yes. Single-story primary-suite additions are common on the larger lots there, within each city's setback, lot-coverage and floor-area limits. We check those numbers and any design review before design starts.
What warranty comes with the work?
Tulip's warranty is typically one year on workmanship from completion, plus manufacturers' warranties. Your exact terms are in your contract.
Where we work
Room additions & ADUs across the Bay Area
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