A free site visit, a check of what your lot allows and a written, line-item price.
Get your free estimateADU Company in Portola Valley, CA
Portola Valley is unlike any other town on the Peninsula. The lots are big, the hills are steep, and the ground itself is geologically restless. An ADU here isn’t a weekend project, and it isn’t a kit dropped onto a flat suburban pad. It’s a structure that has to sit correctly on a hillside, survive fire season, and meet some of the strictest geological reporting requirements in the Bay Area. At Lodgewick ADU Builders, we plan for all of that from the first site visit so the build doesn’t stall in the permit phase or surprise you with a floor-plan change you were never warned about. Call (669) 266-4319 to talk through what’s possible on your lot.
Why Portola Valley Homes Are Different
Most Portola Valley homes sit on multi-acre lots carved into the eastern slope of the Santa Cruz Mountains, with winding private roads, mature oaks, and very little flat ground. Many were built in the 1960s and 1970s as custom wood-frame houses, which means floor plans are irregular, septic systems are common, and the flat pad near the house is often already occupied. A detached ADU almost always means cutting into a hillside, shoring it properly, and managing drainage that will carry water away from both structures during winter storms.
Then there’s the geology. Portola Valley is laced with fault traces from the San Andreas system, and the town’s planning department routinely requires geotechnical reports, soil studies, and in some cases full geological reviews before a permit is issued. That’s months of prep before construction starts, and if the report comes back with landslide or liquefaction concerns, the engineering changes. We budget for that reality from day one, with a written price that accounts for known conditions, not a number that inflates once the report lands on your kitchen table.
Fire safety shapes materials here more than in neighboring towns. The combination of dense vegetation, steep terrain, and dry summers earns much of Portola Valley a high fire-risk designation, which means exterior cladding, vents, and even window framing have to meet Wildland-Urban Interface (WUI) codes. We specify fire-resistant materials like James Hardie siding on most Portola Valley ADUs, and we factor defensible space requirements into site placement from the start.
Our Main Portola Valley Services
Most Portola Valley homeowners come to us for one of three things: more living space attached to the main house, a garage that earns its keep as rentable square footage, or a fully detached ADU on a quiet corner of the lot. Each has its own page with pricing and details.
Home Addition Contractor in Portola Valley
On large Portola Valley lots, a home addition often makes more sense than an ADU when the goal is primary living space: a bigger kitchen, a first-floor primary suite, or a family room that opens to the hillside. The work involves matching the existing roofline, bringing the older structure up to current seismic code where the two connect, and managing the same geological and fire-safety requirements that apply to new construction. Slope and setback challenges are common, and we handle the engineering and permits as part of the same written price. Home Addition Contractor in Portola Valley
Garage Conversion Contractor in Portola Valley
A garage conversion is usually the fastest path to liveable square footage because the foundation and roof already exist. In Portola Valley, however, many garages were built into slopes or as separate structures with undersized footings, which means the conversion often includes foundation reinforcement, new drainage, and WUI-compliant exterior upgrades. We also coordinate with the town on owner-occupancy and parking-replacement rules that affect garage conversions differently than detached ADUs. Garage Conversion Contractor in Portola Valley
ADU Builders in Portola Valley
A detached ADU on a Portola Valley hillside begins with geology. We order the geotechnical report, design the foundation to stabilize the unit on the specific slope, and build with materials that satisfy the town’s wildfire code. Prefab systems from Abodu and Cover can shorten the on-site timeline meaningfully, especially when access is tight and flat staging space is scarce. Every ADU we build carries the 365-Day Done Right Promise in writing before any work begins. ADU Builders in Portola Valley
What happens when you call
- 1
A real person answersNo phone trees - you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Brands We Service in Portola Valley
We work hands-on with the ADU systems and materials that suit Portola Valley’s terrain and fire codes best. Abodu and Cover prefab units speed up construction on tight hillside sites where staging room is limited. Tuff Shed provides reliable outbuilding shells for simpler projects, and James Hardie siding covers the WUI requirements without sacrificing the look homeowners expect in this town. Our brands page has the full picture.
Pricing for ADU Company in Portola Valley, CA
| Service | Typical range in Portola Valley |
|---|---|
| Detached ADU (site-built, 1 bed) | $325,000 – $450,000 |
| Detached ADU (site-built, 2 bed) | $425,000 – $600,000 |
| Prefab ADU (Abodu or Cover, 1 bed) | $250,000 – $350,000 |
| Prefab ADU (Abodu or Cover, 2 bed) | $350,000 – $475,000 |
| Garage conversion (finished, 1 bed) | $180,000 – $280,000 |
| Garage conversion (finished, 2 bed) | $250,000 – $380,000 |
| Home addition (400 – 600 sq ft) | $280,000 – $420,000 |
| Home addition (600 – 1,000 sq ft) | $420,000 – $700,000 |
| Foundation upgrade (slope stabilization) | $35,000 – $90,000 |
| Geotechnical report and permit package | $15,000 – $40,000 |
Portola Valley prices run higher than most Peninsula towns because of the geology. The hillside work, retaining walls, deep footings, and WUI-compliant cladding all add cost that flatland builds never see. What doesn’t change is the price itself: we put it in writing before work starts, and that number holds unless the town’s geologist turns up something we couldn’t have known at the first site visit, in which case we show you the report and agree on any adjustment together before anything changes.
Neighborhoods We Serve in Portola Valley
We cover the entire Town of Portola Valley, from the western ridgelines down to the valley floor and across both sides of Portola Road and Alpine Road. Response time for a first site visit is typically under one week, and we schedule around the town’s permit-office hour practices to keep projects moving.
- Portola Valley Ranch
- Los Trancos Woods
- Blue Oaks
- Central Portola Valley (along Portola Road)
- Alpine Hills
Service Area – Cities Near Portola Valley
If you’re just over the town line, we regularly serve homeowners in Los Altos, CA and Palo Alto, CA to the north, Santa Clara, CA across the valley, and Los Gatos, CA on the other side of Highway 17. Each city has its own permitting culture, and we adjust accordingly.
Serving Portola Valley, CA - Our Local Coverage Area
We’re based in the Portola Valley area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About ADU Company in Portola Valley
A detached ADU in Portola Valley typically takes 12 to 18 months, with the geological report and permit review consuming four to six of those months before construction begins. Prefab systems from Abodu or Cover can compress the build phase, but the town’s geological review timeline stays the same regardless of construction method. Call (669) 266-4319 to get a schedule mapped to your specific lot.
No. We order the geotechnical and geological reports as part of our written price, and we handle the soil studies, permit submittals, and any follow-up the town requires. You get one price that includes the reports, not a surprise invoice from a third-party geologist.
Yes. We take on smaller foundation and drainage repairs under the same written-price and 365-Day Done Right Promise rules as full ADU builds. If your goal is to fix a slope or footing problem before deciding on a larger project, call (669) 266-4319 and we’ll price it the same way: a written number before anything starts.
For a free estimate on an ADU, home addition, or garage conversion in Portola Valley, call Lodgewick ADU Builders at (669) 266-4319. A live person answers, every time.
What happens when you call
- 1A real person answersNo phone trees - talk to a local adu pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3We come out and measureLicensed & insured, at a time that suits you - the visit and the quote are both free.
- 4You get the price in writingLine-itemed, yours to keep, and nothing starts until you say go.
What Portola Valley Customers Say
"Converted our garage into a rental studio. The crew was respectful of the neighbors and kept the site clean. It's bringing in rent now and paid for itself faster than I expected."
- Grace Yoon"Built a backyard unit for my mother in law. They handled the permits, gave me a real timeline, and stuck to it within a few days. The written price is what we paid, which anyone who's done construction knows is rare."
- Dennis Fairchild"Added a suite for my dad. They walked us through every cost before a hammer swung and stuck to it. The written price is what we paid, no change orders."
- Ingrid Salazar
