Garage Conversion ADU in Burlingame - Plans, Permits & Build, One Fixed Price

ADU in Burlingame, CA

Most Burlingame ADUs start with a design and permitting question: will the city’s tree protection ordinance, the lot shape, and the age of the house allow what you’re planning? We design, permit, and build ADUs in Burlingame under one contract at one written price, and we’ve found that the difference between a smooth project and a stalled one almost always comes down to how early the arborist and the structural engineer are brought into the conversation. Call (971) 497-2402 to start with a written price, not a sales pitch.

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Why Burlingame Homes Are Different

Burlingame’s residential core is dominated by 1920s to 1950s Craftsman bungalows and Spanish Colonial Revival homes on roughly 50-by-100 to 125-foot lots, most with original detached one-car garages. That stock makes garage conversions the dominant ADU pathway here, but it also means the work regularly triggers main panel upgrades from 100A to 200A, cast-iron lateral replacement, and cripple-wall seismic retrofitting that has to be folded into the ADU permit rather than treated as a separate job.

The city’s identity as the “City of Trees” creates a permitting obstacle that is genuinely uncommon in neighboring Peninsula cities. Burlingame’s municipal tree protection ordinance requires arborist review and often a formal tree protection plan whenever ADU foundation excavation or utility trenching falls within a protected tree’s root zone, and virtually every pre-1960 bungalow lot in the flats is canopied by mature oaks, redwoods, or sycamores that trigger this review. We routinely redesign to pier-and-grade-beam or post-and-pier foundations specifically to avoid root zone conflicts that rarely arise at this frequency in San Mateo, Millbrae, or San Bruno.

The marine layer is another factor. Burlingame sits in a persistent fog corridor compressed between the bay and the Coast Range foothills, sustaining elevated relative humidity most of the year. ADU shells here benefit from robust vapor barriers, rainscreen exterior cladding, and positive sub-slab drainage that would be considered over-spec in drier South Bay or Central Valley markets. These are not optional upgrades in Burlingame; they’re what keeps the building dry.

Our Main Burlingame Services

Two ADU pathways account for most of the work we do in Burlingame: converting the original detached garage, and building new in the rear yard. Both start with the same written-price discipline and the same attention to tree protection.

Garage Conversion ADU in Burlingame

Most Burlingame garages from the 1920s through 1950s are detached, single-car, and sized just under the 500-square-foot mark that keeps state-level ADU fees low. The conversion itself is usually the fastest path to a rentable unit, but the existing slab and foundation need a structural read before we commit to a number. We check slab thickness, footing depth, and the cripple walls, then fold any seismic retrofit into the permit set. Burlingame’s tree ordinance can also affect the trench route for the new sewer lateral, so we coordinate the arborist early. See Garage Conversion ADU in Burlingame for the full scope.

New Detached ADU in Burlingame

A new detached ADU in a Burlingame rear yard gives you more layout freedom than a garage conversion, but it puts the foundation directly into root zones more often. On canopied lots west of El Camino Real, the foundation type (pier-and-grade-beam versus slab-on-grade) is usually decided by the arborist’s report, not the architect’s preference. We design the unit around those constraints from the first drawing, which keeps the permit review moving. See New Detached ADU in Burlingame for the full scope.

ADU Design & Permitting in Burlingame

The design and permit phase is where Burlingame projects either gain momentum or get stuck. Because most lots in the flats are canopied by mature oaks, redwoods, or sycamores, Burlingame’s tree protection ordinance means a formal arborist review and often a tree protection plan must accompany your foundation and trenching drawings, and the building counter will flag any utility route that crosses a protected root zone. We produce the permit set as the core product, not an afterthought: every drawing is prepared to pass Burlingame review the first time. Our ADU Design & Permitting service covers the full drawings-to-approval sequence under the same written price.

Site Assessment

Signs you need it

You have an older Burlingame lot with mature trees, an existing garage, or a rear yard you suspect has drainage issues.

What it costs in Burlingame

Site assessment typically runs $850-$1,500, and on Burlingame lots with protected trees the arborist review is usually an additional $400-$750.

How we do it

We measure the lot, map the tree locations and root zones, check the existing structures, and deliver a written site report with the constraints named, including any tree ordinance triggers.

ADU Design & Blueprints

Signs you need it

You know what you want the ADU to do (rental, family, office) but need a buildable design that will pass Burlingame’s review.

What it costs in Burlingame

Design work for a detached ADU typically runs $8,000-$15,000, while interior conversions and JADUs come in lower at $4,000-$10,000.

How we do it

We draw the full permit set, including site plan, structural sheets, Title 24 energy compliance, and any tree protection plan the City of Trees requires.

Permit Application

Signs you need it

You have drawings already, or you suspect your project will trigger tree, setback, or historic-district review at the Burlingame counter.

What it costs in Burlingame

Permit application and city coordination typically run $3,000-$7,000, on top of the actual city permit fees, which vary by project scope.

How we do it

We package the full submittal, respond to plan-check comments, and track the permit through approval so you don’t sit in a plan-check queue unanswered.

What ADU Design & Permitting Costs in Burlingame

How long does ADU permitting take in Burlingame?

Plan on 4 to 7 months from submittal to issued permit in Burlingame, longer if tree protection review or a setback variance is involved. Early arborist coordination is the single biggest lever to shorten that timeline.

Does Burlingame require a tree protection plan for every ADU?

Not every ADU, but most. If foundation excavation or utility trenching falls within a protected tree’s root zone, yes, and the flats are dense with mature oaks, redwoods, and sycamores.

Junior ADU & Interior Conversion in Burlingame

For Burlingame homes where the rear yard is small or fully canopied, converting existing interior space into a Junior ADU or attached unit is often the only path that avoids tree-ordinance entanglement entirely. These projects stay inside the building envelope, so they typically skip the arborist review that governs backyard work, and they let you add a rentable unit without sacrificing the yard. Our Junior ADU & Interior Conversion service handles the design, the permit set, and the build under one written price.

Interior JADU

Signs you need it

You have an oversized primary bedroom, a finished basement, or a large utility room in a Burlingame bungalow you’d like to convert to a rentable Junior ADU.

What it costs in Burlingame

An interior JADU typically runs $65,000-$140,000, including the separate entry, kitchenette, and bathroom the state requires.

How we do it

We design within the existing footprint, add the required separate entry, and build the kitchenette, bath, and utility connections with a written price before work starts.

Room-to-ADU Conversion

Signs you need it

You have a Burlingame home with a large formal dining room, sunroom, or attached garage bay that gets used once a year, and you want it earning rent.

What it costs in Burlingame

A room-to-ADU conversion typically runs $80,000-$180,000, depending on kitchen, bath, and whether a separate exterior door already exists.

How we do it

We reframe the interior, add the kitchen and bath, install the separation wall, and handle the electrical and plumbing changes under one permit.

What Junior ADU & Interior Conversion Costs in Burlingame

Does a JADU in Burlingame need its own parking space?

No. Junior ADUs are exempt from parking requirements under state law, which is a real advantage on Burlingame’s narrow lots where a detached ADU would consume the only off-street parking.

Can I add a JADU to a Burlingame home with a 100A panel?

Sometimes. A JADU with an electric cooktop and no laundry may fit on a 100A panel, but most Burlingame homes we see still need the 200A upgrade. We’ll tell you which path applies in the written scope.

ADU Site Prep & Utilities in Burlingame

Site prep in Burlingame is where tree protection, old cast-iron, and the marine layer all meet. The city’s building counter is known locally for catching utility trench routes that cross root protection zones of protected street trees, a flag that contractors from San Jose or the East Bay often don’t anticipate, and that single correction can reset a permit by weeks. Our ADU Site Prep & Utilities service treats the underground work as a designed system, not a surprise to be discovered mid-dig.

Foundation & Grading

Signs you need it

Your Burlingame rear yard slopes, holds water after rain, or sits under a mature oak or redwood canopy that constrains where you can dig.

What it costs in Burlingame

Foundation and grading typically run $30,000-$70,000, and pier-and-grade-beam designs in root zones run toward the top of that range.

How we do it

We survey grade, design the foundation type around tree roots and drainage, and build the sub-slab drainage and vapor barrier the marine layer demands.

Electrical Panel Upgrade

Signs you need it

Your Burlingame bungalow still has a 100A panel, and the ADU will add a kitchen, heat pump, or EV charger load.

What it costs in Burlingame

A 200A panel upgrade typically runs $3,500-$7,500, depending on the existing service location and whether the meter needs to move.

How we do it

We replace the panel, coordinate the PG&E disconnect, and wire the ADU subpanel as part of the same permit and the same written price.

Plumbing Lateral

Signs you need it

Your Burlingame home still has cast-iron pipe in the ground, and the ADU needs its own sewer or water connection.

What it costs in Burlingame

Plumbing lateral replacement typically runs $6,000-$18,000, with Burlingame trench routes across tree roots adding real cost.

How we do it

We scope the trench route with the arborist’s map in hand, replace the lateral in one pull, and backfill and compact to city standard.

What ADU Site Prep & Utilities Costs in Burlingame

Will Burlingame make me replace my sewer lateral for an ADU?

Often, yes. Burlingame’s building department regularly requires lateral replacement or lining when the ADU adds a second kitchen or bath, and cast-iron laterals from the 1920s-1950s are common here.

Can I dig my own trench for the ADU utilities in Burlingame?

You can, but we don’t recommend it. Protected root zones, gas line depths, and compaction standards make a wrong trench an expensive correction. We include the trench work in the written price.

Brands We Service in Burlingame

We specify and coordinate prefab and modular systems from Abodu, Cover, and Dvele within the same single contract, and we stock the common James Hardie trim and siding profiles used on Burlingame ADUs locally. Parts lead time for those systems is typically 2 to 4 weeks once the permit is issued. See our brands for the full list.

Pricing for ADU in Burlingame, CA

Neighborhoods We Serve in Burlingame

We work across Burlingame’s flat, canopied neighborhoods west of El Camino Real and the hillside streets above it. Response time for an initial site visit is typically within one week, and for permit-ready projects we can often start drawings sooner.

• Easton Addition
• Burlingame Terrace
• Ray Park
• Lyon Hoag
• Country Club

Service Area - Cities Near Burlingame

Our crews serve Burlingame and the surrounding Peninsula, including San Mateo, CA, San Bruno, CA, Belmont, CA, and South San Francisco, CA. Scheduling is coordinated from our Bay Area office, so the estimate and the build are handled by the same team.

FAQs About ADU in Burlingame