Detached Garage Conversion STANDALONE STRUCTURE · MAXIMUM PRIVACY · NEW UTILITY RUNS

The backyard structure with the most privacy — and the most utility work.

A detached garage sitting at the back of your lot is often the best candidate for a true independent ADU: it's already physically separated from the main house, which means more privacy for both households. It's also the conversion type most likely to need new utility trenching across the yard, which is the main thing that separates its cost and timeline from an attached garage conversion.

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What's Different About a Detached Structure

Separation is the advantage — and the reason the utility scope grows.

Because a detached garage isn't already connected to your home's electrical panel, water line or sewer, converting it into a livable space usually means trenching new utility runs across the yard — the single biggest driver of cost and schedule difference compared to an attached garage. We evaluate trenching distance, existing landscaping, hardscape and any easements as part of the initial site visit, since these are exactly the kind of site conditions that turn into change orders if they're found mid-construction instead of during planning. On the upside, a detached unit gets more design freedom for the entrance, layout and privacy than an attached conversion typically allows.

Detached backyard garage converted into a standalone ADU with new pathway

What's Included

A standalone unit, built with the utility and structural work a detached garage actually needs.

Utility Trenching & Routing

Electrical, water and sewer or septic lines routed from the main house or street connection to your detached garage, sized for full-time occupancy.

Foundation & Slab Evaluation

Detached garage slabs vary widely in age and condition — we assess whether the existing slab can be built on directly or needs supplemental footings.

Independent Entrance & Pathway

A dedicated walkway and entrance designed for the unit's actual use — a private rental, guest space, or family suite — separate from your main house's front door.

Privacy-Focused Window & Layout Design

Window placement and room layout designed around sightlines to and from the main house and neighboring properties, since a detached unit has more design flexibility here.

Full Permit Package

Complete ADU permit application covering the structural, electrical, plumbing and Title 24 scope specific to a detached conversion.

Why It Matters

Utility trenching is where detached-garage budgets go sideways if it's not scoped early.

The most common surprise on a detached conversion isn't the room itself — it's discovering mid-project that the trenching route crosses a mature tree's root system, an existing hardscape path, or a property line easement. We walk the actual trenching route during our initial site visit specifically to catch this before it becomes a change order.

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Service Areas

Also converting garages nearby.

Based in San Jose, working throughout Santa Clara, San Mateo and southern Alameda counties.

Atherton Belmont Campbell Cupertino Dublin East Palo Alto Foster City Fremont Gilroy Hayward Hollister Los Altos Los Altos Hills Los Gatos Menlo Park Milpitas Morgan Hill Mountain View Newark Palo Alto Pleasanton Redwood City San Carlos San Jose San Mateo Santa Clara Saratoga Sunnyvale Union City Woodside

FAQ

Questions homeowners ask us

Usually, yes, primarily because of the utility trenching required to reach a standalone structure — but the exact difference depends on the trenching distance and what's in the way (mature landscaping, hardscape, existing utility lines). We give you a specific comparison once we've walked your site.

Yes — a detached ADU is often the preferred configuration for a rental specifically because of the privacy and separation from the main house. Short-term rental rules still depend on your city's local ordinance.

We evaluate this during the feasibility review. Depending on the condition, we can sometimes repair or supplement the existing slab rather than requiring a full new foundation, but this needs to be confirmed case by case.

Often yes — running a new circuit from your main panel to a detached structure at ADU load levels typically calls for a sub-panel at the unit itself, which we size and scope based on your specific electrical service.

There's no fixed limit, but greater distance means more trenching cost and potentially more permit coordination for crossing property features. We assess this specifically for your lot during the site visit.

Free, No-Obligation Quote

Let's talk about your garage.

Tell us what you're converting it into — a JADU, an ADU, an office — and we'll get back to you with next steps, usually within one business day.

(408) 442-9136