What is a JADU and how is it different from an ADU?

A JADU (Junior ADU) is a unit up to 500 sqft built inside the footprint of an existing single-family house — usually a converted bedroom or garage. It requires owner-occupancy and is faster/cheaper to permit than a full ADU.

Can I have both a JADU and an ADU on my LA lot?

Yes — state law allows one JADU plus one ADU on most single-family lots in LA. The combination is often the best path for multi-generational living plus rental income.

What is a JADU and how is it different from an ADU?

A JADU is a unit up to 500 sqft built inside the footprint of an existing single-family house — usually a converted bedroom or garage. It requires owner-occupancy and is faster/cheaper to permit than a full ADU.

Can I have both a JADU and an ADU on my Bay Area lot?

Yes — state law allows one JADU plus one ADU on most single-family lots in the Bay Area. The combination is often the best path for multi-generational living plus rental income.

California JADU Builder.

A Junior ADU carves up to 500 sqft out of an existing single-family house, typically a converted bedroom or attached garage bay. It is the lightest-touch path to a permitted rental unit in LA — and the owner can keep occupying the main house. We handle the plan set, the LADBS permit, and the build.

A Junior ADU carves up to 500 sqft out of an existing single-family house in the Bay — typically a converted bedroom or attached garage bay. It is the lightest-touch path to a permitted rental unit, the owner keeps occupying the main house, and most Bay cities can over-the-counter permit when the plan set is clean.

Los Angeles

$95K – $180K all-in

Existing plumbing wall proximity and whether the entrance already exists drive the band.

Timeline — Plan on 6–10 weeks for design + LADBS permit, then 8–12 weeks on-site.

Los Angeles JADU Builder →

San Francisco Bay Area

$115K – $210K all-in

Existing plumbing wall proximity and whether the entrance already exists drive the band.

Timeline — Plan on 8–12 weeks for design + city permit, then 10–14 weeks on-site.

San Francisco Bay Area JADU Builder →

What we actually build inside jadu builder.

Every component below has its own field page — materials, California code notes, cost bands, common mistakes, and FAQ.

Scope — what we deliver.

Feasibility check — interior wall layout, plumbing access, exterior entry
Kitchenette, efficiency bath, and bedroom buildout
Separate exterior entrance, fire-rated demising wall if required
Owner-occupancy deed restriction and LADBS sign-off
Sub-panel, plumbing tie-in, mini-split HVAC

Permits look different in LA vs the Bay.

Los Angeles — permit notes

JADUs require an owner-occupancy deed restriction in LA — the homeowner must live in either the main house or the JADU.
Maximum 500 sqft of interior conversion under California JADU law (Gov Code §65852.22).
An efficiency kitchen is allowed (no full range required) but the unit still needs a separate exterior entrance.
Most JADUs can be permitted over-the-counter at LADBS when the plan set is clean.

Bay Area — permit notes

JADUs require an owner-occupancy deed restriction across all Bay jurisdictions — the homeowner must live in either the main house or the JADU.
Maximum 500 sqft of interior conversion under California JADU law (Gov Code §65852.22).
Most Bay cities allow JADUs as a counter-permit when the plan set is clean — SF is the exception (full DBI review).
An efficiency kitchen is allowed (no full range required) but the unit still needs a separate exterior entrance.

How we think about jadu builder.

An ADU is the single highest-ROI piece of construction most California homeowners will ever do — but only when the building separates cleanly from the main house mechanically, acoustically, and legally. We design every unit as if it will be rented to a stranger on day one: independent panel, independent water shutoff, independent address, independent waste line where the lot allows.

The cheap way to build an ADU is to share systems with the primary residence. It works on paper. It fails in year three when the tenant calls the homeowner about a water heater that lives in the main-house garage. Separation costs 6–9% more up front and recovers it within the first turnover.

We refuse to value-engineer the envelope. The walls, roof, and windows are what the building still has in 30 years; the cabinets and fixtures are not. Spend on R-25 walls, R-49 roof, low-e dual-pane windows, and a properly detailed weather barrier before you spend on stone counters.

The schedule, written out.

Week 0
Feasibility + zoning
Site walk, address-specific zoning pull (LAR1, RM, SF RH-1, etc.), setback + FAR check, easement + utility-locate, soils note. Output: go / no-go memo with realistic budget range.
Week 1–3
Schematic design
Two or three plan options, exterior massing, daylight study, septic / sewer routing, panel-load + HVAC sizing. Output: agreed plan + outline spec.
Week 3–8
Construction documents + Title 24
Stamped architectural, structural calcs, MEP, Title 24 energy report, soils where required. Output: permit-ready set.
Week 8–16
Permit + plan check
City intake, back-and-forth corrections, utility-coordination letters (LADWP, PG&E, EBMUD, SFPUC), school fee + capacity fee assessment, permit issuance.
Week 16–22
Site prep + foundation
Demo, excavation, underground plumbing + electrical, formwork, rebar, pour, foundation inspection.
Week 22–30
Framing + dry-in
Framing, roof sheathing, windows, exterior weather barrier, roofing. Building goes from concrete to lockable shell.
Week 30–38
MEP rough + insulation
Rough electrical, plumbing top-out, ducted heat-pump or mini-split, HERS verification, insulation, drywall.
Week 38–48
Finish + close-out
Cabinets, tile, flooring, paint, fixtures, appliances, exterior hardscape, final inspections, separate-meter release, occupancy.

Materials & assemblies.

Component	Default spec	Why
Wall assembly	2x6 @ 16" o.c. + R-23 batt + ½" ZIP-R + ¾" rainscreen	Continuous insulation closes the thermal bridge that meets Title 24 without crippling the layout.
Roof	R-49 raised-heel truss + radiant barrier sheathing + 30-yr architectural shingle or standing-seam metal	Standing-seam wins on a flat-roof or low-slope detached ADU; shingle is fine on a matched-pitch attached.
Windows	Vinyl or fiberglass, U ≤ 0.30 / SHGC ≤ 0.23, dual-pane low-e	Aluminum frames fail T-24 in almost every CA climate zone.
Heating + cooling	Ducted heat pump (single zone) or ceiling-cassette mini-split	Heat pumps drop ducting complexity and are now cheaper to operate than gas.
Hot water	Heat-pump water heater, 50–65 gal, separate dedicated 240V circuit	Tankless gas is no longer the default — heat pump qualifies for rebates and avoids gas-line trenching.
Subpanel	100A or 125A subfed from main, ground rod at unit, independent disconnect	Independent disconnect is what enables clean future separate-meter conversion.

Hidden costs we flag up front.

Line item	Range	When it hits
Service-panel upgrade	$3K–$12K	main panel is < 200A and you're adding heat pump + EV
Sewer-line replacement	$8K–$28K	pre-1970 clay or cast iron lateral fails camera inspection
Survey + ALTA	$2.5K–$6K	ADU sits within 5 ft of a property line
Tree-protection / removal	$1.5K–$8K	protected tree within drip line of construction
Separate water meter	$5K–$15K	rental and lender requires it
Sprinkler retrofit	$6K–$18K	primary house lacks NFPA 13D and addition triggers it

cheaper alternatives

What we'd consider — and what we wouldn't.

Pre-fab / modular ADU
Lower base price but rarely cheaper all-in once foundation, utility connections, and crane delivery are included; weak on site-specific zoning fit.
Conversion only (no detached)
Faster + cheaper but loses the rental separability and the ROI of a true second dwelling.
Owner-builder
$40K–$80K savings on paper, but most stall in plan-check and lose 6–18 months of carrying cost.

pitfalls — takeover-job patterns

Mistakes to avoid.

Sizing the panel + HVAC for today instead of an electrified future — re-doing it 5 years later costs more than oversizing now
Skipping a sewer-camera before pouring foundation — finding a collapsed lateral after the slab is a $30K+ surprise
Choosing a contractor who has never done a separate-meter coordination — DWP / PG&E paperwork is its own multi-month project
Cheaping out on the weather-resistive barrier — a $400 detail today becomes a $40K mold remediation in year 7

JADU Builder — Los Angeles.

JADU Builder — Bay Area.

In short.

What is a JADU and how is it different from an ADU?: A JADU (Junior ADU) is a unit up to 500 sqft built inside the footprint of an existing single-family house — usually a converted bedroom or garage. It requires owner-occupancy and is faster/cheaper to permit than a full ADU.
Can I have both a JADU and an ADU on my LA lot?: Yes — state law allows one JADU plus one ADU on most single-family lots in LA. The combination is often the best path for multi-generational living plus rental income.
How much does a JADU cost in Los Angeles?: Most LA JADUs land between $95K and $180K all-in. Existing plumbing proximity and whether the entrance already exists are the biggest swing factors.
What is a JADU and how is it different from an ADU?: A JADU is a unit up to 500 sqft built inside the footprint of an existing single-family house — usually a converted bedroom or garage. It requires owner-occupancy and is faster/cheaper to permit than a full ADU.
Can I have both a JADU and an ADU on my Bay Area lot?: Yes — state law allows one JADU plus one ADU on most single-family lots in the Bay Area. The combination is often the best path for multi-generational living plus rental income.

More we build.

Got a jadu builder project in mind?

Send us the address. We'll pull local zoning, setbacks, and jadu builder feasibility before you spend on drawings.

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