Casa de RJ — Berkeley ADU
Casa de RJ  ·  Berkeley, California

Your backyard may be worth more than you think.

Detached accessory dwellings designed for Berkeley lots — approved ministerially, built to be lived in rather than rented out of obligation.

Check My Property +1 510-590-6291

Berkeley  ·  Peninsula  ·  Tri-Valley

Guest Residence

For family and long-term guests. A parent who wants to stay close without moving in.

Private Office

A quiet space outside the main home. Fifty feet of separation does more for focus than any interior room.

Future Flexibility

What it's for in year one is rarely what it's for in year ten.

Casa de RJ presents  ·  ADU Series

The Aurelian

Private. Modern. Effortlessly yours.

Three-dimensional isometric floor plan of The Aurelian — two bedrooms, two baths, and an open living, dining and kitchen core.
Bedrooms with en-suite baths flank an open core, so the long elevation stays free for glass.
Footprint
600–900 sq ft
Configuration
Up to 2 bed / 2 bath
Finish allowance
$110k – $165k
Inside the investment

A named allowance, not a vague line item.

Finishes are held at $110,000–$165,000 within the project investment, so you know what they're worth before anyone selects them. Landscape and utility connections are budgeted separately. Final scope is determined by level of customization.

Windows & doorsMarvin
Refrigeration & cookingSub-Zero
Plumbing fixturesKohler
Bath fittingsWaterworks
Bath cabinetry & mirrorsRobern
Hardware & lightingBuster + Punch
WallcoveringCole & Son
Cabinetry & millworkBuilt to the drawings

Renderings and specifications are illustrative. Final scope determined by site conditions and approvals.

Property criteria

Three things decide whether your lot works.

We check these before anyone draws anything. It's the difference between a project that moves and one that stalls in plan check.

1

Setbacks and buildable area

Four-foot side and rear setbacks, plus enough room left over for a building worth putting there.

2

Access

Machinery, equipment and material have to reach the back of the lot. On a Berkeley hillside parcel this is often the deciding factor.

3

Utility capacity

Water, sewer and electrical service able to carry the additional load. This is the line item that surprises people.

Berkeley  ·  BMC 23.306

No hearing. No appeal. No neighbor approval.

The most common reason people don't start is the one nobody says out loud: they expect the neighbors to fight it.

In Berkeley they can't. State law requires ADUs to be reviewed ministerially — a staff check against the rules, with no public hearing scheduled and no appeal available once it's approved. Your neighbors are mailed a courtesy notice within ten working days of your application. They're informed. They aren't asked.

Site-specific reviews — protected trees, hillside overlay, creeks, grading — can still apply to your parcel. Those are the ones worth checking early, and they're the reason we walk the lot first.

The investment

$450,000 to $1,200,000.

We put the number here because you'd rather read it now than hear it in your backyard. Where a project lands inside that range comes down to four things.

Size and program

A studio and a two-bedroom with a real kitchen are different buildings. Berkeley's standards set the ceiling; what you need sets the floor.

What the site hands you

Slope, access, utility runs, trees, and how far the sewer and panel sit from where the residence wants to go.

Level of finish

The structure is the structure. The $110k–$165k finish allowance is where the range opens up — and where you have the most control.

Whether the yard comes too

Designing the residence and the landscape as one project costs more than dropping a unit on a lawn. It's also the entire reason to hire us.

Budgets are discussed early, refined through design, and documented before construction starts. No vague allowances.

Project timeline

Twelve to sixteen months, start to certificate of occupancy.

Longer than a remodel. We'd rather you know that on day one than in month seven.

Phase one Pre-construction & design

2–4+ months. Feasibility, placement, and a design that will survive Berkeley plan check.

Phase two Permits

2–4+ months. Submittal, plan check, corrections, and the outside agency sign-offs your parcel triggers.

Phase three Building

4–8+ months. Site work through final inspection, then the landscape that makes it a residence.

The offer

The Private Property Review.

Forty-five minutes on your property. If the honest answer is that your lot is difficult or the numbers don't work, you'll hear it standing in the yard — not after you've paid for drawings.

STEP 1

Walk Your Property

Evaluate placement and access. Where the residence wants to sit, and whether we can get to it.

STEP 2

Review Feasibility

Size, scope and investment, against what your parcel and the Berkeley standards actually allow.

STEP 3

Outline the Build Plan

A budget and a preliminary design — so the next conversation is about a real project, not a hypothetical one.

Request a Private Property Review
How we work

The walk is free. The plans are not.

Nobody can bid your project without documents — not us, not the builder down the street. Somebody has to draw it, engineer it, and price it before a real number exists. That work is the second stage, and it's the one you pay for.

Stage 1  ·  No charge

Private Property Review

Forty-five minutes on your lot. We establish whether an ADU is feasible here, roughly where it sits, and what the parcel will and won't allow.

  • Placement and access
  • Setbacks, utilities, site conditions
  • An honest yes or no
Stage 2  ·  Fixed fee, credited to the build

Pre-Construction & Design

A signed agreement to produce the documents your project needs to exist. You own the set. If you build with us, the fee comes back off the contract.

  • Measured site plan and construction documents
  • Structural and Title 24 coordination
  • Permit-ready submittal set for Berkeley
  • Line-item finish budget, not a lump allowance
  • A real bid — from us, or from anyone you hand the set to
Stage 3  ·  Construction

Build

Fixed scope against a documented budget, built to the set you already approved. No vague allowances, no mid-project discovery of what the drawings never said.

  • Documented scope and schedule
  • Regular updates, clear landmarks
  • Landscape delivered with the residence

Paying for design separates the drawings from the builder. You keep the leverage — and a set you can bid competitively — instead of a free sketch that only one company can price.

City of Berkeley  ·  published fees

What the city charges, before anyone builds anything.

Most contractors won't put these on a webpage. Here they are.

Neighbor courtesy noticeCollected with the ADU building permit application
$500
Address assignmentNon-refundable, required before permit issuance. Junior ADUs exempt.
$250
Recorded deed restrictionFiled with Alameda County Clerk-Recorder. County recording fees apply.
Required
Plan check & inspectionCalculated on permit valuation. Pre-approved gallery designs are charged at 50% of standard plan check.
Varies
Land Use Planning impact feesNot assessed by the Land Use Planning Division
None

Published by the City of Berkeley, separate from the project investment above. We run your actual numbers through the city's Permit Fee Estimator during the review. Verify current fees with the city before relying on them.

Frequently asked

Questions worth answering before you start.

Do my neighbors have to approve it?
No. The city mails them a courtesy notice. State law requires ministerial review without a public hearing, and approved ADU permits aren't appealable. Site-specific reviews — protected trees, hillside, creeks, grading — can still apply to your parcel, and those are the ones worth checking early.
What is the realistic capital range, and what drives it?
Most of our ADU projects fall between $450,000 and $1,200,000, shaped by site conditions, size, level of finish, and whether the landscape is designed as part of the project. Finishes are held as a named allowance of $110,000–$165,000 within that total. Budgets are discussed early, refined through design, and documented before construction begins.
How long does a Berkeley ADU take?
Plan on 12 to 16 months from start to certificate of occupancy — roughly 2–4+ months of design and feasibility, 2–4+ months through permits, and 4–8+ months of construction. It's a longer runway than a remodel, and knowing that on day one is part of why we walk the lot before anyone draws.
How disruptive is this to my life?
Detached builds limit intrusion and preserve daily family routines. The work happens at the back of the lot rather than through your kitchen — one of the underrated arguments for building detached rather than converting.
Will this change my property taxes?
Building an ADU triggers an assessment. Your existing home isn't reassessed — the increase is based on the value added by the new unit. Your city or county assessor is the best resource for what that looks like on your specific parcel.
Does the ADU count toward my home's square footage?
A Junior ADU connected to the house by an interior door does count. A detached ADU does not. Worth confirming against your own parcel before you rely on it — we cover it during the review.
Can I rent it short-term?
No. Berkeley records a deed restriction before permit issuance that prohibits short-term rental and limits separate sale from the primary unit.
Does the city's pre-approved gallery actually save money?
Plan check drops to 50% and review generally moves faster, because the code review already happened once. But those designs can't be modified — alter one and you're submitting a new design under normal processing. Whether that's a good trade depends entirely on what you want.
Why do you charge for design and pre-construction?
Because no one can bid a project that hasn't been drawn. Plans, engineering and a line-item budget have to exist before any builder — including us — can give you a real number. We charge a fixed pre-construction fee for that work, you own the documents, and the fee is credited against your construction contract if you build with us. A free sketch isn't a bargain; it's a set only one company can price.
Is the Private Property Review really free?
Yes. The walk, the feasibility conversation and an honest answer about your lot cost nothing. What we charge for begins when we start producing documents.
What happens after I submit the form?
We review your address and project details. If your parcel and timeline align, we'll reach out to schedule the Private Property Review.
A detached Casa de RJ accessory dwelling at dusk, warm-lit, with a stone path through planted beds.
Berkeley  ·  Peninsula  ·  Tri-Valley

Building homes around people, not blueprints.

Request a Private Property Review (510) 590-6291

Casa de RJ  ·  CSLB #1084784  ·  DRE #02142285
[email protected]  ·  3494 Camino Tassajara, Danville CA 94506