We hired Jimmy for a garage to ADU conversion project. The project was completed quickly, with diligent work from Jimmy's team, resulting in a finished product that exceeded our expectations!

Multifamily ADU Builder in Chino, CA
Own a rental property? You may be able to add units. J.O. Construction builds duplex and multi-family ADUs for investors around Chino. Call (951) 436-6568.
Call (951) 436-6568Send us your project



Recent multi-family ADU projects
Real jobs, newest first. Dates are the month we posted each stage on our Instagram.

A duplex ADU in San Clemente: two rental units on one lot
A San Clemente property and a plan for two units on it, designed to get the most out of the lot, with interior designer 8a Interiors.

A multi-family ADU in Fontana, pour to finish line in about 4 months
A multi-family ADU project on a Fontana property.
What is included
- Two units stacked or side by side
- New detached units on a property with several already
- Fire separation between units
- Utilities planned per unit
- Meters, parking and trash enclosures raised early in plan check
- Shared foundation work and inspections when built together
The job, in three frames
How the job runs with J.O. Construction, in the order it happens.
1
Step 1: Plan for two
Both units laid out at once, with meters, parking and trash settled before plan check asks.
2
Step 2: Frame with fire separation
The wall between units is built to the fire rating the plans call for.
3
Step 3: Two units, two entries
Each unit finished with its own entry, kitchen and bath.
What counts as a multi-family ADU
Two units stacked or side by side, or new detached units added to a property that already has several. The plans go through the same ADU process, with more attention to fire separation and utilities.
Multi-family ADU projects near Chino
The San Clemente duplex ADU is finished. The Fontana multi-family project went from foundations to finishes in view of our followers, stage by stage.
What Chino investors should plan for
Separate meters, parking layout, and trash enclosures often come up in plan check. We raise them early so the design does not change mid-permit.
Is this the right call for your project?
Call us for this when
- You own a rental property and want more doors on the same lot
- You want both units built at once to share the foundation and inspections
- You want the most rentable space out of the lot
Pick something else when
- One unit in the yard of your own home: a detached ADU
- The space is a garage: garage conversion
- You are not sure how many units your lot allows: start with the ADU builder overview
After the final inspection: keeping it in shape
- 1
Keep separate records per unit
Each unit has its own address, systems and appliances. Keep a folder for each.
- 2
Do not cut the fire wall
Mounting a TV or running a new line through the wall between units can break its rating. Ask first.
- 3
Walk each unit between tenants
Check plumbing, smoke alarms and windows at every turnover.
Recent work from our crews




More on our Instagram, where we post each stage as it happens.
Part of our ADU builder work. Related: garage conversion, detached ADU, above-garage ADU. Back to the J.O. Construction home page.
Thank you Jimmy for taking on our project for our ADU build. It was a pleasure from beginning to end to work with you guys. Always very transparent and there to answer any phone calls or questions.
ADU 730sf in Fontana, two bedrooms two bathrooms, complete kitchen. … Provided a good service and choices with the option of getting upgrades. Communication was key and Jimmy made it easy to reach out and listen to concerns or changes.
Multi-Family ADU questions from Chino owners
How many ADUs can I add to a multi-family property in California?
California law allows detached ADUs on a multi-family lot and lets owners convert non-living space into more. The count depends on the property, so we confirm it with the city for your address.
Can both units be built at once?
Yes. Building both units of a duplex ADU at once shares the foundation work, framing and inspections.
More doors on the same lot.
Send the address and what is on it today.
Mon to Fri, 7 AM to 5 PM

Thinking about a project? Let's talk.
Answer a few quick questions and Jimmy will call you back to talk it through. No pressure and no obligation.
- Jimmy runs your job from the first call to the final inspection
- Licensed and bonded, CA #1057456
- Design, permits and construction under one roof
Rather just talk to someone? Call (951) 436-6568
Mon to Fri, 7 AM to 5 PM