ADU Builder in Riverside, CA

Whether you're creating a home for family, planning for rental income or making better use of your property, MDT brings your ADU to life through design, permitting and construction.

From detached ADUs to garage conversions and second-story units, our team manages the details so you can focus on what matters most.

MDT is a licensed general contractor (CSLB 1054266). We're the builder responsible for your ADU: foundation, framing, utilities, trades, inspections and final finishes. If you need design and permits first, we handle those too, with one experienced team guiding the process.

I already have approved plans.

Send them over. We review your plans and site conditions, then prepare a construction proposal to build it.

I have an idea, but no plans yet.

We start with Design, take it through plans and permits, then build.

Detached ADUs

Attached ADUs

Second-story ADUs

Junior ADUs (JADUs)

Garage conversions

We also help legalize existing unpermitted units.

A 500 sq. ft. one-bedroom, one-bath ADU with a matching 500 sq. ft. garage, built on a hillside lot in Norco. Our crew set the roof trusses by crane, and dual mini splits keep it comfortable year-round. Foundation to finishes took about 8 months.

A 364 sq. ft. garage in Riverside, converted into a fully finished guest house. It includes a full kitchen with premium appliances, a tiled shower, a washer and dryer, closet space, and room for a queen bed plus a pull-out sofa for extra guests.

1. Design, if you need it. We set the layout, goals and specifications.
2. Plans and permits. We coordinate drafting, engineering and city review.
3. Construction. We manage every trade and inspection through completion. Already have approved plans? You start here.

Every property is different. These are the biggest factors in what your ADU will cost to build:

Size and layout

Site conditions and access

Utility connections

Electrical capacity and panel upgrades

Foundation and structural needs

Interior finishes

Your city's permit requirements

We review these factors early so you can make informed decisions about your project before construction begins.

Family-owned, hands-on construction management, with leadership involved from planning through completion.

Licensed general contractor, CSLB 1054266.

We build what we design, so plans are drawn with construction in mind.

Experience with tough sites, like our Norco hillside build.

One experienced team guiding the process.

Can MDT build my ADU if I already have approved plans?

Yes. We review your plans and site conditions and prepare a construction proposal based on them.

Do I need plans before contacting MDT?

No. We work with homeowners who are just starting and those who are ready to build.

Do you handle ADU plans and permits?

Yes. If you don't have plans yet, we coordinate design, drafting, engineering and city review before construction.

Can you build an ADU on a sloped lot?

Yes. Our Norco ADU was built on a hillside, and we set the roof trusses by crane.

How long does ADU construction take?

It depends on size, site and your city's review time. Our Norco ADU took about 8 months from foundation to finishes. You'll get a timeline for your project before construction starts.

Can you legalize an existing unpermitted ADU or garage conversion?

Yes. We review what's there, plan what needs to change and take it through permitting. Every property and city is different, so we confirm what's possible for yours.

Tell us about your property and where you are in the process. Plans or no plans, we'll tell you the next step.