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Turn a Room Inside Your Home Into a Junior ADU in Sacramento
You may have a room you never use. It could be a large bedroom, an old den, or an attached garage. That room can become a small, private home. This type of unit is called a Junior ADU, or JADU for short.
A JADU lives fully inside your existing house. It cannot go bigger than 500 square feet. Next, it costs much less than building a new backyard cottage. That is because your roof, walls, and floor are already there. You do not need a new foundation or new framing from the ground up.
ADU Contractors Sacramento walks you through every part of the process. We draw the plans, pull the permits, and do the build. Also, we handle the plumbing, wiring, and city inspections. You work with one team from day one to move-in day.
Which Room in Your House Works Best for a JADU?
The right space depends on what your house already has. We convert four common types of interior spaces into junior units.
Attached Garage Interior Conversions
Many Sacramento homes have an attached two-car garage. That garage shares a wall with your living room or kitchen. Converting it is a fast path to adding 400 to 500 square feet of living space without touching the yard.
Concrete garage floors hold moisture underneath. Over time, that moisture damages any flooring placed on top. To stop this, we install polyethylene vapor barrier sheeting directly over the slab. Next, we confirm the floor is dry by testing it with a handheld concrete moisture vapor dome. This instrument measures the vapor pressure rising from the concrete pad before we cover it. This step satisfies CRC Section R506.2.3, which requires a vapor retarder under all new habitable concrete floor slabs.
Master Suite Conversions
A large master bedroom with a sitting room or extra closet space can become its own JADU. We close off the interior hallway door. Also, we add a small kitchenette along one wall.
That new kitchen needs dedicated electrical circuits so the outlets do not overload. We run 12-gauge non-metallic sheathed cable through the wall cavities to feed those circuits. Before we connect anything, we trace the existing wire paths in the wall using a handheld circuit tracer receiver. This device picks up the signal of live wires and shows us exactly where they run. This wiring plan satisfies CEC Article 210, which sets the branch circuit rules for all residential kitchen areas.
Den and Formal Dining Room Conversions
Some homes have a formal dining room that nobody uses, or a rear den that sits empty. These rooms are ready-made for a JADU because the floors and ceilings are already finished.
We build partition walls to close off the space and give it a private entrance. To anchor those walls, we snap steel drywall tracks to the slab. Next, we fasten the track down using a piston-drive anchor setting tool. This tool fires a powder-charged pin through the steel and into the concrete below. This connection satisfies CRC Section R602.3, which governs the fastening standards for metal and wood framing members.
Basement and Attic Space Conversions
Walk-out basements and tall attics add usable square footage below or above the main living floor. We can convert both into a JADU, provided the ceiling height meets code.
These spaces need insulation to stay comfortable year-round. We line the walls with extruded polystyrene rigid foam insulation board. Then we check the ceiling framing for level using a laser ceiling grid leveler. This tool casts a flat beam across the room to reveal any sag or tilt in the framing. This makes sure the finished ceiling hits the minimum clearance. This step satisfies CRC Section R305.1, which sets the seven-foot minimum ceiling height for all habitable rooms.
Four Ways a Junior ADU Project Is Different Here
Not every ADU contractor handles interior conversions. Here is what separates our process from the rest.
We Visit Your Home Before We Promise Anything
We walk through your rooms in person. We look at your walls, floors, ceilings, and plumbing stack. This tells us what the project will actually take before we give you a number.
Our Permit Drawings Are Done In-House
We do not send your plans out to a third-party designer. Our team draws the permit documents here. This cuts turnaround time and keeps your project from sitting still.
We Stay Involved Through the Entire Build
You deal with the same project lead from the first site visit to the final inspection. No handoffs. No new people showing up who do not know your project.
We Do Not Change the Price After We Start
Your written estimate includes every line item. That number does not go up mid-build because we uncovered something we should have found at the start.
The Four Steps We Take on Every Junior ADU Build
We run every JADU project in the same order. This keeps the work moving and avoids surprises.
STEP 01
Outside Wall for the Private Door
We cut the new entrance into the exterior of your home so the unit stands on its own from day one.
STEP 02
Kitchenette Plumbing
We tap into your main house’s water and drain lines and run new pipes to the JADU sink.
STEP 03
Run Dedicated Electrical Wiring
We pull new wires from your home panel to power the kitchen and climate system.
STEP 04
Hang the Fire-Rated Drywall
We board the shared wall between the JADU and your home to meet fire code.
See What Your Spare Room Can Become
We give you a free in-home review before we ask you to commit to anything. We measure your rooms, check your electrical panel, and trace the plumbing lines. By the time we leave, you will know exactly what your JADU will look like and what it will cost.
No pressure. No mystery pricing. Just a clear plan from a team that builds these every week across Sacramento.
Eight Questions Sacramento Homeowners Ask About JADUs
What is the largest a JADU can be in Sacramento?
A JADU cannot go above 500 square feet. It must be built entirely within the walls of your existing home or an attached garage. It cannot extend into a new footprint.
Does a JADU need solar panels?
No. Solar panels are required for new standalone structures in California. A JADU reuses your existing building envelope, so the solar requirement does not apply.
Can my JADU share a bathroom with the main house?
Yes. California specifically allows JADUs to share a bathroom with the primary home. Many owners add a private bathroom anyway to attract better tenants.
Does a JADU need its own SMUD meter?
No. A JADU is not treated as a separate utility account. It shares your home’s existing electrical, water, and sewer service. This alone saves several thousand dollars in connection fees.
What is the owner-occupancy rule?
The property owner must live on the lot at all times. You can live in the JADU while renting the main house, or live in the main house while renting the JADU. You cannot rent out both units at the same time.
Can I have a detached ADU and a JADU on the same lot?
Yes. California law allows one JADU inside the home and one detached ADU in the backyard on the same lot. Both must meet local zoning rules.
How is a JADU different from an attached ADU?
An attached ADU is an addition built onto the outside of your home. A JADU stays inside the existing walls. Also, an attached ADU can be up to 1,200 square feet, while a JADU is capped at 500.
How long does the full project take?
Permit drawings and city review usually take four to eight weeks. Construction runs two to four months after the permit is approved. Most clients are move-in ready within five to six months from our first visit.