Detached ADU
A standalone structure, sometimes called a backyard cottage or guest house, separate from the main home. It needs its own foundation, framing, and utility connections, so it tends to be the largest of these projects.
// ADU Construction
Build your ADU with a contractor you choose.
An ADU, or accessory dwelling unit, is a second, self-contained living space on the same lot as your home, with its own kitchen, bath, and entrance. The contractors you see here are already licensed, insured, and vetted, so you pick the one you want and your request goes to that one. Free for homeowners.
Every contractor here is licensed, insured, and vetted before they're listed. You pick the one you want, and your request goes to that one.
Vetted Pros Only
What ADU construction covers
An ADU is a complete, independent home in miniature on your property. It can be built a few different ways, and the path you take depends on your lot and what you already have:
Attached ADU
An addition that shares a wall with your existing home. It ties into the structure you already have and can sometimes use utility connections that are already close by.
Garage conversion
Turning an attached or detached garage into a living space. It is the most common ADU because the shell already exists, though it still needs insulation, plumbing routed through the slab, and the garage opening framed in.
Interior conversion
Carving a unit out of existing space inside the home, usually a basement or attic. The work centers on safety: floor reinforcement, egress, soundproofing, and separate heating and cooling.
Junior ADU
A smaller unit, capped at 500 square feet, built inside the home with its own entrance and a compact kitchen. It can share a bathroom with the main house, and it often comes with an owner-occupancy rule.
Legalizing an existing unit
Bringing an older, unpermitted space up to code so it can be permitted, often after an inheritance or a code-enforcement notice.
// ADU Construction work by vetted pros
When people build an ADU, and what they ask first
Most ADU projects start with a change in the family. A parent needs a place of their own nearby. An adult child is moving back. Someone wants to age in the family home with help close at hand, or to stay on the property while renting out the larger house. Others build to bring in rental income. Whatever starts it, a handful of questions tend to come up first:
Question 01
What kind of ADU does my lot allow?
That depends on local zoning, setbacks, and the size of your home, and the rules vary a lot by city and state. A good contractor checks your specific jurisdiction before promising anything.
Question 02
Can I rent it out, or sell it separately later?
You can usually rent it. You generally cannot sell it on its own, because an ADU is tied to the main home and the lot, not a separate parcel.
Question 03
Will my existing utilities handle a second unit?
Sometimes, and sometimes not. An older electrical panel or a small water line may need upgrading to carry the added load, which is one of the bigger swing factors in the budget.
Question 04
Do I need a permit, and who pulls it?
Yes, ADUs are permitted work, and the contractor should pull the permit, not ask you to pull it in your name. A push to pull it yourself is a sign to slow down.
A vetted ADU contractor should welcome these questions and answer them straight. The vetting here checks the license, the insurance, and the standing up front, so the contractors you are choosing from can already speak to them.
What affects the cost
Two ADUs of the same size can land at very different numbers, and a few things explain most of the gap. The type matters first: a detached unit with its own foundation and utility trenching usually costs more than a garage or interior conversion that reuses an existing shell. Utilities are the quiet driver. If your electrical panel, water line, or sewer connection cannot carry a second unit, upgrading them adds real cost, and a backyard that slopes the wrong way can mean a pump system instead of a simple gravity sewer line. Access plays in too: a tight side yard that heavy equipment cannot reach pushes labor up. And the soft costs that homeowners often forget, the engineering, the soil testing, the permit and utility fees, regularly run a fifth to a third of the whole budget.
If you need a way to pay for the work, financing options are available through trusted lending partners. You choose what works for you, there is no pressure, and the platform stays free for homeowners.
How to choose an ADU contractor
An ADU is a small house, with structure, plumbing, electrical, and utility tie-ins all in one project, so the contractor you pick matters more than any single design choice. A few things are worth checking before you commit:
License and standing
Building an ADU usually calls for a general building contractor license, active and in the right classification. You can verify the license directly on your state's contractor licensing board, and confirm the name on the license matches the company you are talking to.
Insurance
General liability and workers' compensation protect you if something goes wrong on site. Ask to see current certificates.
The right specialty, where it counts
If you are building for an aging parent, some contractors hold an aging-in-place certification that shows training in features like zero-threshold entries and roll-in showers. It is not required, but it tells you something.
A clear contract and warranty
Scope, schedule, how changes are priced, and what is warranted and for how long, all in writing, with payments tied to milestones rather than a large sum up front.
// Warning signs When to keep looking
The warning signs are consistent.
- Watch for a contractor who pressures you to pull the permit yourself under owner-builder status, which shifts the legal and financial liability onto you.
- Watch for a large upfront payment demanded before any ground is broken.
- And ADUs have drawn a specific scam: out-of-state operators who set up a local-looking front, hand you a contract with a license number stolen from a real local builder, take a big deposit, then stall and disappear.
- You protect yourself by looking the contractor up on the state board yourself, confirming the address and phone on the state record match what the salesperson gave you, and calling your local building department to confirm a permit was actually filed under that contractor's name before you release money past the deposit.
// A platform, not a contractor
A shorter, safer list. The choice stays yours.
This is the part the platform is built to take off your plate. Our ADU contractors are vetted before they can join, by people who spent their careers in the trades and know how to judge a contractor's license, insurance, record, and work. We are a platform that connects you with contractors; the contractor owns the project and the relationship. You get a shorter, safer list, and the choice stays yours.
Start your project →Good to know before you start
A few terms and a couple of myths that come up on most ADU projects:
Soft costs
The engineering, soil testing, permit fees, and utility tap fees that come before any building starts. They are easy to forget and they regularly run a fifth to a third of the total, so a budget that counts only construction is usually short.
Owner-occupancy
Some ADU types, junior ADUs in particular, require the owner to live in either the main home or the unit. Whether that applies depends on your state and city.
You usually cannot sell an ADU on its own
People often assume a backyard ADU can be split off and sold separately. Under standard zoning it cannot; it stays tied to the main home and the lot.
A separate utility meter is not always required
Many homeowners think they have to pay for independent gas, water, and electric meters. In many places you can branch off the main home's lines instead and use a private submeter to track the unit's use, which avoids the larger municipal meter costs.
An ADU is usually invisible from the street
A common worry is that an ADU changes the look of the neighborhood. Most are garage conversions or backyard units set behind the main home, so they tend to be hard to see from the road.
// Vetted, licensed, insured
// Find a vetted contractor
Find a vetted ADU contractor near you
Every ADU contractor here is licensed, insured, and vetted before they're listed. You pick the one you want, and your request goes to that one. Your information is not sold to a list of companies who race to call you.
Start your project, choose your area, and see the vetted contractors near you.
Start your project →Common questions
Can I sell my ADU separately from my house?
Usually not. An ADU is tied to the main home and the lot, so under standard zoning it cannot be sold on its own. You can generally rent it out.
Do my utilities need to be upgraded for an ADU?
Sometimes. If your electrical panel, water line, or sewer connection cannot carry a second unit, it may need upgrading, and that is one of the larger swing factors in the cost. A contractor checks this for your specific property before quoting.
Who pulls the permit for an ADU?
The contractor doing the work should pull it. If a contractor pushes you to pull the permit yourself under owner-builder status, treat it as a warning sign, because it shifts the legal and financial liability onto you.
Is this free for me?
Yes. The platform is free for homeowners, always. You choose your contractor and connect with them directly.
Ready to start? Find your vetted contractor.
Start your project → FREE FOR HOMEOWNERS // YOU CHOOSE YOUR PRO