ADU Builders in New Jersey
Garden State ADU is a licensed New Jersey home improvement contractor (NJ HIC #13VH13918800). We build accessory dwelling units, in-law suites and conversions in Central Jersey, and for the rest of the state we match homeowners with an ADU builder who works in their area.
- We build inWe build in
- 4 counties4 Central NJ counties
- ElsewhereEverywhere else
- A partnerA partner builder
- First stepFirst step
- Your zoningYour zoning
A second, separate home on your lot.
It is tempting to hire an ADU contractor and let them worry about the rules. In New Jersey that is a risk, because there is no statewide ADU law here. Each of the state's municipalities writes its own zoning ordinance, and the answers are far apart. A few towns permit an accessory dwelling unit on an ordinary residential lot. Some permit only a suite for a family member. Many have written nothing at all, which usually means a detached backyard unit needs a variance from the zoning board.
So the useful question is not only who builds ADUs near you. It is what your town will let you build, and then who builds that. A builder can give you a fair price for a detached cottage that your zoning board will never approve. We would rather you knew the answer before you paid for plans.
Before you hire anyone, know
- Whether your town permits an ADU at all
- Whether it may be detached from the house
- Which zones the ordinance covers
- The size cap, owner-occupancy and parking rules
When the answer is not a detached ADU
An in-law suite addition
With its own entrance, and part of one legal residence.
A mother-daughter arrangement
In the towns whose code provides for one.
A garage conversion or a finished basement
Living space from a structure you already have.
Who asks us about an ADU.
Room for a parent or an adult child
Most of the people who write to us want room for a parent or an adult child, and most of them live in a town with no ADU ordinance.
Owners in a town that permits one
Where the ordinance allows a second unit, it sets the terms: zones, size, owner-occupancy and parking.
Owners with a unit already there
If a second unit already exists on your property without paperwork, the question is different.
If you want to know what your town allows before you call anyone, send us your address for a free zoning check and written estimate.
ADU builders by region, and what each town allows.
These are the towns we have written up so far. Each link goes to that town's page, with the ordinance, the conditions and the questions people ask most. If your town is not listed, the free check still covers it. Our town-by-town guide to New Jersey ADU rules shows what we have verified so far.
Central Jersey
This is where we build ourselves: Middlesex, Mercer, Monmouth and Somerset counties. If your lot is here, the company that reads your zoning is the company that builds the project.
| Town | What the code says | Status |
|---|---|---|
| Princeton Mercer County | Permitted by-right. Read the Princeton rules. | Permitted by-right |
| Trenton Mercer County | Ordinance on the books, approval route unconfirmed. Read the Trenton rules. | Approval route not confirmed |
| Lawrence Township Mercer County | Permitted with conditions. Read the Lawrence Township rules. | Family suite provision |
| Red Bank Monmouth County | Permitted by-right. Read the Red Bank rules. | Permitted by-right |
| Middletown Monmouth County | Permitted with conditions. Read the Middletown rules. | Family suite provision |
North Jersey
Most of the towns in our guide that have written an ADU ordinance are here, in Essex, Hudson, Bergen and Union counties. We run the zoning check, then match you with a builder who works in your county.
| Town | What the code says | Status |
|---|---|---|
| Jersey City Hudson County | Permitted by-right. Read the Jersey City rules. | Permitted by-right |
| Maplewood Essex County | Permitted by-right. Read the Maplewood rules. | Permitted by-right |
| Montclair Essex County | Permitted by-right. Read the Montclair rules. | Permitted by-right |
| South Orange Essex County | Permitted by-right. Read the South Orange rules. | Permitted by-right |
| Teaneck Bergen County | Permitted by-right. Read the Teaneck rules. | Permitted by-right |
| Union Township Union County | Permitted with conditions. Read the Union Township rules. | Permitted with conditions |
| East Orange Essex County | Permitted with conditions. Read the East Orange rules. | Permitted with conditions |
| Newark Essex County | Permitted with conditions. Read the Newark rules. | Permitted with conditions |
The Shore
The shore towns in our guide each attach their own conditions, such as two extra off-street parking spaces in Bradley Beach and no short-term rentals in Asbury Park. We check the ordinance first, then match you with a builder who works at the shore.
| Town | What the code says | Status |
|---|---|---|
| Asbury Park Monmouth County | Permitted by-right. Read the Asbury Park rules. | Permitted by-right |
| Bradley Beach Monmouth County | Permitted with conditions. Read the Bradley Beach rules. | Permitted with conditions |
| Cape May Cape May County | Permitted with conditions. Read the Cape May rules. | Affordable-housing program only |
What to check before you hire any ADU builder in New Jersey.
A registration number you can look up
New Jersey's Contractor's Registration Act requires home improvement contractors to register with the Division of Consumer Affairs and display their registration number. Ask for it before anything else, and look it up yourself. Ours is on every page of this site.
Who applies for the construction permit
Under the state's Uniform Construction Code, a permit has to be issued before the work starts. Ask who is filing the application and whose name goes on it. A builder who suggests skipping the permit is telling you how the rest of the job will go.
A zoning answer before any design money
Whether you may build a second unit at all is a zoning question, and it comes before floor plans. If a builder wants a design deposit before anyone has read your town's ordinance against your lot, you are paying to find out something that could have been checked first.
A written scope and a written price
The contract should say what is being built, what is not included, and what the payment schedule is tied to. Site work, utility connections and permit fees are the items that most often turn out to be missing.
How the match works outside our four counties
If your lot is anywhere else in New Jersey, we introduce you to a builder who works in your area, and we pass along the zoning read so you do not start from zero with them. We are plain about the business side. When we match you with a builder outside our area, we share your project details with that builder so they can contact you, as our privacy policy describes. You do not pay us for the zoning check or for the introduction. The builder may pay us a referral fee if you hire them, and that does not change what you pay the builder.
What it costs.
Your written estimate gives the real number.
An ADU's cost turns on whether it is detached or attached, its size, the site work and how far the utilities have to run, and on what your town requires. The site visit and written estimate are free. If the answer for your lot is a family suite rather than a separate cottage, see in-law suite additions or the garage apartment option.
How the job runs.
Osama, who owns the company, reaches out to you personally, by phone or text. This is where the lot itself comes in: your zone, your setbacks, what already sits on the property. If your lot is in Middlesex, Mercer, Monmouth or Somerset County, we can design, permit and build it ourselves.
- 01Call or send the formFREE
- 02We check your zoningFREE
- 03Site visit and written estimateFREE
- 04Design
- 05Approvals and permits
- 06The build
- 07Final inspection
Design & Permit agreement first
A paid Design & Permit agreement for a flat fee, credited toward the build if you sign the construction contract within 60 days. It covers the zoning research, drawings by our partner architect, survey coordination, the permit or variance application, and a detailed construction budget. The drawings are yours to keep.
Questions about hiring an ADU builder in New Jersey.
Do you build ADUs everywhere in New Jersey?
No. We build in Central Jersey ourselves, which means Middlesex, Mercer, Monmouth and Somerset counties. Everywhere else in the state we still run your zoning check, and then we match you with a builder who works in your area. We say which one applies to you in our first reply.
How is this different from a contractor directory?
A directory lists builders near your ZIP code. It does not tell you whether your town allows the project. We start from your town's ordinance, so you find out whether a detached ADU, an attached in-law suite or an addition is the realistic path before you talk to any builder. Most New Jersey towns have no ADU ordinance, so that first answer changes what you should ask a builder to price.
What does the zoning check cost?
Nothing. You send your ZIP and what you want to build, we read what your municipality's code says, and Osama reaches out to you personally, by phone or text, with what it allows.
Will you share my information with a builder?
Only to make the match. If your project is outside the area where we build, we share your project details with a builder who works in your area so they can contact you. Our privacy policy describes this. If you would rather we did not, say so in your reply and we will keep the zoning check between us.
Does my town even allow an ADU?
It depends on the municipality, because New Jersey has no statewide ADU law and each town writes its own zoning. A small number of towns permit ADUs, some permit a family-only suite, and many have written nothing, which usually means a detached unit needs a variance. Our town-by-town guide lists what we have verified, and the free check covers your specific address.
What if my town does not allow a detached ADU?
Then the project usually changes shape instead of ending. An attached in-law suite, an addition, a garage conversion or a finished basement stays part of one legal residence, and that is a permitted path in far more towns than a separate backyard unit.
Start with what your town allows.
The estimate is free and so is the site visit. Free zoning check on your address, then a builder who works where you live.
- 01Osama reaches out to you personally, by phone or text.
- 02We check your town's zoning for your address.
- 03We walk the property and measure.
- 04You get a written estimate. No obligation.