Modular ADUs, Built Around Your Life
CT ADU is a Fairfield County–based company that designs and builds detached accessory dwelling units—mostly modular through factory partners, with site-built options when the property or your plans call for it. Learn more about CT ADU and the team behind your project.
- Based in Darien, CT
- Serving Fairfield County
- 9 detached models, 543–940 sq ft
- Modular or site-built
What can a backyard ADU be used for?
Most Fairfield County homeowners build an ADU for family, for rental income, or for flexible space like a home office.
Housing for family
Warmth and privacy for in-laws, guests, or a growing family — close enough to care, private enough to thrive.
Rental income
Where your town allows it, a rented ADU can help offset your mortgage.
Added value
A smart long-term investment in equity and appeal — adding livable square footage buyers actively seek.
Why Fairfield County homeowners build with CT ADU
Modular, or site-built when needed
Most of our ADUs are built off-site by factory partners for tighter quality control and less disruption at home. When a lot or a plan needs it, site-built construction is also an option.
Modular vs. site-built ADUsPermitting assistance
We provide hands-on permitting assistance — coordinating zoning and building applications and guiding you through your town's specific requirements.
How Connecticut ADU rules workFinancing, explained
Compare HELOCs, renovation lines and other ways homeowners fund an ADU, with plain-English pros and cons.
ADU financing optionsDetached ADU floor plans from 543 to 940 sq ft
Nine customizable models with one or two bedrooms. Four show a sample accessible plan, and accessible features can be designed into the others too.
Our models are named for Fairfield County places, but any model can be built in any town where the zoning and lot allow it.
Can you build an ADU in Connecticut?
ADU eligibility depends on your property and the state and local rules that apply. Connecticut’s 2021 law, Public Act 21-29 (CGS §8-2o, as amended), established a statewide ADU framework and allowed towns to opt out before 2023. Zoning, setbacks, septic or sewer capacity, and other site and code requirements determine what’s possible.
Read our Connecticut ADU guideHow the ADU process works
Seven steps, from a first conversation and a zoning review through permits, factory build, delivery and move-in.
See all seven stepsWhere we build in Fairfield County
CT ADU is based at 30 Old Kings Highway S in Darien and works with homeowners across Fairfield County, including Bethel, Bridgeport, Brookfield, Danbury, Darien, Easton, Fairfield, Greenwich, Monroe, New Canaan, New Fairfield, Newtown, Norwalk, Redding, Ridgefield, Shelton, Sherman, Stamford, Stratford, Trumbull, Weston, Westport, Wilton.
Have a property outside Fairfield County? Contact us to discuss your plans and potential delivery options.
Common questions about building with CT ADU
What does CT ADU do?
Based in Fairfield County, Connecticut, CT ADU designs and builds accessory dwelling units. We help homeowners work through property feasibility, design, permitting and construction.
Where does CT ADU build?
CT ADU is based in Darien and serves homeowners across Fairfield County, Connecticut. Have a property in another county? Contact us to discuss your plans and potential delivery options. Whether an ADU can be built on your property depends on state and local rules and on site conditions.
Does CT ADU only build modular ADUs?
No. Most of our ADUs are modular, built off-site by factory partners. When a lot or plan calls for it, site-built construction is also an option.
What happens in a free feasibility review?
Share your property address and goals through our questionnaire. We review zoning, setbacks and septic or sewer considerations to help identify what needs further investigation before you spend on design. This review is preliminary: it isn't a permit approval or a guarantee that an ADU can be built on your property.
Do I need to choose a model before contacting you?
No. Start with your property and what you want the ADU to do. We can help you compare layouts as we review your goals and site constraints.
Can CT ADU help me figure out how to pay for an ADU?
Yes. Our guides and calculators explain ways to pay for an ADU, and we can introduce you to vetted third-party lenders if you'd like. Start with our financing guide. CT ADU isn't a lender and isn't paid by lenders. Introductions are optional.
