Accessory Dwelling Units, built for CT.
Connecticut's 2026 ADU rules opened the door for accessory dwelling units across most municipalities. Lagace Construction designs, permits, and builds them — attached, detached, or basement-converted.
A legal second dwelling on your property.
Whether for an aging parent, an adult child, a long-term renter, or a flexible guest space, an Accessory Dwelling Unit (ADU) gives you a separate living unit on your existing property. Connecticut's 2026 ADU laws made permitting much easier in most towns.
We design, engineer, permit, and build all three ADU types: attached additions with separate entrances, detached structures (garage-with-living-above or standalone cottages), and basement conversions with egress windows and full kitchens.
- Attached ADUs (in-law wings, second-floor units)
- Detached ADUs (cottages, garage-with-living-above)
- Basement ADU conversions with separate entrance
- Town zoning research and variance applications
- Septic and water service tie-ins
- Full code-compliant build — passes CO inspection
Recent Connecticut projects.
Book a free, no-pressure quote.
Pick a time that works for you. Scott or one of our project leads will visit your home, walk the project with you, and follow up with a clear written estimate — usually within 5 business days.
- On-site consultation, no obligation
- Line-itemized written estimate
- Real timelines and a real start date
- CT Licensed & Insured (Reg. HIC.0617594)
Tell us about your project. We'll call you back within 1 business day.
Skip the back-and-forth. Book a meeting directly on Scott's calendar.
Prefer to call? Reach Scott directly at (860) 933-2700 • CT Licensed & Insured (Reg. HIC.0617594)
Common questions.
What is an ADU?
An Accessory Dwelling Unit is a separate, fully-functional living unit on the same lot as a primary residence. ADUs include their own kitchen, bathroom, sleeping area, and (typically) a separate entrance. They're used for in-laws, adult children, rental income, or guest housing.
Are ADUs legal in my CT town?
As of 2026 Connecticut state law, most municipalities must allow at least one ADU per single-family lot, subject to zoning. Some towns allow detached ADUs by-right; others require a special permit. We research your specific town's rules during the initial consultation.
How much does an ADU cost to build?
Basement ADU conversions run $80,000-$150,000. Attached ADU additions run $150,000-$300,000. Detached new-build ADUs (300-800 sq ft) run $200,000-$450,000. Pricing varies with utilities, septic, and finish level.
How long does an ADU project take?
Basement conversions: 12-16 weeks. Attached additions: 4-6 months. Detached new-builds: 6-9 months. Town permitting can add 4-12 weeks at the front depending on your municipality.
Hartford & Tolland Counties
Based in Andover, CT — building, remodeling, and adding on to homes across central and eastern Connecticut for over two decades.
Considering an ADU? Let's talk feasibility.
Free on-site visit. We'll review your lot, your town's zoning, and what kind of ADU makes financial and lifestyle sense.
CALL DIRECT(860) 933-2700