ADU Builder in Colchester, CT | Accessory Dwelling Units

ADU Builder in Colchester, CT | Accessory Dwelling Units

Thinking about adding an accessory dwelling unit (ADU) to your property in Colchester, Connecticut? Lagace Construction specializes in ADU design and construction across eastern CT — from basement conversions and garage apartments to full in-law suite additions. We handle everything: permits, engineering, construction, and final inspection.

Colchester is a growing suburban community in New London County with a mix of established neighborhoods and newer subdivisions on lots ranging from half an acre to two acres, and a housing stock that spans everything from older ranches and capes to contemporary colonials. The town has seen steady population growth as Hartford-area commuters discover its combination of affordable housing and rural atmosphere, and that growth is driving demand for ADU rental units and in-law suites.

What Is an ADU — and Why Colchester Homeowners Are Building Them

An accessory dwelling unit is a secondary living space on the same property as your primary home. In Connecticut, ADUs are now permitted by right on most single-family lots under Public Act 21-29, which requires municipalities to allow at least one ADU per residential parcel. Colchester homeowners are using ADUs to:

  • House aging parents or adult children — the classic “in-law suite”
  • Generate rental income from a legal, permitted unit
  • Add long-term property value
  • Create a home office or studio with a full bath and kitchenette
  • Provide housing for a caregiver

ADU Types We Build in Colchester, CT

  • Basement ADU Conversion — Convert an unfinished basement into a legal dwelling unit with egress, kitchen, bath, and bedroom
  • Attached In-Law Suite Addition — Add a ground-floor suite connected to the main house — private entrance, full bath, kitchenette
  • Detached ADU / Backyard Cottage — Standalone structure on your lot, fully independent living space
  • Garage Conversion ADU — Convert an attached or detached garage into a finished living unit
  • Second-Story Addition ADU — Add living space above an existing garage or wing

Connecticut ADU Law — What Colchester Homeowners Need to Know

Connecticut Public Act 21-29 (effective 2021) requires all municipalities to allow at least one ADU on any residential lot that contains a single-family home. Colchester must permit ADUs by right — meaning you don’t need a variance or special exception, just a building permit through the local building department.

Key CT ADU rules:

  • ADU can be up to 30% of the primary home’s square footage or 1,000 sq ft — whichever is smaller
  • Owner-occupancy is required (you must live on the property)
  • Setbacks and lot coverage rules still apply per local zoning
  • Full building permit required — Lagace Construction pulls all permits and manages all inspections

How Much Does an ADU Cost in Colchester, CT?

ADU costs vary by type and finish level:

  • Basement ADU conversion: $60,000–$120,000 depending on existing conditions, egress requirements, and finishes
  • Attached addition ADU: $130,000–$220,000 depending on size and foundation type
  • Detached backyard ADU: $150,000–$280,000 for a full standalone structure
  • Garage conversion: $50,000–$100,000 depending on insulation, HVAC, and plumbing needs

We provide a free on-site estimate with line-item pricing — no vague ranges, no surprises. Call (860) 933-2700 or request an estimate online.

Why Colchester Homeowners Choose Lagace Construction for ADUs

  • CT Licensed & Insured — NHC #NHC-0016939, Electrical #E1-00191661
  • 25+ years of residential construction in New London County and eastern CT
  • 4.9 stars on Google — 40+ verified reviews
  • We pull all permits, manage all town inspections, coordinate electrical and plumbing subs
  • In-house carpentry crew — not a general who subs out every trade
  • Written estimates with real timelines before you sign anything

Frequently Asked Questions — ADU in Colchester, CT

Do I need a special permit to build an ADU in Colchester, CT?

You need a standard building permit — not a special use permit or variance. Under CT Public Act 21-29, Colchester must allow ADUs by right on single-family residential lots. Lagace Construction handles the entire permit process, including any required engineering drawings and town inspections.

Can I rent out an ADU in Colchester?

Yes — but you must live on the property as the primary owner-occupant. A permitted ADU in Colchester can be legally rented as a long-term rental. Short-term rental rules (Airbnb, VRBO) vary by local ordinance — we recommend checking with Colchester’s zoning office before marketing it as short-term.

How long does it take to build an ADU in Colchester?

From permit application to final occupancy certificate: typically 4–8 months for a basement conversion or attached addition, and 6–10 months for a detached structure. Permit approval timelines vary by town. We’ll give you a realistic schedule before any work begins.

Does an ADU add value to my home in Colchester?

Yes — consistently. A permitted, professionally built ADU typically adds $80,000–$200,000+ to a home’s market value in Connecticut, depending on size, type, and finish level. It also makes your property more attractive to buyers who want multigenerational living or rental income.

Ready to Build Your ADU in Colchester?

Call Scott directly at (860) 933-2700 or book a $175 ADU feasibility consultation — we’ll assess your property, walk through your options, and tell you exactly what’s possible under current CT zoning law. No pressure, no obligation.

Lagace Construction LLC
CT Licensed & Insured | ADU Builder serving Colchester, CT
(860) 933-2700 | lagaceconstruction.com
Author of The ADU Playbook — available on Amazon