Custom ADU & Detached In-Law Apartment Builder in CT

Unlock the full potential of your property with a standalone Accessory Dwelling Unit (ADU). Perfect for multi-generational living, a private home office, or a high-value rental unit.

Start Your ADU Build

From site preparation and utility trenching to final finishes, we handle the entire detached build process. Schedule your free estimate today.

Call (860) 933-2700

Custom Accessory Dwelling Unit (ADU) Solutions in Connecticut

As a leading ADU builder in Connecticut, Lagace Construction helps homeowners unlock the true potential of their property. Standalone Accessory Dwelling Units are the ultimate modern solution for families seeking a balance of close proximity and total privacy.

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Zoning Experts

We navigate the 2026 CT ADU regulations in towns like Hebron and Coventry for you.

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Utility Integration

From septic extensions to utility trenching, we handle the complex infrastructure detached builds require.

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Premium Finishes

Our ADUs feature the same high-end craftsmanship as our New Home Builds.

ADU Builder Connecticut - New concrete foundation for a detached in-law cottage in Coventry

The Technical Side of Building Detached

Building a detached ADU is essentially building a custom tiny home. It requires its own dedicated slab or frost-wall foundation, independent electrical sub-panels, and often specialized plumbing pumps if the topography doesn't allow for gravity-fed drainage to the existing septic system.

As a specialist ADU builder in Connecticut, Scott Lagace manages the heavy site work—including utility trenching and land clearing—to ensure your new unit functions perfectly without straining your main home's resources. Explore our home additions for attached options.

Trusted by Your Neighbors

With over 24 years of excellence in Tolland County and across Northeast Connecticut, we bring "Big Builder" standards to your custom backyard project.

Structural framing by an ADU Builder in Connecticut for an in-law expansion

Strategic Multi-Generational Living

A standalone unit provides more than just extra space; it offers a long-term strategy for multi-generational living and estate planning. By creating a detached "in-law cottage," you can house elderly parents while maintaining the quiet enjoyment of your primary home.

This increase in property utility also significantly boosts home equity. As an experienced ADU builder in Connecticut, we help you weigh the pros and cons of building detached versus Attached In-Law Suites or building "up" with a second floor expansion.

ADU & Backyard Cottage FAQs

What is the difference between an In-Law Suite and an ADU?
In Connecticut, an In-Law Suite usually refers to an addition attached to the main house or a basement conversion. An ADU (Accessory Dwelling Unit) is typically a standalone, detached structure (like a backyard cottage) that includes its own kitchen, bathroom, and entrance.
Are ADUs legal in my Connecticut town?
As of 2021, a statewide law in Connecticut made ADUs legal in most residential zones. However, specific requirements for setbacks, height, and square footage vary between towns like Hebron, Coventry, and Andover. We handle the zoning and permit verification process for you.
How much does it cost to build an ADU in CT?
A detached ADU is essentially building a custom "tiny home." Most projects range from $150 to $300+ per square foot. This includes site preparation, foundation, utility trenching, and high-end interior finishes.
Do I need separate utilities for a detached ADU?
Typically, yes. We manage the process of trenching and extending plumbing, electrical, and HVAC lines from your primary residence to the ADU. We also ensure your existing septic system or sewer connection is sufficient for the added load.
How long does the construction process take?
Since an ADU is a standalone building, the timeline is similar to New Home Construction, usually taking 12 to 20 weeks from the time permits are issued. This accounts for excavation, structural framing, and full interior build-outs.
Will an ADU increase my property value?
Yes. Adding a permitted secondary dwelling is one of the most effective ways to build long-term home equity. It adds versatile square footage that can be used for multi-generational living, a home office, or a legal rental unit.