Build a Legal ADU or In-Law Suite in Southern New Hampshire

New state rules make it easier than ever to add an Accessory Dwelling Unit (ADU) to your property. Whether you’re creating space for family or planning for rental income, Beanstalk Home Improvements can help you design and build it the right way.

​

What Is an ADU?

An Accessory Dwelling Unit (ADU) — also called an in-law apartment, carriage house, or guest suite — is a secondary living space on the same property as your main home.

ADUs can take many forms:
• Attached: basement or garage conversions
• Detached: small cottage or backyard apartment
• Internal: finished attic, over-garage suite, or connected addition

They provide independence and flexibility without leaving home.

​

Why Add an ADU?

Homeowners across Southern NH are turning to ADUs to:
• Keep aging parents or adult children close to home
• Create a rental for extra monthly income
• Add flexible space for guests or a home office
• Increase property value without moving

Thanks to NH’s updated ADU law, most single-family homeowners can now add one “by right,” meaning towns must allow it as long as safety and zoning codes are met.

​

Our Step-by-Step Process

1️⃣ Site Review – We assess your property layout, zoning, and utilities.
2️⃣ Design & Estimate – We help you plan layout and finishes that fit your budget.
3️⃣ Permitting – We handle drawings, code compliance, and local approvals.
4️⃣ Construction – Full build, from foundation to final finish.

Not sure what’s possible on your property? We’ll quickly tell you what your town allows and what’s realistic for your space.

​

Typical ADU Timeline & Investment Ranges

Every property is unique, but here’s what most homeowners in Southern NH can expect when adding a legal in-law suite or ADU:

• Basement or garage conversion — starting around $60,000
  Includes a full finished living area with bathroom or kitchenette, flooring, lighting, and insulation.

• Attached addition (in-law suite) — typically $90,000+
  Includes new construction, utilities, bedroom/living space, and a private bathroom or kitchenette.

• Detached new build (carriage house or backyard ADU) — often $120,000+
  Includes foundation, plumbing/electrical connections, full kitchen and bath, insulation, and complete interior finishes.

Final pricing depends on size, site access, and finishes. Utility connections — such as electrical upgrades or septic capacity — can also affect cost and feasibility. We’ll review all of that during your property assessment to give you a clear, accurate estimate.

​

See If Your Property Qualifies

Fill out the short form below and we’ll review your property info, zoning, and goals — then follow up with next steps.
No pressure, just straightforward guidance from a local, family-owned remodeling company.

→ Request Your Free ADU Consultation

​

Related Projects

Looking for larger additions or full new builds?
→ Explore Additions & New Construction →