NH Seacoast

ADUs on the New Hampshire Seacoast

Name: NH ADU Experts
Address: 357 Route 108, Madbury, NH, 03823, US
Telephone: +16037078568
Price range: $184,000–$483,000

Our shop is in Madbury. We build across the Seacoast — Portsmouth, Dover, Durham, Exeter, Hampton, and the Strafford and coastal Rockingham towns around them — under the same statewide by-right rule as the rest of New Hampshire.

Under NH RSA 674:71-73 (HB 577, effective 2025-07-01), one accessory dwelling unit is allowed by-right on single-family lots statewide. Detached ADUs run up to 950 sf unless your town allows more. We publish all-in prices on 10 architect-designed models — $184,000–$483,000 — covering the base build, foundation, on-lot utility runs, permits, design, and standard finishes. Builds typically run 12–16 weeks after permits. Town water and sewer tap fees, and major site work, are quoted separately, in writing, before you sign.

Get a quote →See it on your lot NH ADU cost guide

Or call (603) 707-8568. Shop: 357 Route 108, Madbury, NH.

Towns in this area

Setbacks follow your lot's single-family rules. We verify the ordinance with your town before a price is final. Longer-distance projects may include a travel-time allowance — always confirmed up front in your quote.

Setback disclaimer. This is a to-scale preview, not a survey or permit — exact property lines aren't shown. We verify every setback, lot line, wetland buffer, and zoning rule directly with your town at your on-site assessment before any price is final.

Browse the 10 models → · The by-right law →