Do you build ADUs in Durham?

Yes. Langone Site Services builds turn-key ADUs in Durham, New Hampshire. The yard is 45 minutes away in West Newfield, Maine. 10 published models $155,000–$408,000.

Do you self-perform excavation and septic?

Yes. We own the excavation fleet and self-perform site work and septic. Conventional septic in Maine starts at $18,000. Maine design is $500. Specialty trades (plumbing, electrical) sit under one Langone prime contract.

Do you build custom homes in West Newfield and nearby towns?

Yes. New and custom homes start at $325/sq ft and go up from there. Land is not included. Site work and the house sit under one contract. We do not publish a four-tier price table.

Serving Durham

ADU Builder & Excavation Contractor in Durham, New Hampshire

Seacoast ADU builder for Durham lots near UNH and the bay. Based 45 minutes away in West Newfield, Maine. Turn-key ADUs, custom homes starting at $325/sq ft, excavation, and septic across Strafford County.

Excavation, septic installation, and site work in Durham. We own the fleet. Excavation contractor Maine. Septic installation Maine. Site work contractor, southern Maine.

Get instant pricing (978) 987-0089

45 min from HQ

Strafford County

Maine DEP Erosion Certified

Local Context

Why Durham is a strong market for ADU and excavation work.

Durham is a Seacoast town with Residence A lots close to campus and larger rural parcels out Route 4. We run it from West Newfield when the job is a full build, not a punch-list.

Setbacks

Front, side, and rear in Durham.

NH RSA 674:71-73 (HB 577) — one ADU by right on a single-family lot

Durham is UNH country and a Seacoast commute. Residence A is the district we see most for a backyard unit. Front setbacks tier by street class.

District	Front	Side	Rear	Lot / cover
RA · primary Residence A Table 175-54. Front 30 ft on minor/collector, 40 ft on arterial.	30 ft	10 ft	20 ft	20,000 sf · 33% impervious
RB Residence B	40 ft	20 ft	30 ft	40,000 sf · 30% impervious
R Rural	40 ft	50 ft	50 ft	150,000 sf · 20% impervious

One ADU by right. Setbacks match the house in that district.
Downtown form-based districts (CB1/CB2) use notes instead of a fixed front number. We do not print a fake number for those.

Verified 2026-07-05 against Durham zoning ordinance, Table 175-54. Towns amend ordinances. Confirm with the land-use office before you build. Official source

ADU Construction

ADU Builder in Durham

RA lots can take a backyard unit if the 30 / 10 / 20 setbacks clear. We match a published model to the leftover yard, we do not force The Ossipee onto a tight parcel. 10 published models $155,000–$408,000 on a standard site. See the ADU models.

See the 10 ADU models Price My ADU

Excavation & Site Work

Excavation Contractor in Durham

Grade and old fill show up near the village. We handle the pad, the trench, and the erosion controls under one contract.

All Site Services Free Site Review

Excavation contractor Maine Septic installation Maine Site work contractor, southern Maine

Septic installation in Durham

Septic installer York County and nearby NH. Maine design is $500. Conventional work starts at $18,000.

Septic installation Maine

Excavation contractor in Durham

Excavation contractor southern Maine and the NH Lakes / Seacoast. Land clearing and site prep. We own the fleet. Maine DEP Erosion Control Certified.

Excavation contractor Maine

Site work in Durham

Crewed and equipped in-house. Land clearing and site prep. We own the fleet. Driveways, foundations and drainage, utility trenching, and municipal and road work.

Site work contractor, southern Maine

Zoning & Permitting

What Durham actually allows.

Residence A setbacks are 30 ft front, 10 ft side, 20 ft rear. Rural is much larger. See the table.

Check My Lot

Also Serving

Neighboring towns we build in.

DoverMadburyLeeNewmarket

Full service area is about an hour from West Newfield, ME. See the full service area map.

Sanford, ME Kennebunk, ME Wells, ME Waterboro, ME Rochester, NH Dover, NH Wakefield, NH Wolfeboro, NH Ossipee, NH Newfield, ME Alton, NH Laconia, NH

FAQ

Building in Durham.

Do you build ADUs in Durham?: Yes. Langone Site Services builds turn-key ADUs in Durham, New Hampshire. The yard is 45 minutes away in West Newfield, Maine. 10 published models $155,000–$408,000.
Do you self-perform excavation and septic?: Yes. We own the excavation fleet and self-perform site work and septic. Conventional septic in Maine starts at $18,000. Maine design is $500. Specialty trades (plumbing, electrical) sit under one Langone prime contract.
Do you build custom homes in West Newfield and nearby towns?: Yes. New and custom homes start at $325/sq ft and go up from there. Land is not included. Site work and the house sit under one contract. We do not publish a four-tier price table.

Start your project

Ready to build in Durham?

Free consultation, real pricing, permitting handled. Recent work: Seacoast ADU feasibility in Durham.

Book Free Consult (978) 987-0089

Or email dylan@langonesiteservices.com