ADU Builder in Barnstable County, MA
Mussato Building Group designs, permits, and builds ADUs in Barnstable County, MA, from detached guest cottages to in-law suites and garage conversions. We are a family-owned general contractor founded in 2004, with more than 100 projects completed and a 5.0 rating from 21 Google reviews. We are based in South Yarmouth, in the middle of the Cape, so every town is within about an hour, and we work across all 15 towns: Barnstable, Bourne, Brewster, Chatham, Dennis, Eastham, Falmouth, Harwich, Mashpee, Orleans, Provincetown, Sandwich, Truro, Wellfleet, and Yarmouth.
- Family-owned since 2004
- Licensed + insured in MA
- 100+ projects completed
- 5.0 stars from 21 Google reviews
- BBB accredited
Building an ADU in Barnstable County
Barnstable County is Cape Cod: 15 towns, from Bourne and Falmouth at the canal to Provincetown at the tip, each with its own building department, board of health, and conservation commission.
State law allows one ADU of up to 900 square feet by right on most single-family lots, and that includes Barnstable County. What usually decides the project here is the lot and the septic system: an ADU with a bedroom adds to the bedroom count the system has to carry under Title 5, so we start with your town’s Board of Health.
In the Old King’s Highway district of Barnstable County along Route 6A, a detached ADU that can be seen from the street also needs a certificate from the OKH committee, so we design the cottage to fit the historic houses around it.
Inside the Seashore district of Barnstable County, zoning limits new structures more than elsewhere in town, so whether an ADU fits on a Seashore lot is the first thing we confirm.
In a town with many summer homes, an ADU often becomes the guest cottage that lets family visit Barnstable County without crowding the main house.
“As the General Manager of Pretty Picky Properties I’ve had the pleasure of working with Joe and his team for nearly 10 years. Joe’s carpentry skills are unmatched. He’s always respectful, finishes on time, priced well, and transparent from start to finish. You will not regret hiring Mussato Building Group.”
ADU permits in Barnstable County
We prepare the drawings, file the applications, and schedule the inspections. Here is what a project like this usually needs:
- Building permit from your town’s Building Department, and a certificate of occupancy at the end.
- Review by your town’s Board of Health of septic capacity under Title 5 if the ADU adds a bedroom.
- Zoning review of setbacks, height, and lot coverage under your town’s zoning bylaw.
- Conservation Commission review if the ADU is within 100 feet of a wetland, coastal bank, dune, or salt marsh.
- Flood-zone design if FEMA maps the lot in an AE or VE zone.
- A certificate from your town’s Old King’s Highway committee if the ADU can be seen from a public way in the historic district.
- Seashore district zoning review if the lot is inside the Cape Cod National Seashore.
- Detached ADUs and guest cottages
- Attached ADUs and in-law suites
- Garage and lower-level conversions
- Kitchens and bathrooms sized for small spaces
- Foundations, framing, and exteriors matched to the main house
- Heat, hot water, and electrical for a second dwelling
- Zoning, septic, and permit coordination
- Site work and paths between the houses
ADU Builder in Barnstable County: FAQ
Can I build an ADU in Barnstable County?
In most cases, yes. State law allows one ADU of up to 900 square feet, or half the size of the main house if that is smaller, by right on single-family lots in Barnstable County. Setbacks, septic capacity, Old King’s Highway review, and conservation rules still apply, so we check your lot first.
Which towns in Barnstable County do you build ADUs in?
All 15 of them: Barnstable, Bourne, Brewster, Chatham, Dennis, Eastham, Falmouth, Harwich, Mashpee, Orleans, Provincetown, Sandwich, Truro, Wellfleet, and Yarmouth. We are based in South Yarmouth, in the middle of the Cape, so every town is within about an hour.
Will my septic system handle an ADU in Barnstable County?
Most homes in Barnstable County are on septic systems, while parts of Hyannis, Falmouth, Chatham, Provincetown, and Bourne have town sewer. On septic, Title 5 sizes the system by bedroom count, so an ADU with a bedroom can mean a septic upgrade. Your town’s Board of Health reviews it before the building permit.
Can I rent out an ADU in Barnstable County?
Long-term rentals are allowed, and the town cannot require you to live on the property. Short-term rentals of an ADU can be restricted by the town, so check your town’s rules before you plan on summer rentals.
More in and around Barnstable County
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- Basement Remodeling in Barnstable County, MADated or damp finished basements rebuilt from the foundation in
- Basement Egress Windows in Barnstable County, MACode-size escape windows and window wells for basement bedrooms
- Bathroom Remodeling in Barnstable County, MATile showers, tubs, vanities, and powder rooms
- Kitchen Remodeling in Barnstable County, MALayouts, islands, custom cabinetry, and counters
- ADU Builder on Cape CodThe whole Cape, from Bourne to Provincetown
- The Massachusetts ADU Law: What the 900-Square-Foot Rule MeansGuide
- How Much Does an ADU Cost on Cape Cod?Guide
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