ADU Builder in Chatham, MA
Mussato Building Group designs, permits, and builds ADUs in Chatham, 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. Our base in South Yarmouth is about 13 miles away, and we work across Chatham Village, North Chatham, South Chatham, West Chatham, and Chathamport.
- Family-owned since 2004
- Licensed + insured in MA
- 100+ projects completed
- 5.0 stars from 21 Google reviews
- BBB accredited
Building an ADU in Chatham
Chatham sits at the elbow of the Cape, surrounded by water on three sides, with shingled capes and summer cottages from its fishing-village past.
State law allows one ADU of up to 900 square feet by right on most single-family lots, and that includes Chatham. 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 the Chatham Board of Health.
Where a property is historic, we check with Chatham’s Historical Commission before the design is final.
In Chatham, our work includes the restoration of a 1904 cottage overlooking Chatham Light, which received a 2022 Chatham Preservation Award, and a modern coastal estate with a Nano Wall glass system and two custom staircases.
In a town with many summer homes, an ADU often becomes the guest cottage that lets family visit Chatham without crowding the main house.
See our Chatham projects
“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 Chatham
We prepare the drawings, file the applications, and schedule the inspections. Here is what a project like this usually needs:
- Building permit from the Chatham Building Department, and a certificate of occupancy at the end.
- Review by the Chatham Board of Health of septic capacity under Title 5 if the ADU adds a bedroom.
- Zoning review of setbacks, height, and lot coverage under the Chatham 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 check with Chatham’s Historical Commission if the property is historic.
- 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 Chatham: FAQ
Can I build an ADU in Chatham?
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 Chatham. Setbacks, septic capacity, and conservation rules still apply, so we check your lot first.
Do you build ADUs in Chatham Village and North Chatham?
Yes. We build detached and attached ADUs all over Chatham, including Chatham Village, North Chatham, South Chatham, West Chatham, and Chathamport. Our base in South Yarmouth is about 13 miles away.
Will my septic system handle an ADU in Chatham?
Chatham is extending town sewer neighborhood by neighborhood, and homes not yet connected are on septic. On septic, Title 5 sizes the system by bedroom count, so an ADU with a bedroom can mean a septic upgrade. The Chatham Board of Health reviews it before the building permit.
Can I rent out an ADU in Chatham?
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 the Chatham rules before you plan on summer rentals.
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