How Much Does a Home Addition Cost in Massachusetts?
- Jun 22
- 2 min read
Quick answer: In Massachusetts, a home addition typically costs $150 to $400 per square foot, with most projects totaling between $50,000 and $250,000 depending on the room type and finishes. Kitchens and in-law suites cost the most because they require plumbing and electrical work; bedrooms and family rooms cost less. A simple bump-out can start around $25,000–$45,000.
Cost by addition type (Massachusetts, 2026)
Bump-out / small addition: $25,000 – $50,000
Bedroom addition: $50,000 – $100,000
Family room addition (~300 sq ft): $45,000 – $120,000
Kitchen addition / expansion: $60,000 – $150,000
In-law suite addition: $100,000 – $200,000+
Per square foot: $150 – $400
Why the range is so wide
Room type — “wet” rooms (kitchens, bathrooms, in-law suites) cost more than bedrooms or family rooms.
Finishes — stock vs. custom cabinetry, flooring, and fixtures can swing the budget by tens of thousands.
Foundation and site work — a slab, crawlspace, or full basement under the addition changes the price.
Town — permit fees and labor rates vary across Massachusetts.
Tying into the existing home — matching the roofline, siding, and systems adds work but makes the addition look original to the house.
Frequently asked questions
What is the most affordable type of addition?
A bump-out or a bedroom/family-room addition is usually the most cost-effective, since it avoids the plumbing and electrical of a kitchen or bath.
Does a home addition add value?
Yes — added square footage, especially bedrooms and updated kitchens, is among the strongest investments for resale in the Greater Boston market.
Do I need a permit for a home addition in MA?
Yes. Every addition requires a building permit, and we handle the permitting and inspections for you.
Get a free addition estimate
Family-owned since 1984, Kneeland Construction designs and builds additions of every type across Greater Boston and the South Shore. Call 781-393-9899 or request a free estimate today.