How Much Does a Second-Story Addition Cost in Massachusetts?
- Jun 22
- 2 min read
Quick answer: In Massachusetts, a second-story addition typically costs $300 to $700+ per square foot, or roughly $120,000 to $350,000+ for a full second floor. Building up costs about 15–20% more than a ground-floor addition because the existing structure must be reinforced to carry the new load. Final price depends on size, finishes, and your home’s existing framing and foundation.
What drives the cost of building up
Partial second story (over part of the home): $75,000 – $250,000
Full second story: $120,000 – $350,000+
Second story with primary/in-law suite: $175,000 – $400,000+
Per square foot: $300 – $700+
The biggest cost factors are:
Structural reinforcement — existing walls and foundation often need strengthening to carry a second floor.
Temporary roof removal and weather protection during the build.
Whether you stay in the home (phasing the work adds cost) or move out.
Finish level — bathrooms and kitchens add “wet” trades (plumbing, electrical) that raise the price per square foot.
Massachusetts building codes, permits, and engineering, which are stricter than the national average.
Is a second story worth it vs. moving?
For many MA homeowners on a lot they love, building up nearly doubles living space without buying new land or losing yard — often costing less than buying a comparable larger home in the same town. A second story also tends to add strong resale value in established neighborhoods.
Frequently asked questions
How long does a second-story addition take?
Most projects run 4–7 months from permit to completion, depending on size and finishes.
Do I have to move out during construction?
Not always. Many homeowners stay put, but expect a period when the roof is opened up. We plan the schedule and weather protection to minimize disruption.
Can any house support a second story?
Most can with the right structural reinforcement. We assess your foundation and framing during a free in-home consultation before any work begins.
Get a free second-story estimate
Kneeland Construction has been building additions across Greater Boston and the South Shore since 1984. We serve Norwood, Franklin, Quincy, Stoughton, Foxborough, Walpole, Sharon, Canton, Dedham and surrounding towns. Call 781-393-9899 or request a free estimate.