Home Addition Cost in Boston, MA
Home Addition in Boston costs $210–$456 per sq ft in 2026. A typical 300 sq ft project averages $90,000. Boston pricing runs roughly 20% above the Northeast regional baseline.
- Per sq ft
- $210–$456
- Typical range
- $63,000–$136,800
- Average
- $90,000
- Labor share
- 50%
Boston, MA Average Cost (2026)
What Drives Home Addition Costs in Boston
Permits & zoning
Boston building permits for additions cost $1,500–$3,500 plus zoning review and design review for many neighborhoods. Historic district restrictions apply in Beacon Hill, South End, Back Bay, and parts of Charlestown — material and design constraints can add 20–40% to costs.
Climate & construction
Frost depth is 48 inches in Suffolk County. Climate zone 5 requires R-20 walls and R-49 ceilings. Older Boston homes (pre-1920) often need lead paint abatement and asbestos surveys before any addition work. Brick veneer and ornamental masonry detail are common matching requirements.
Local market
Typical Boston additions are 200–400 sq ft, often dormer-type for second-floor expansion since lot sizes are constrained. Carpenter labor exceeds $100/hour in many neighborhoods. Total project costs run 15–25% above the Northeast regional baseline.
Information reflects general guidance for Boston, MA; permit fees, code requirements, and zoning rules change — always confirm with the local building department before starting work.
Cost Breakdown
Based on a 300 sq ft project in Boston, MA. Actual costs vary by contractor, site conditions, and material choices.
Home Addition Cost by Size in Boston
Boston pricing for common home addition project sizes (2026).
| Project size | Low | Mid | High |
|---|---|---|---|
| 150 sq ft | $31,500 | $45,000 | $68,400 |
| 300 sq ft | $63,000 | $90,000 | $136,800 |
| 600 sq ft | $126,000 | $180,000 | $273,600 |
Based on $210–$456 per sq ft in Boston, MA.
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Return on Investment
How much value does a home addition add to your home at resale?
How Home Addition compares to other projects
ROI figures based on Remodeling Magazine Cost vs. Value Report 2024, national averages. Actual resale value depends on your market, home price tier, and project quality.
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Frequently Asked Questions
How much does a home addition cost in Boston, MA?
In Boston, MA, a typical 300 sq ft home addition project costs between $63,000 and $136,800, averaging $90,000. Boston pricing runs roughly 20% above the Northeast regional baseline.
Do I need a permit for a home addition in Boston?
Boston building permits for additions cost $1,500–$3,500 plus zoning review and design review for many neighborhoods. Historic district restrictions apply in Beacon Hill, South End, Back Bay, and parts of Charlestown — material and design constraints can add 20–40% to costs.
What home addition size is typical in Boston?
Typical Boston additions are 200–400 sq ft, often dormer-type for second-floor expansion since lot sizes are constrained. Carpenter labor exceeds $100/hour in many neighborhoods. Total project costs run 15–25% above the Northeast regional baseline.
Does a home addition add value to homes in Boston?
Nationally, a home addition recoups about 32% of its cost at resale. For a $90,000 project in Boston, MA, that's approximately $28,800 in added home value. Resale recovery varies by neighborhood and current market conditions.
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Get Your Estimate
How big is your Home Addition?
A bedroom addition is typically 150–300 sq ft.
Pro Tips
- Get at least 3 local contractor quotes
- Confirm permit requirements with the city
- Budget 10–20% contingency
- Check contractor license and insurance
Ready to Hire a Home Addition Contractor?
Use your estimate to get competitive bids from licensed local contractors. Getting multiple quotes is the best way to avoid overpaying.
Local contractor matching coming soon.