Estimating additions and ADUs in Boston, MA
Prices for additions and ADUs in Boston, MA, how they compare with the national median and what to know when bidding here, for remodeling contractors.
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Room addition prices in Boston
Q4 2026 pricing. Ranges are rounded to the nearest $50, or $100 from $5,000 up.
1 story over a basement
$54,300 to $357,400
150 to 1,000 square feet
National median: $45,700 to $302,100.
2 story over a basement
$81,800 to $544,500
150 to 1,000 square feet
National median: $69,300 to $464,400.
How Boston compares
Across the work in the cost data, Boston prices run 17% above the national median.
More work in Boston
- Kitchen remodelsCabinets, countertops, appliances and finishes.
- Bathroom remodelsTile, fixtures, vanities and plumbing rough-ins.
- GaragesOne and two car garages, framed and sided.
- Decks and porchesFraming, decking, railings and stairs.
- PaintingInterior and exterior, by surface area and substrate.
- Electrical workService upgrades, rough-ins, fixtures and finish work.
- All of Boston, MAEvery category, against the national median.
- Additions and ADUs nationallyNational ranges, cost drivers and the estimate's structure.
Estimate additions and ADUs with Boston prices
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