ServiCover📌 Key Takeaway: Most additions run $125-$250 per sq ft. Kitchens and bathrooms cost the most per foot because of plumbing, electrical and fixtures.
Cost per Square Foot by Addition
| Type | Per Sq Ft |
|---|---|
| Room addition | $125-$250 |
| Bump-out | $85-$200 |
| Bedroom | $125-$175 |
| Bathroom | $175-$225 |
| Primary suite | $150-$225 |
| Kitchen | $200-$250 |
| Sunroom | $100-$350 |
| Second story | $200-$500+ |
| ADU / in-law suite | $100-$300 |
| Attic conversion | $50-$150 |
| Basement conversion | $50-$100 |
Typical Totals
| Project | Typical Cost |
|---|---|
| Bedroom addition | $15,000-$25,000 |
| Bathroom addition | $7,000-$11,000 (small) |
| Primary suite | $45,000-$135,000 |
| 20x20 room | $50,000-$100,000 |
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Get Free Quotes →Frequently Asked Questions
Why are converted spaces cheaper?
Attics, basements and garages already have a foundation and roof, so you mainly pay for finishing.
Do additions raise property taxes?
Usually, because they increase assessed value.
🔎 How we research: The ServiCover Editorial Team compiles prices and guidance from published 2026 cost guides, manufacturer information and industry sources. Prices are national ranges and vary by location, home and provider, so always compare written quotes. We don't perform the work ourselves, and we may earn a commission when you request quotes through our partners — see our Advertiser Disclosure.