Home Additions remodeling cost guide
Additions are new construction tied into an existing home, so they carry foundation, framing, roofing, and full system costs. Permits and structural tie-ins make them the priciest projects per square foot after gut jobs.
What drives home additions remodeling cost
- Foundation type and how the addition ties into the existing structure.
- Whether the addition includes a kitchen or bathroom (plumbing-heavy).
- Roofline complexity and matching existing finishes.
- Permit, engineering, and inspection requirements.
Home Additions cost calculators
Run your own numbers — each calculator gives low, average, and high estimates with material, labor, and permit breakdowns.
Estimate room addition, second story, master suite, and bump-out addition costs with permit and labor indexing.
Estimate bedroom addition costs including foundation, framing, electrical, HVAC, insulation, drywall, windows, and finishes.
Estimate master suite addition costs including bedroom, bathroom, closets, plumbing, electrical, HVAC, and permits.
Estimate accessory dwelling unit costs for detached ADUs, garage conversions, backyard cottages, and in-law units.
Planning tips
- Get an engineer involved early for load and tie-in details.
- Match rooflines and siding to protect resale value.
- Budget generously for permits — additions draw the most scrutiny.
Frequently asked questions
Across our home additions calculators, projects typically range from $43,156 to $496,195 nationally. Your exact cost depends on size, material grade, labor rates, and your local market — use the calculators below for a tailored estimate.
Foundation type and how the addition ties into the existing structure.
Yes. Labor rates, permit fees, and material costs vary widely by state and city. Our location pages adjust the national estimate for your specific market.
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