Independent and unbiased 2026 pricing data
HouseProjectCalc

Additions

How Much Does a Home Addition Cost?

Cost by addition type

Additions vary widely by type and complexity:

  • Bump-out (a few extra feet): $20,000 to $50,000
  • Single room addition: $40,000 to $100,000
  • Second-story addition: $100,000 to $300,000+
  • Sunroom: $25,000 to $80,000

Why additions cost more per square foot

An addition costs more per square foot than a remodel because you build everything new: foundation, framing, roof, siding, windows, plus interior systems and finishes. Kitchens and bathrooms in an addition push the top of the range because of plumbing.

Estimate it yourself

Frequently asked questions

Is it cheaper to add on or build up?

Building out (on a new foundation) is often cheaper per square foot than building up (a second story), because a second story usually requires reinforcing the existing structure and temporary relocation during construction. Lot size and local rules can change this.

Does a home addition add value?

Additions add living space and usually recoup a meaningful share of their cost, especially adding a bedroom or bathroom. They rarely return 100 percent, so build for how you will use the home, not just resale.

Keep reading