Home Addition costs
Compare the project, repair and planning references below before choosing the work for your property. Confirm measurements, existing conditions and the services included in each proposal.
Cost scope: Benchmarks were reviewed October 24, 2026. Figures apply to the scope and market named by each reference. City/state examples outside Portland Metro are not Portland quotes. Labor, equipment, recurring expenses and complete projects are different budgets.
Installation and project costs
Compare alternatives separately. A range includes installation only when its scope says so. Do not add overlapping totals together.
| Project or reference | Published benchmark | Basis and scope |
|---|---|---|
| Home addition cost | $125 – $250 | per sq ft; home addition |
| Home addition cost | $50,000 – $100,000 | 20-by-20-foot addition |
| Cost to add a second story — Second story | $200 – $500 | per sq ft, materials and labor |
| Cost to add a second story — Full second floor | $200,000 – $750,000+ | whole-floor scenario |
| Cost to add a second story — Partial second story | $100,000 – $250,000 | partial-floor scenario |
| Is it cheaper to build up or out? | $100 – $200 | per square foot (building up) |
| Is it cheaper to build up or out? | $110 – $250 | per square foot (building out) |
| Is it cheaper to build up or out? | $50,000 – $125,000 | total cost (500 sq ft addition) |
Related RemodelRates cost guides
Explore the related RemodelRates guides for project benchmarks and planning details.
Before requesting bids
Share measurements, photos, location, existing conditions and the desired result. Ask for a written scope covering preparation, permits, removal, material specifications, installation, disposal and finish repairs where relevant. Compare bids using the same quantities and exclusions.
Material cost
No separate material-only purchase range was verified for this collection. Ask for an itemized allowance with quantities, product specifications and delivery; do not infer it by subtracting unrelated ranges.