HomeCostGuide

Home Addition Cost in 20 US Cities (2026)

Construction of new living space added to an existing home.

National Average (per project)
Low
$20,000
Average
$45,000
High
$80,000

Home Addition Cost Breakdown

ItemDescriptionLowHighUnit
FoundationSlab, crawlspace, or basement foundation$10$30per sqft
FramingWalls, roof tie-in, headers, and sheathing$12$25per sqft
RoofingNew roof section tied into existing roof$5$15per sqft
Exterior finishSiding, windows, and exterior trim to match$8$20per sqft
ElectricalNew circuits, outlets, lighting, panel capacity$5$15per sqft
Plumbing (if applicable)Water/drain lines for bath or kitchen addition$0$25per sqft
HVAC extensionDuct runs and tonnage increase for new space$3$10per sqft
Interior finishDrywall, paint, flooring, trim, doors$10$30per sqft
Permits & engineeringBuilding permit, structural engineering, plan review$1,000$5,000flat
General contractor overheadProject management, coordination, insurance$8$20per sqft

* These are national average costs. Actual prices vary by city — select a metro below for local estimates.

Construction of new living space added to an existing home.

Home Addition Cost by City