Across 26 permits filed since 2025-03-10, the median is $30,000; half of projects fall between $15,325 and $78,750. Figures are permit valuations reported to building departments. National cost guides answer this question with averages from other markets; these numbers are what homeowners in Garden City, NY actually reported when they pulled permits.
Recent filings
- Residential Air Conditioning - Install new HVAC for basement renovationVillage of Garden City · 2026-08-14$17,800
- Construction of a 7 sq. ft. first floor addition and 57 sq. ft. garage extension at the front, and a 314 sq. ft. one story open porch and 42 sq. ft. outdoor kitchen at the rear and finished basementVillage of Garden City · 2026-08-13$150,000
- Construct 60 SF front porch addition Interior alterations 1st floor, convert attic to habitable space, finished basement.Village of Garden City · 2026-07-22$115,000
How to read these numbers
Permit valuations are the project cost the applicant reports to the building department. They skew slightly low — nobody rounds up for the permit fee — and scope varies, so the middle-half range is the honest picture: half of all basement finishing permits in Garden City, NY came in between $15,325 and $78,750. We exclude permits under $1,000, jobs filed as whole-house construction, and counties whose building departments don't reliably report valuations.
Same project, other places
Basement finishing in New YorkBasement finishing in ConnecticutBasement finishing on Long Island