Across 117 permits filed since 2025-05-02, the median is $25,000; half of projects fall between $10,000 and $120,000. 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 Norwalk, CT actually reported when they pulled permits.
Recent filings
- SUPERSTRUCTURE FOR 2 STORY ADDITION ATTACHED GARAGE, MUDROOM, 2ND FLOOR PLAYROOM, FULL BATHROOM, STORAGE.City of Norwalk · 2026-10-30$342,000
- INSTALLATION 2ND FL MASTER BATH ADDITION, SHOWER CEILING RAINHEAD, TWO SINKS, 1 TOILET.City of Norwalk · 2026-10-29$9,000
- REAR 3 STORY ADDITION & RENOVATIONS TO CONVERT 1 FAMILY TO 3 FR & REAR STAIRS TO GRADECity of Norwalk · 2026-10-23$480,000
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 home addition permits in Norwalk, CT came in between $10,000 and $120,000. 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
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