Basement Finishing Nassau County

Nassau County's Basement Contractor — Since 2011

Basement Finishing Nassau County

LI Basement Pro serves all of Nassau County — from Hicksville and Levittown to Garden City and Valley Stream. Licensed Nassau County contractor with 300+ Nassau basements completed.

4.9 — 187 Reviews
🏠580+ Basements Completed
Licensed & Insured
🏆BSI Certified

Mon–Sat, 7am–5pm · Free Estimate · No Obligation

Free Estimate — No Obligation

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Responds within a few hours · Mon–Sat 7am–5pm

Or call directly: (631) 625-8649 · Free Estimate · No Obligation

4.9 Stars — 187 Google Reviews·🏠580+ Basements Completed·📅15 Years on Long Island·Licensed & Insured·🏆BSI Certified Dealer·🌿EPA Lead-Safe Certified·🔨NARI Member·👥14-Person Crew·🔒Nassau & Suffolk Licensed·4.9 Stars — 187 Google Reviews·🏠580+ Basements Completed·📅15 Years on Long Island·Licensed & Insured·🏆BSI Certified Dealer·🌿EPA Lead-Safe Certified·🔨NARI Member·👥14-Person Crew·🔒Nassau & Suffolk Licensed·

Nassau County Basement Experts

Basement Finishing & Waterproofing Across Nassau County

Nassau County Long Island aerial view residential neighborhoods

Nassau County is LI Basement Pro's home territory. Dan Farrelly grew up in Hicksville, and the company has been servicing Nassau County basements since 2011. We know Nassau's building department processes — from the county permit office to the individual village departments in Garden City, Hempstead, and Valley Stream.

Nassau County's housing stock is diverse but has consistent patterns. Levitt-era homes in Levittown and Hicksville are the most common basement project type — typically 550–750 sq ft unfinished basements in ranch and cape-style homes. These homes were built from the late 1940s through the 1960s and many have aging cinderblock walls that need waterproofing assessment before finishing begins.

We also do a lot of work in the higher-end Nassau communities — Garden City colonials, Manhasset estates, and Great Neck homes — where the finishing scope is typically more comprehensive: full bathrooms, wet bars, home theaters, and luxury flooring.

Nassau County Permit Information

Permit authorityNassau County Building Dept. (or village)
Typical permit cost$500–$1,500 depending on project
Average approval time3–8 weeks
Required licensesNassau County HIC License

Towns We Serve in Nassau County

Nassau County Office

218 Robbins Lane, Syosset, NY 11791

📞 (631) 625-8649Request Free Estimate

Verified Local Work

Recent Jobs in Nassau County

Real jobs completed by our crew across Nassau and Suffolk Counties.

Basement Finishing in Hicksville, NY
🏠 Basement Finishing
Hicksville, NYMar 2026

650 sq ft basement with LVP flooring, recessed lighting, and egress window

Basement Remodeling in Hicksville, NY
🔨 Basement Remodeling
Hicksville, NYNov 2025

Full remodel: new plumbing rough-in, drywall, recessed lights, LVP flooring

Basement Waterproofing in Levittown, NY
💧 Basement Waterproofing
Levittown, NYMar 2026

Interior drainage system + dual sump pump installation on cape-style home

Basement Finishing in Commack, NY
🏠 Basement Finishing
Commack, NYFeb 2026

800 sq ft basement with home office, bathroom rough-in, and drop ceiling

Egress Window Installation in Garden City, NY
🪟 Egress Window Installation
Garden City, NYFeb 2026

Two egress windows with full excavation and waterproofed window wells

Sump Pump Installation in Hauppauge, NY
Sump Pump Installation
Hauppauge, NYFeb 2026

Battery backup sump pump system after basement flooding

Basement Finishing in Mineola, NY
🏠 Basement Finishing
Mineola, NYFeb 2026

550 sq ft playroom/guest suite conversion with full drywall and LVP

Basement Waterproofing in Smithtown, NY
💧 Basement Waterproofing
Smithtown, NYJan 2026

Exterior waterproofing membrane + interior french drain system

Got Questions?

Nassau County Basement FAQs

Yes. Nassau County requires building permits for basement finishing, including electrical, plumbing, and structural work. The Nassau County Building Department processes permits — our office manager Karen handles all applications. Permit costs in Nassau typically run $500–$1,500 depending on project scope.

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Mon–Sat, 7am–5pm · Free Estimates · No Obligation · Licensed & Insured