Looking for an addition contractor in Old Westbury, NY? Describe your project once and up to three addition contractors who work in Old Westbury and Nassau County get back to you with a quote. It's free and there is no obligation.
Old Westbury is home to about 4,950 people (2024 Census Bureau estimate), a growing community (+15.2% since 2020). With 577 people per sq mi, it is a semi-rural area. Growing families here often add space instead of moving.
Old Westbury at a glance
- Population (Census Bureau estimate, 2024)
- 4,950 (+15.2% since 2020)
- Rank in New York
- 172nd of 595 cities and towns
- Land area
- 8.6 sq mi
- Population density
- 577 people per sq mi (semi-rural)
- Type
- Village (Old Westbury village)
- Main county
- Nassau County
What to check before hiring in Old Westbury
- Zoning: check Old Westbury's setbacks, lot coverage and height limits first.
- License and permit: in New York, additions are built by licensed contractors under a permit.
- Structure: second stories need an engineer to check the existing house.
- Price drivers: size, foundation, roof tie-in, plumbing and finishes.
Useful official resources
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ICC: International Code Council
Official information and guidance.
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NAHB
Official information and guidance.
Services available in Old Westbury
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Room addition
Ground-floor addition with foundation, framing, roof and finishes.
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Second-story addition
New floor over the existing house, with structural engineering.
Frequently asked questions in Old Westbury
How much does an addition cost in Old Westbury, NY?
It depends on size, foundation and finishes. Describe your project: contractors who serve Old Westbury reply with a quote.
How long does it take?
Often a few months, plus design and permits.
Does an addition raise property taxes?
Usually, since it increases the assessed value.
Which addition contractors will contact me?
Up to three independent addition contractors who serve Old Westbury and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.