Cost to Build a Custom Home on Long Island (2026)
By Lior Golan, Founder, Prestige Custom Building & Construction. Last updated September 2026.
The first thing almost every family asks me about is the cost to build a custom home on Long Island. The short answer: our new homes start from $1.5M, typically $400-500 per square foot, all-in. It’s the same range we print on our custom homes page, and I’d rather you have it now than guess.
The more useful question is what moves your number. After 30+ years building on Long Island, I can tell you it’s rarely one big thing. It’s the lot, the conditions under it, the finishes you choose, and how complete the design is before anyone prices it. Below I take each in turn, along with what the national cost figures do and don’t measure.
Key Takeaways
Our new homes start from $1.5M, typically $400-500 per square foot, all-in. The lot, the site and your selections decide where a project lands.
National figures don’t transfer. In 2025 the median contract price for a house built on the owner’s own land was $404,000 (U.S. Census Bureau, 2025), a price that leaves the land out (U.S. Census Bureau, 2025).
Interior finishes are the largest stage of construction cost nationally, at 24.1% (NAHB, 2024). Settle them before construction.
Waterfront and unsewered lots add permit and design steps, so know your lot before design begins.
How Much Does It Cost to Build a Custom Home on Long Island?
Our new homes start from $1.5M, typically $400-500 per square foot, all-in. National averages sit far below that. NAHB’s 2024 cost survey put average construction cost at about $162 per square foot, for a home averaging 2,647 square feet (NAHB, 2024). That describes a typical home in NAHB’s national builder survey, not a custom home on a Gold Coast lot.
NAHB says as much itself: its results are national averages, and the survey is “not a perfect tool for estimating costs for a particular house in a particular location” (NAHB, 2024). So why is the North Shore so different? In my experience it’s what you ask of the house and the site: more structure, more complex roofs and spans, higher-grade systems and finishes, and lots that need real work before the foundation goes in. All of it can be planned.
National Cost Figures at a Glance
Each national figure measures something different. Some include the lot, some leave it out, and none of them describes a custom home on a North Shore lot. The table sets out what each one covers, from the U.S. Census Bureau’s 2025 new-housing highlights and survey definitions, and NAHB’s 2024 construction cost survey.
National figure | What it includes | What it leaves out | Source |
|---|---|---|---|
Median contract price, homes started in 2025: $404,000 | A house built on the owner’s own land, at the price on the original contract | The land, grounds work under a separate contract, and generally later change orders | U.S. Census Bureau |
Median sales price, new homes sold in 2025: $417,400 | The house and its improved lot, sold together | Generally later change orders, and extras paid in cash outside the original price | U.S. Census Bureau |
Average construction cost, 2024: about $162 per square foot on a 2,647 square foot average | Labor, subcontractors and materials, from site work and permit fees to the final steps | The lot and the rest of the sales price, such as financing, overhead and sales commission | NAHB |
Finished lot, 2024: 13.7% of the average sales price | The lot, including its financing cost | Construction and the rest of the sales price | NAHB |
Interior finishes, 2024: 24.1% of construction cost | Insulation, drywall, trim, paint, lighting, cabinets and countertops, flooring, appliances and plumbing fixtures | Every other construction stage, and the lot | NAHB |
Two rows matter most here. The Census contract price, the closest match to building on land you own, leaves out the land and, generally, changes made after signing. And interior finishes are the biggest slice of construction and, in my experience, where a luxury home departs furthest from the average.
Does a Vacant Lot or a Teardown Change the Budget?
Yes, and before design starts. Nationally, the finished lot averaged 13.7% of a new home’s sales price in NAHB’s 2024 survey (NAHB, 2024). On the North Shore, where land is expensive, treat the lot as its own budget line from day one.
A vacant lot can look simpler. It may still need clearing, grading, a driveway and utility connections, and on an unsewered lot a septic system designed from scratch.
A teardown has its own list. New York’s Industrial Code Rule 56 requires an asbestos survey before demolition work (New York State Department of Labor, 2026), and a house slated for demolition doesn’t qualify for the homeowner exemption, so any asbestos found must be removed by licensed asbestos contractors. Add utility disconnections and the old foundation, and ask each builder, me included, how those items are handled in their number.
Still deciding whether to take the house down? I cover that in knockdown-rebuild on the Gold Coast. Still shopping for land? Start with how to choose the right lot for a custom home. If the house is worth keeping, our renovations start from $500K, typically $380-430 per square foot, all-in, as our renovations page sets out. More on what drives a renovation budget is in the cost to gut and renovate a house on Long Island.
How Do North Shore Site Conditions Affect Cost?
Site conditions decide how much work happens before the house itself. Near the water, New York’s Department of Environmental Conservation regulates tidal wetland adjacent areas that extend up to 300 feet inland from the wetland boundary, and it requires a permit for almost any activity that alters them (NYSDEC, 2026).
DEC’s list of regulated construction includes residences and septic systems (NYSDEC, 2026), and the U.S. Army Corps of Engineers may require its own permit either way. On a harbor-front lot in Sands Point or Lloyd Harbor, that shapes where the house and septic sit.
Sewer or septic comes next. In Suffolk County, 74% of residents rely on cesspools and septic systems (Suffolk County, 2024), and the county’s Sanitary Code has required an innovative and alternative (I/A) onsite wastewater system for new-construction applications submitted since July 1, 2021 (Suffolk County Department of Health Services, 2025). If your lot isn’t on a sewer, plan that system from the start.
Soil and grading are quieter drivers. A sloped lot, old fill or poor drainage changes what the foundation needs, which is why my process starts with the lot, before design.
Want this in one place to plan from? Our free Custom Home Building Guide walks through the six things that move the cost of a custom home and the questions worth answering before you ask any builder for a price.
Why Do Selections and Finishes Swing the Budget So Much?
Because finishes are the biggest single stage of construction. NAHB’s 2024 survey put interior finishes at 24.1% of average construction cost nationally, ahead of major system rough-ins at 19.2% and framing at 16.6% (NAHB, 2024). On a luxury home, the range of choices inside each finish category is far wider.
Stone or tile, custom millwork or stock cabinetry, the windows, the lighting, the fixtures: two houses the same size can land far apart on these choices alone. None of that is wrong. It just needs deciding before construction, so the price describes the house you’ll actually live in.
On our projects, you choose materials inside a photorealistic 3D model of your home, with real products, and our interior architecture process specifies them, coordinated with the design by our licensed architect partners.
Design and Permits: What Happens Before Pricing
How complete the design is decides how accurate your price can be. On our design-build projects the architecture is performed by our licensed architect partners (or by an architect you bring) and resolved on paper before construction is priced, as our process lays out.
Permits are part of the plan: a current survey, plans filed for review, and on some lots an environmental permit or a variance, each with its own consultants and fees. Approval timing depends on the lot, so I won’t guess at it here. I cover the steps in the Long Island custom-home permit and approvals process, and the phases of a build in how long it takes to build a custom home on Long Island.
How Do You Compare Two Builders’ Numbers?
Compare what each number covers before you compare the numbers. The Census Bureau defines a contract price as the price on the original contract, generally before change orders (U.S. Census Bureau, 2025), so any number is only as good as the drawings and selections behind it.
Ask each builder what’s included and what’s left as an allowance, who performs the architecture, how finishes are priced, and how changes are handled. Why does this matter so much? Two numbers can look close and describe very different houses. The full list is in what to ask a custom home builder before you sign, and how to weigh the answers is in how to choose a custom home builder on Long Island.
For my part, your budget is set before construction begins, from the home you walked through in 3D, as our custom homes page shows step by step. To see finished work, start with the Brookville Cedar Estate in our portfolio.
Frequently Asked Questions
Why don’t national figures for custom home cost per square foot apply on Long Island?
Because they’re national averages. NAHB says its survey sample isn’t large enough for a geographic breakdown, that building practices and the cost of labor, land and, to some extent, materials vary from place to place, and that the survey describes a typical home built by a subset of NAHB builders (NAHB, 2024).
Is the land included in the cost to build a custom home?
Not in the standard national figures. The Census Bureau’s contract price for a house built on the owner’s land leaves the land out (U.S. Census Bureau, 2025), and its 2025 median was $404,000 (U.S. Census Bureau, 2025). If you’re buying land, plan it as its own line, and ask any builder exactly what their number covers.
How does a luxury custom home compare with the median new home?
The national median describes a very different house. The median new single-family home sold in 2025 went for $417,400 (U.S. Census Bureau, 2025), and that price includes the lot (U.S. Census Bureau, 2025). A luxury custom home asks for more structure, more complex systems and a different level of finish, so your lot, site and selections decide where yours lands.
Does a teardown cost more than building on a vacant lot?
It depends on the house and the lot. A teardown adds steps a vacant lot doesn’t have. New York requires an asbestos survey before demolition work (New York State Department of Labor, 2026), and the old utilities and foundation have to be dealt with. Ask each builder how those items are handled in their number.
Do I need a septic system for a new home in Suffolk County?
Only if your lot isn’t served by a public sewer. In Suffolk County, 74% of residents rely on cesspools and septic systems (Suffolk County, 2024), and the county has required an I/A system for new-construction applications submitted since July 1, 2021 (Suffolk County Department of Health Services, 2025). Your survey and site investigation answer this early.
Where your number lands depends on the lot, the site, the size of the house and your choices inside it, and most of that can be settled before construction.
I take on only 5-6 projects a year. After 30+ years building on Long Island and 100+ homes built and renovated, I’ve found the most useful first step is a conversation about your lot, your plans and your budget. Book a private conversation.
Lior Golan is the founder of Prestige Custom Building & Construction, a custom home builder serving Long Island’s Gold Coast and the Hamptons. Over more than 30 years he has guided over 100 custom homes and renovations across the North Shore, from Roslyn and Sands Point to Cold Spring Harbor.
Architectural and design services are provided by independently licensed architects. Prestige Custom Building & Construction, Inc. is a licensed home-improvement/construction company and is not a licensed architecture firm.
