How Much Does It Cost To Build A Custom House?

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Obviously, the first step is acquiring a desirable piece of land empty or with a knock-down house. The purchase of land many times can be emotional or from the heart, but there are things to consider when determining the cost to build a house in New York, such as:

  • Open land in field or forest
  • The overall aesthetics and atmosphere of waterfront, mountain forest, or open space environment. This can also depend on the area you are looking in – Hamptons vs. Catskills.
  • Flat or sloped terrain, both have advantages.

The other factors, not so obvious:

Type of surrounding home aesthetic. Do you want to be the only modern home in a colonial village? I have seen Architectural Review Boards turn down modern-style homes because they are too dissimilar to the surrounding homes. Many people have built beautiful homes, just on the wrong site. Consider the type of neighborhood and architectural examples.

  • Sewer or cesspool
  • School district/librairies
  • Access road
  • Proximity to shopping centers
  • Proximity to town
  • Parks/golf/tennis/cultural options
  • Other amenities
  • Review neighbors if possible

And, of course, the most important and overriding factor to consider when asking how much does it cost to build a custom house is… “cost”. Don’t overspend. It comes back to hurt you later on in the house build costs. Location is important, but there might be numerous pieces of land in the general location.

Basic land purchase checklist:

  • Cost
  • Location
  • The obvious (see list)
  • The not-so-obvious (see list)
  • Emotion – how you feel on the property is very, very important!

Now you have a great piece of land, so let’s move on.

The other major components that come into play when asking how much does it cost to build a custom house:

  • Land development/landscape
  • House exterior shell
  • Interiors
  • Furnishings

Land development/landscape – Let’s start here. As we discussed – building roads, putting in cesspools, clearing trees, working the terrain on a difficult site, removal of an existing structure – all adds up.

Mojo Stumer will analyze the site/sun direction, hook-ups (if any) to sanitation, electric, and of course local code and zoning to find the best possible building envelope that will accomplish your overall goals. Mark Stumer sits on the Planning Board in Kings Point, Long Island, New York, and is an expert on residential land planning.

House Build Costs – depending on the size of land, level of design, and availability of utilities, average costs to develop and prepare land for building can run between $100,000 – $500,000 to develop an unbuilt property.

All these above factors will impact development costs. A very difficult and rural site can run away with cost. In general, we have always felt to develop the land as best as we can, design a creative final landscape plan, but remember the final landscaping can be done over a number of years. It doesn’t have to be complete on Day One if it will have an impact on your overall construction costs.

Exterior shell and interiors

In consideration of how much does it cost to build a custom house, we at Mojo Stumer believe good design in your project should not cost more money. No more than 10% of the overall budget. What do add cost to house shell is usually material and details. When budgeting to build a new house, don’t cut back on design, watch the extent of detailing and cost of materials. There are many ways to skin a cat, and there are many ways to sheath an exterior. In a discussion during your programming phase, the cost must be included as an important factor. It’s important to be realistic and get the proper guidance from your design professional. Starting off with the wrong budget or not believing real costs is a disaster waiting to happen. Below is a study of our residential projects over the last ten years.

  • $340 to $380/SF – This is achievable with minimum details and affordable materials, fixtures, and hardware. Can still create a great design in the hands of a talented designer.
  • $380 to $500/SF – More of the average range with more detail, higher-end interiors, and materials.
  • $500 to $750/SF – High-end construction costs should be able to incorporate quality materials.
    Creative design, and high-end fixtures and hardware

So, in summary of how much does it cost to build a custom house, here are the factors:

1. Site cost and difficulty to build on, quality of landscaping design

2. Shell and Interior – roughly $380 a square foot as basic average. A more detailed interior, kitchen, baths, cabinetry can easily raise that to $400-500/SF. Maximum cost should not exceed $750/SF

*COVID has had an effect on the price of materials, increasing it considerably but in the last few weeks, has come back down a little.


Mojo Stumer breaks up interiors into two areas: the basics that are included in the shell budget and the furnishings which are added later. The budget for furniture can really vary. You can buy a sofa for $3,000 or you can buy a sofa for $30,000. This phase must be managed so it does not run away with itself. Mojo Stumer believes in doing our own interior design so that the design integrates perfectly with the interiors since they are done at the same time. We start it during the Design Schematic Phase once the plans start to develop. We also have the ability to adjust and tailor the interior’s budget as we develop the architectural budget by working with both disciplines together (see the previous blog for more insight on our process). By doing both disciplines – Architecture and Interiors – we can better determine where we can spend money, go all out, temper architectural design, or cut back on architecture and let the interiors step up.

In summary, the most important element when budgeting for the cost to build a house in New York that meets your budget and exceeds your design expectations is the selection of the design professional. They will make or break your job. They can take it to a level beyond your dream. They can monitor your budget and advise you on how to keep it on track. They will become your trusted advisors. Don’t cut yourself short and be fooled by a cheap fee! Fees vary greatly but check the quality of their portfolio, look over the work they have designed, the level of design, all services offered, and their reputation among similar clients to you. You will quickly see you get what you pay for.