Our price and cost estimate for a custom prefab home from Trillium Architects is about $350+  per square foot. This estimate is all inclusive, meaning that the cost of the plans, materials, labor, and site work are included. This cost estimate is based on their ballpark starting price for a custom home in Fairfield or Westchester County. The cost of land and any home upgrades are not included in this estimate. 

During the design process, buyers can either pay an hourly fee or agree to pay 3% of the final construction costs. The total cost to design a custom home usually adds up to about $15,000-$30,000. While a flat hourly fee may be a good choice for buyers seeking a simple design, buyers with more complex plans in mind may want to pay 3% of construction costs so they get all time they need to explain their vision. Trillium is willing to estimate construction costs per square foot free. Buyers can also hire a professional cost estimator for a more accurate itemized estimate so they have a better sense of what design cost they’re in for, although a professional estimate itself can cost $2,000 - $3,000.

Trillium is willing to manage the entire project for 15% of the construction cost. In this case they’ll create construction documents for permitting, bidding, and construction as they coordinate engineers to compile a comprehensive permit/construction package. Trillium will then help buyers find a contractor and analyze bids. They’ll even oversee construction until the completion of the home. However, it’s worth noting that Trillium only takes on projects with estimated construction costs of at least $200,000. Many small ADUs, tiny homes, or other low-cost structures may be out of the question.

It is important to note that since buyers choose a third party builder and manufacturer, completed home costs can vary greatly based on the project location, materials, manufacturer, and contractor. For example, a modular manufactured home will likely be much cheaper than working with a luxury builder, even if the final design plans are similar.