The short answer

For an architect-designed custom home in southern Maine, most of our recent projects have landed somewhere between $350 and $550 per square foot of construction cost. A compact, efficiently planned 1,800 sq ft home might come in around the lower end; a complex build on a difficult site, with high-end finishes and systems, can exceed the top of that range without trying very hard.

Two things about that number before you close the tab. First, it's construction cost only — we'll get to the rest. Second, per-square-foot pricing is a blunt instrument. It's useful for a first gut-check and dangerous for anything more precise, because it hides the thing that actually drives cost: complexity.

What drives the number up (and down)

Square footage matters less than people think. These matter more:

The shape of the building. Every corner, bump-out, dormer, and roof valley costs money. A simple rectangular form with a straightforward roof is the single most effective cost-control decision available — and, done well, it's not a compromise. Some of the best houses on the Maine coast are, at heart, refined barns.

Kitchens, bathrooms, and windows. These are the expensive rooms and the expensive holes. A house with two bathrooms instead of three, or with generous windows placed where they count rather than everywhere, can fund significant quality elsewhere.

The site. Ledge that needs blasting, a long driveway, a steep slope, a septic system in poor soils — site work can quietly consume 10–20% of a budget before the house begins. (This is why we wrote a whole guide about evaluating land before you buy it.)

Systems and envelope. Better insulation, high-performance windows, and heat pumps cost more up front and pay you back every February. We consider a strong envelope the last place to cut — a fancy faucet can be replaced next year; a poorly insulated wall is forever.

The costs beyond construction

The construction contract is the biggest line, but not the only one. A realistic total project budget also includes:

Land — and its closing costs, survey, and soil testing

Site development — well, septic, driveway, utility connections, clearing

Design and engineering fees — architectural fees for full service typically run 8–15% of construction cost, plus structural engineering and, on some sites, civil or geotechnical work

Permits and fees — modest in most Maine towns, but not zero

Furniture, appliances, landscaping — the things that turn a finished house into a livable one

Contingency — hold 10% of the construction budget in reserve. Not "if something goes wrong," but for when something changes. Something always changes.

A workable rule of thumb: take the construction estimate, and expect the total project — excluding land — to be 20–30% more once everything above is counted.

Why we talk about money at the first meeting

Some clients arrive apologetic about their budget, as if naming a number will limit the design. In our experience it's the opposite: the budget is a design tool. Knowing the real number early lets us put the money where it changes your daily life — light, space, warmth, durability — and be ruthless about the places it doesn't.

The projects that go wrong are almost never the modest ones. They're the ones designed to an imaginary budget, value-engineered in a panic after bids come in, and built as a compromised version of a house that was never affordable. We'd rather design you an excellent $700,000 house than a diminished $900,000 one.

Three ways to keep your budget honest

Decide early, change rarely. Decisions made on paper are nearly free. The same decision made during construction costs a change order, a delay, and usually a little goodwill.

Prioritize in writing. Before design starts, we ask clients to list what they'd protect at all costs and what they'd give up first. When trade-offs arrive — and they will — the list does the arguing.

Get real pricing early. We like bringing a builder into the conversation during design, not after it, so estimates evolve with the drawings instead of ambushing them at the end.

The bottom line

A custom home is a serious investment, and pretending otherwise helps no one. But cost surprises are not an inevitable feature of building — they're a symptom of decisions made too late and budgets discussed too little. Start with honest numbers, keep them in the room through every design conversation, and the process becomes what it should be: not a gamble, but a plan.