Modular ADU vs. One-Crew Builder: Where the Surprise Costs Hide

Two ways to build an ADU in Maine & New Hampshire

There are two kinds of ADU companies working in Maine and New Hampshire right now. The first designs (or factory-builds) the unit itself, then either subcontracts the sitework or leaves it out of the contract entirely. The second — the rarer kind — is a site contractor that also builds the unit, with one crew handling everything from the first test pit to the final coat of paint.

We're the second kind, and this article is about why that difference matters more than the sticker price.

Read the fine print on any "fixed price" modular quote

Modular and factory-built ADU companies genuinely can lock the price of the *box*. What they can't lock is the ground it sits on. Look at any modular ADU contract in New England and you'll find some version of the same exclusions list:

• Septic system expansion — adding a bedroom usually means your existing system needs more capacity. That's a separate contractor and a separate (large) bill.
• Building downhill from an existing septic — now you need a pump station. Another change order.
• Well upgrades — flow or capacity issues surface after the contract is signed.
• Heavy tree clearing, stumps, and ledge — priced "upon site evaluation," which means priced after you're committed.
• The crane and the access road to get the box in — tight lots and soft ground are your problem, not the factory's.

None of this makes modular companies dishonest. It makes them box-builders. The 15–30% of the project that lives in the dirt is exactly the part they don't control — so they exclude it, estimate it loosely, or hand it to a sub you've never met.

What "one crew, dirt to done" actually means

Langone Site Services is an excavation company that builds ADUs — not the other way around. That changes what a quote means:

• We own the excavators, graders, and dump trucks. Site prep isn't a subcontract line item with someone else's margin stacked on it. It's Tuesday.
• We're Maine DEP-certified and install septic systems ourselves — soil test through tank install. The single most common "surprise cost" in ADU building is a core service we price up front.
• Clearing, stumps, drainage, and ledge are our day job. We walk your lot before we quote, so the quote already reflects your actual site — not a hypothetical flat one.
• One contract. When the same company digs the hole and hangs the cabinets, there's no gap between contractors for costs to hide in.

That's why our published model prices — from $135,000 for The Bean to $294,300 for Ella's Retreat — are all-in numbers, and why our promise is simple: your quote is your price.

Speed: 8 weeks vs. "it depends"

Coordination is the hidden tax on multi-contractor builds. The factory is done but the septic sub is booked three weeks out; the foundation crew is waiting on the clearing crew; every handoff is a place to lose a week. Running one crew is how we finish most builds in about 8 weeks once permits are in hand — while multi-contractor projects in the region routinely stretch across two seasons.

Questions to ask any ADU builder before you sign

1. Is septic — including expansion of my existing system — in this price or excluded? 2. Who does the excavation and site prep, and do you employ them or sub it out? 3. What happens to the price if you hit ledge, need a pump station, or the perc test comes back tight? 4. Is tree clearing and stump removal included, or "evaluated on site"? 5. Can I see a finished unit in person? (Our display models are going up right now — reserve a walkthrough.)

If the answers involve the words "allowance," "excluded," or "TBD," you don't have a fixed price. You have a starting bid.

The bottom line

A modular box with an open-ended sitework bill isn't cheaper — it just moves the risk onto you. Before you commit, get an instant, all-in price from the crew that owns the dirt.