ADU Construction Process in Waldorf, MD

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Ready to talk timeline? Tell us about your project — we'll lay out the phases.

Construction crew raising framed walls of a backyard cottage

The phases, in order

1. Site prep and foundation

We mark the ADU's exact footprint from the site plan, clear only what the plan allows, and pour the foundation. The county inspects at its required stages, including foundation — we schedule and meet every one.

2. Framing and roofing

Walls go up, the roof goes on, and you can finally walk through the rooms instead of imagining them. This is the phase your neighbors notice most.

3. Rough-ins: electrical, plumbing, HVAC

Licensed trades run the wires, pipes, and ducts before the walls close. Each trade permit costs $28 under the county's published fee schedule — real numbers, not guesses.

Sources: Charles County FY2027 Fees & Charges (effective 7/1/2026): trade permits $28 each.

4. Insulation and drywall

Insulation, then drywall, then the first sense of what the finished space will feel like. More inspections at the county's required stages.

5. Finishes

Fixtures, floors, cabinets, paint, trim — the selections you made during design become real rooms.

6. Final inspections

The county's final inspections confirm the work meets code. Inspection fees run $94–$328 depending on the inspection, per the county's published schedule.

Sources: Charles County FY2027 Fees & Charges (effective 7/1/2026): inspections $94–$328.

How long it takes

Two published benchmarks from real DMV builders: Excell Homes publishes 12–16 weeks of build time inside a 5–7 month start-to-move-in window (2–3 weeks design, 30–60 days permits, 12–16 weeks build); Makara ADU reports about 3–4 months of construction (quoted in The Banner). Those are their projects, their numbers — every project differs, and your feasibility study and design set your real timeline. No county publishes a typical review timeline, so anyone promising "built by" dates is guessing.

A note on prices: material costs move up and down, and no two lots need the same work. Treat any numbers on this page as starting points, not quotes. Your written estimate after our free lot walk is the real number for your project.

Living through it

A detached ADU is the easiest build to live through — the work stays in the backyard, and your house is your house. An attached ADU or conversion shares your walls, so expect noise against them during work hours. Either way: set hours, protected landscaping, daily cleanup. We don't pretend it's invisible, and we don't leave your yard looking like a staging area.

Who's on your property

A project manager runs the job day to day, and licensed trades handle electrical, plumbing, and HVAC. You know the schedule, you know who's coming, and you have one person to call — not a phone tree.

Check it yourself — or skip the homework

Zoning and permit questions: Charles County Planning & Growth Management, 301-645-0692. The county's published draft rules are Bill 2026-06 / ZTA 25-189 ("Flexibility for Accessory Dwelling Units").

Or skip the homework: call (240) 222-5082. When the build wraps, here's what the final walkthrough looks like — and where we build.

Questions homeowners ask us

How long does construction take?

Two published DMV benchmarks: Excell Homes publishes 12–16 weeks of build time inside a 5–7 month start-to-move-in window; Makara ADU reports about 3–4 months of construction (The Banner). Every project differs — your feasibility study and design set your real number, and we won't promise a date the county's review clock can't guarantee.

Will my yard be destroyed?

Construction is messy — we won't pretend otherwise. But we clear only what the site plan allows, protect landscaping outside the work zone, keep set hours, and clean up daily. A detached ADU keeps the work in the backyard; attached work shares your walls.

Who will be on my property?

A project manager runs the job, plus licensed trades for electrical, plumbing, and HVAC. You get the schedule in advance and one person to call.

How do inspections work?

Charles County inspects at its required stages — foundation, framing, rough-ins, final. We schedule every inspection, meet the inspectors, and handle any corrections. Inspection fees run $94–$328 per the county's FY2027 schedule.

Can we live at home during the build?

Almost always yes. With a detached ADU, your house is untouched. With an attached ADU or conversion, expect daytime noise — but you keep your home. If your project is unusual enough that you can't, we'll say so during design, not during week three of framing.

What happens after you reach out

No mystery, no sales script. Here is the whole path from first call to move-in day.

1You reach outCall or send the form. Tell us about your lot and what you want the space for — a parent, rental income, a home office.

2We walk your propertyFree visit. We check setbacks, access, slope, trees, and utilities, and tell you honestly what fits.

3You get a plan and a priceA site plan and a written estimate for your lot. No pressure, no obligation, no fine print.

4Permits, then buildWe handle the Charles County paperwork and follow-ups. Then our partner builders build it.

What Happens on Build Day — and Every Day After