Montgomery County · MD

Home Additions in Gaithersburg

An addition is the one project where zoning can stop you before design starts. We are a licensed contractor in Maryland (MHIC #111971) — we pull the permits through the Montgomery County Department of Permitting Services, coordinate the licensed trades, and hand you a written line-item scope before demolition starts.

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Permits & inspections in Montgomery County

The paperwork is the part most contractors gloss over.

An addition starts with zoning, not construction: setbacks, lot coverage and height limits get reviewed before a building permit is issued, and in some neighborhoods there is a stormwater or historic review on top. Then come the footing and foundation inspections, which have to pass before backfill. This is the longest-lead permit of any project we do, and it is why we start the paperwork while the design is still being drawn.

Your Gaithersburg permit goes through the Montgomery County Department of Permitting Services. We pull it under our license and we hold the inspection schedule — you do not chase inspectors and you do not sign the application.

Local to Gaithersburg

Gaithersburg runs its own permitting for properties inside the city limits — a separate submission and separate inspectors from Montgomery County DPS. A Gaithersburg mailing address does not always mean you are inside the city, and which side of that line you are on decides where the permit goes. We confirm it before filing.

What we find in Gaithersburg homes

The house decides half the scope.

Gaithersburg spans 1960s–1980s subdivisions in the older sections and heavy 1990s–2000s townhome and single-family development further out. In the earlier neighborhoods, expect original electrical service and kitchens that have never been opened up; in the newer ones, the constraint is usually the HOA architectural review rather than the house.

What's included
  • Zoning, setback and lot-coverage review before design is finalized
  • Footings placed below the regional frost line
  • Footing and foundation inspections passed before backfill
  • Roofline, siding and HVAC tied into the existing house so it does not read as an add-on
Planning range — Montgomery County
$180 – $340 / sq ft

A planning range, not a quote. Your written line-item price comes after a free on-site walkthrough. HVAC, electrical and plumbing are performed by licensed trade partners.

2087720878208792088220886GermantownMontgomery VillageWashington GroveRockville

Free Gaithersburg walkthrough

A written, line-item scope for your home additions project. No design fee, no obligation.

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Also in Gaithersburg

One contractor for the rest of the house

Our Gaithersburg crews cover Germantown, Montgomery Village, Washington Grove, Rockville and every ZIP in the area — 20877, 20878, 20879, 20882, 20886.

Gaithersburg home additions questions

Straight answers

Do you handle home additions in Gaithersburg, MD?

Yes. United Developers is a licensed contractor in Maryland (MHIC #111971) and works throughout Gaithersburg and Montgomery County, including 20877, 20878, 20879, 20882 and nearby Germantown, Montgomery Village, Washington Grove.

Who pulls the permit for a Gaithersburg home additions project?

We do, under our license, through the Montgomery County Department of Permitting Services. An addition starts with zoning, not construction: setbacks, lot coverage and height limits get reviewed before a building permit is issued, and in some neighborhoods there is a stormwater or historic review on top. Then come the footing and foundation inspections, which have to pass before backfill. This is the longest-lead permit of any project we do, and it is why we start the paperwork while the design is still being drawn.

Is there anything specific to Gaithersburg I should know?

Gaithersburg runs its own permitting for properties inside the city limits — a separate submission and separate inspectors from Montgomery County DPS. A Gaithersburg mailing address does not always mean you are inside the city, and which side of that line you are on decides where the permit goes. We confirm it before filing.

What does home additions cost in Gaithersburg?

Most Gaithersburg projects land in the $180 – $340 / sq ft range. That is a planning range for Montgomery County, not a quote — your written price comes after a free on-site walkthrough.

Is the Gaithersburg walkthrough and estimate free?

Yes. The walkthrough and the written scope are free and yours to keep whether or not you hire us. There is no design fee and no consultation invoice.

How long does an addition actually take?

The build is rarely the long part — permitting and zoning review are. Expect the approval phase to run in parallel with final design, and expect us to give you a schedule that names the permit milestone rather than hiding it. We will tell you at the walkthrough if your lot has a setback or coverage problem, because that changes the whole conversation.

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