Fairfax County · VA

Home Additions in Fairfax

An addition is the one project where zoning can stop you before design starts. We are a licensed contractor in Virginia (Class A #2705183185) — we pull the permits through Fairfax County Land Development Services, coordinate the licensed trades, and hand you a written line-item scope before demolition starts.

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Permits & inspections in Fairfax 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 Fairfax permit goes through Fairfax County Land Development 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 Fairfax

This one catches people out: the City of Fairfax is an independent city with its own permit office, but a great many “Fairfax” mailing addresses are actually in Fairfax County and go through Land Development Services instead. Which one you are in decides where the permit goes and who inspects the work, so we confirm it before anything is filed.

What we find in Fairfax homes

The house decides half the scope.

The area runs from 1950s–1970s ramblers and colonials near the city core to newer subdivisions further out. On the original houses, additions and kitchen expansions are the common projects, and lot coverage is usually the first constraint worth checking.

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 — Fairfax 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.

22030220312203222033ViennaOaktonChantillyCentreville

Free Fairfax walkthrough

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

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Also in Fairfax

One contractor for the rest of the house

Our Fairfax crews cover Vienna, Oakton, Chantilly, Centreville and every ZIP in the area — 22030, 22031, 22032, 22033.

Fairfax home additions questions

Straight answers

Do you handle home additions in Fairfax, VA?

Yes. United Developers is a licensed contractor in Virginia (Class A #2705183185) and works throughout Fairfax and Fairfax County, including 22030, 22031, 22032, 22033 and nearby Vienna, Oakton, Chantilly.

Who pulls the permit for a Fairfax home additions project?

We do, under our license, through Fairfax County Land Development 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 Fairfax I should know?

This one catches people out: the City of Fairfax is an independent city with its own permit office, but a great many “Fairfax” mailing addresses are actually in Fairfax County and go through Land Development Services instead. Which one you are in decides where the permit goes and who inspects the work, so we confirm it before anything is filed.

What does home additions cost in Fairfax?

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

Is the Fairfax 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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