Home Additions
Home Additions in Montgomery County, Maryland
Room additions, second stories, and primary suites for homeowners in Bethesda, Rockville, Gaithersburg, and across the DC metro, from a builder headquartered right here in Montgomery County.
Home Additions in Montgomery County & the DC Metro
More space, built to match the home you already have.
Excell Homes is headquartered in Gaithersburg, Maryland, and Montgomery County is our home market. We design and build home additions across Bethesda, Rockville, Gaithersburg, Chevy Chase, Potomac, and North Potomac, and we also serve Washington DC and Northern Virginia. Over more than 20 years and 2,500+ projects, additions and whole-home work have been a core part of what we do.
Whether you are bumping out a kitchen, adding a primary suite, building up a second story, or creating an in-law suite, we handle the design, structural engineering, permitting, and construction under one fixed-price contract, and we match the addition to your existing home inside and out.
Financing available, see your options →
We build additions across Gaithersburg, Bethesda, Rockville, Chevy Chase, Washington DC, Fairfax, and the greater DC metro. See where we work →
What we offer
- Room additions & bump-outs
- Second-story additions
- Primary suite & in-law suite additions
- Kitchen & family room expansions
- Sunrooms & four-season rooms
- Structural engineering & foundations
- Roof tie-ins & exterior matching
- Full mechanical, electrical & plumbing
- Montgomery County DPS permitting
- Design, permits & build in one contract
What it costs
Planning your budget
In the DC metro, home additions generally run about $150 to $500 per square foot, with ground-floor additions on the lower end and second-story additions higher. The final number depends on size, how much structural work is involved, and the level of finish.
For a full, jurisdiction-by-jurisdiction breakdown, see our home addition cost guide for the DC metro.
These are broad market ranges to help you plan, not quotes. Every project is different, and the only accurate number comes from a walkthrough of your space.
How it works
From first call to final walkthrough.
01 Free consultation
We visit your home, learn your goals and budget, and give you an honest read on scope and a realistic planning range.
02 Design
We design the space and prepare the drawings for permitting. You approve the plan and a fixed price before any work begins.
03 Permitting
We file and manage every approval. For Maryland projects that runs through Montgomery County's Department of Permitting Services (DPS); in DC and Northern Virginia we handle the local permitting office.
04 Build
One crew and one dedicated project manager take the job from demolition through finish work, keeping it on schedule and on budget.
05 Warranty
Every project is backed by a warranty on labor and materials, and we are here well after the final walkthrough.
Local proof
Recent Maryland addition work
Our Maryland design advantage: In Maryland we handle design in-house, so drawings, permits, and construction all stay under one roof and one contract. In Virginia and DC we work with a licensed architect partner for the design drawings, then manage the permitting and construction the same way.
Reviews
Rated 5.0 by local homeowners.
Hands down the best contractor experience I've had. They completely transformed my bathroom, the craftsmanship, attention to detail, and professionalism were exceptional throughout.
After a flood hit my home, Excell took all the pressure off, drywall, flooring, painting, plumbing, electrical. My home looks better than it did before the flood.
Excell did an amazing job remodeling my kitchen. Professional, communicative, and paid attention to every detail, the quality exceeded my expectations.
Excell Homes is very professional. I couldn't be happier with my new farmhouse sink, their work completely transformed my kitchen. Highly recommend.
Extremely satisfied with my experience. My project manager, Luis Bonilla, was superb, I credit him with the success of my two bathrooms.
A great company that does its due diligence on every job, commercial or residential. They go above and beyond, excellent service start to finish.
Excellent service from Excell Homes! They gave my bathroom the modern look it needed. I highly recommend them and will use them again.
FAQ
Questions homeowners ask us.
How long does a home addition take?
A home addition typically takes about 3 to 6 months of construction, longer for a second story or a complex primary suite. Design, engineering, and permitting happen before that, so plan for several months start to finish.
Do I need a permit for a home addition in Montgomery County?
Yes. A home addition always requires building permits, pulled through the Department of Permitting Services (DPS), covering structural, electrical, plumbing, and mechanical work. We file and manage all of it.
Is it cheaper to build out or build up?
Building out, a ground-floor addition, is usually cheaper per square foot than building up a second story, which often needs the existing structure reinforced. Your lot size and setbacks decide which is even possible, which we check during the site visit. Our addition cost guide breaks down the numbers.
Can we stay in the house during an addition?
Usually yes. Because an addition is built onto or above the existing home, we can often seal the new construction off from your living space and only connect it near the end, so you stay in the house through most of the build.
How much does a home addition cost?
In the DC metro, home additions generally run about $150 to $500 per square foot depending on whether you build out or up and the level of finish. These are planning ranges, not quotes, and our home addition cost guide breaks it down.
Do you handle the design and engineering?
Yes. In Maryland our in-house designer prepares and submits the drawings, and we bring in structural engineering as needed, so design, permits, and construction stay under one contract. In Virginia and DC we work with a licensed architect partner.
Will the addition match my existing home?
That is the goal. We match rooflines, siding, windows, and trim so the addition reads as part of the original house, not a bolt-on, inside and out.
Related: Kitchen remodeling · Bathroom remodeling · Home addition cost guide · Gaithersburg · Rockville
Ready to add on?
Tell us about your home and the space you need. We'll come back with a clear plan and upfront pricing.