House extensions are the most practical way to get more space without leaving the neighborhood you love. If you are in Fairfax or Arlington and your home is bursting at the seams, AZA Builders designs and builds house extensions that blend with your architecture and boost your home’s value. From kitchen bump outs to second stories and in-law suites, we handle design, permits, and construction under one roof.
Ready for a personalized estimate? Call AZA Builders today at (571) 393-2722 or request a free quote.
Why Homeowners Choose House Extensions
A well-planned house extension gives you the rooms you actually need, right where you need them. You avoid the cost and hassle of moving, keep your school district, and tailor your home to your life.
Benefits you will feel on day one
- Extra living space where it matters most: larger kitchens, family rooms, primary suites, home offices.
- Better function and flow with smarter layouts, wider openings, and modern storage.
- Real equity because finished square footage and added beds or baths lift resale value in Northern Virginia.
- Cost certainty compared to moving once you factor agent fees, closing costs, temporary housing, and new furniture.
- Energy upgrades baked in: modern insulation, windows, doors, and HVAC zoning that lower monthly bills.
Quick local note on house extension cost: pricing in Fairfax, Arlington, and Loudoun often trends higher than national averages due to permitting requirements, labor demand, and exterior material matching. We design with cost in mind from day one so your budget stays intact.
Types of House Extensions AZA Builders Builds
Every lot, structure, and family is different. We design house extensions to your site, style, and budget, then build with clean tie-ins so it looks original to your home.
Single-Storey Rear or Side Extensions
Great for kitchen bump outs and family room expansions. Add 120 to 400 square feet for a bigger island, pantry wall, and a bright seating area. Popular in Fairfax ranches and split levels.
Double-Storey and Second-Storey Extensions
Double your space without losing your yard. Add bedrooms, a primary suite, and a loft or laundry upstairs. A strong choice in Arlington and Alexandria where lots are tight and zoning supports height if setbacks are met.
Wrap-Around and L-Shaped Extensions
Perfect for corner lots and homes with side yards. Wrap the rear and side for a connected kitchen, dining, and living zone. We align rooflines and match brick or siding. Common in McLean and Great Falls.
Conservatory and Sunroom Extensions
Bring the outside in with high-efficiency glazing, skylights, and climate control. We design for year-round comfort, not just three seasons. Loved in Leesburg and Reston for backyard views.
Garage Extensions and Garage Conversions
Add space above or convert the garage into a real living area. Ideal for ADUs and in-law suites where permitted. We add insulation, subfloor, HVAC, plumbing, and natural light. Frequent in Woodbridge and Burke.
Basement Extension or Excavation
Increase footprint downward if your lot or HOA limits expansion. We handle excavation, underpinning, waterproofing, and egress windows. Strong option in parts of Falls Church and Oakton.
House Extension Cost: Realistic Local Pricing Guide
Pricing depends on size, structure, utilities, finishes, and site access. Here are transparent ranges we see across Northern Virginia.
| Scope | Typical Size | Local Cost Range | What You Get |
|---|---|---|---|
| Small single-room bump out | 120–200 sq ft | $25,000–$60,000 | Framing, windows, insulation, flooring, electrical, basic finishes |
| Typical single-storey extension | 200–400 sq ft | $60,000–$150,000 | Kitchen or family room expansion, upgraded windows/doors, roofing, siding |
| Double-storey or second-storey | 400–1,000+ sq ft | $150,000–$400,000+ | Bedrooms, baths, stair integration, structural upgrades, exterior matching |
What drives cost
- Structure: foundation work, steel beams, roof and wall tie-ins
- Utilities: plumbing runs, electrical panel capacity, HVAC zoning or new systems
- Exterior matching: brick blend, siding profile, window spec, roofing
- Finishes: cabinetry, tile, lighting packages, fixtures, millwork
- Permits and site: zoning constraints, stormwater, soil, tree protection, access
Quick answers people ask
- How much does a house extension cost. It ranges from $25k for a small bump out to $400k+ for a major second-storey in our region.
- How much is a house extension per square foot. Expect $250–$500+ depending on structure and finishes.
- Can I get a ballpark for my ZIP. Yes. Request a tailored estimate and we will price a few options so you can compare.
House Extension Process: Step by Step
We keep your project predictable with one accountable team from design to final inspection.
- Initial Consult and Site Walk
Talk through goals, budget, constraints, and timing. We measure, photograph, and verify utilities and access. - Design and Feasibility
Concepts and 3D layouts show massing and flow. We flag structural needs early to avoid later surprises. - Planning and Permits
We prepare plans and handle submissions for Fairfax, Loudoun, Prince William, and Arlington jurisdictions, plus HOA packages when required. - Structural Engineering
Beam sizes, bearing points, foundation details, and framing specs to meet or exceed code. - Selections and Final Pricing
Windows, doors, finishes, fixtures. Itemized scope with allowances clearly labeled. - Construction
Demolition, foundation or footings, framing, exterior envelope, MEP rough-ins, insulation, drywall, trim, paint, flooring, cabinets, tile, and fixtures. - Inspections and Handover
We schedule inspections, complete punch list, and hand off warranty and maintenance info.
Typical timelines
- Small single room bump out: 8–14 weeks after permits
- Single-storey extension: 12–18 weeks
- Second-storey addition: 16–28 weeks
We can phase work so you can stay home. Temporary kitchens and dust control keep life livable.
Design and Planning: House Extension Ideas That Work
You want space that looks like it has always belonged. We design for beauty, function, and resale.
Ideas we love in Northern Virginia
- Open plan social zones that link kitchen, dining, and living without feeling cavernous
- Large sliders or bi-fold doors to patios and decks for indoor-outdoor living
- Flexible rooms that switch from office to guest suite with a pocket door and built-ins
- Natural light strategy with skylights, transoms, and window alignment that respects neighboring homes
- Energy-efficient envelope upgrades for comfort and lower bills
- Continuous flooring through old and new spaces to visually enlarge your home
Browse our gallery for style boards, finishes, and before-after inspiration. Then tell us what you like so we can design around it.
Common Challenges and How AZA Builders Solves Them
Setbacks and lot coverage
We analyze your plat and zoning early, model options, and design to comply. If a variance is possible, we handle the process and the paperwork.
Neighbor coordination
We provide drawings for friendly conversations, establish working hours, and protect property lines and landscaping.
Drainage and grading
We manage roof drainage, downspouts, and site grading so water flows away from the foundation, not into it.
Matching the façade
We source brick blends, siding profiles, and shingles that match or complement. We also use proportion and trim details to make it feel original.
Unexpected structure
We build contingency into schedules and budgets, communicate quickly, and bring engineered fixes fast so momentum never stalls.
Local Case Studies
Fairfax Kitchen Extension
- Challenge: 90s kitchen felt tight with no room for an island.
- Solution: 12-foot rear bump out, new LVL beam to open the load-bearing wall, pantry wall, and a 10-foot slider to the deck.
- Timeline: 13 weeks post-permit.
- Client quote: “It feels like a new house. We actually cook together now.”
Leesburg Second-Storey Addition
- Challenge: Outgrown one-level home on a great lot.
- Solution: Added a full second story with three bedrooms, two baths, and a vaulted stair with natural light.
- Timeline: 22 weeks.
- Client quote: “We got the space we needed without giving up our yard or location.”
Woodbridge Garage-to-ADU Conversion
- Challenge: Multi-generational living with privacy needs.
- Solution: Insulated slab, new subfloor, full bath, kitchenette, and its own HVAC zone. Exterior materials match the main house.
- Timeline: 11 weeks.
- Client quote: “Perfect for family now and flexible for the future.”
FAQs About House Extensions
How much does a house extension cost in Northern Virginia
Small bump outs start around $25k, typical single-storey projects run $60k–$150k, and second-storey additions are $150k–$400k+ depending on size and finishes.
Do I need permits for a house extension in Fairfax or Loudoun
Yes. We prepare plans, submit for permits, coordinate reviews, and schedule inspections for you.
How long does a house extension take
Design and permits can take 4–12 weeks depending on jurisdiction. Construction usually ranges 8–28 weeks based on scope.
Will my extension match the existing exterior
That is the goal. We align rooflines, match materials, and keep window proportions consistent for a seamless look.
Can I live at home during construction
Often yes. We phase work, manage dust, and set clear access. For major second-storey framing, a short off-site stay can be helpful.
Do you manage structural engineering
Yes. We handle engineering, load paths, and specifications as part of our design-build service.
What warranties do you provide
Written workmanship warranty plus manufacturer warranties on products. We review coverage at handover.
Can you help with financing or staged scopes
We can recommend financing partners and phase projects in smart stages to fit your budget.
Service Areas
We build house extensions across Northern Virginia, including Gainesville, Haymarket, Fairfax, Arlington, Falls Church, Leesburg, McLean, Fredericksburg, Oakton, Great Falls, Burke, Reston, Centerville, Fairfax Station, and Woodbridge. Ask about city-specific landing pages and local project examples near you.
Why AZA Builders For House Extensions
- Veteran-owned, licensed, insured, and local
- Design, selections, permits, engineering, and build handled by one accountable team
- Transparent pricing and weekly updates during construction
- Clean tie-ins to existing structure and finishes for a truly seamless look
- Energy-smart details and comfortable, quiet spaces
- Written warranty and support after completion
See our latest projects and reviews on our Google Business Profile.
Call To Action: Get Your Free House Extension Consultation
Ready to grow your home without leaving your street. AZA Builders makes house extensions enjoyable, predictable, and value-driven. See us on Instagram & YouTube.
Call us today at (571) 20393-2722
Fill out our Contact Form for a free estimate
Visit our Google Business Profile to see client reviews in Fairfax, Arlington, Leesburg, McLean, and beyond.
