The ADU Builder Virginia Homeowners Are Looking For
Searching for the best ADU builder in Virginia? Here's what to actually look for — and why ADU-specific experience matters more than a generic home-builder badge.
Written by Dan Caporale, Principal, Hearthstone Design BuildFact-checked August 22, 2026.
Searching for "best ADU builder Virginia" usually means one of a few things: you need space for aging parents, you want rental income from your existing lot, or you're trying to add a home office or guest suite without moving. Virginia Backyard Homes is a Virginia-based design-build firm focused specifically on accessory dwelling units — not a general home builder that takes on ADUs as a side project, but a firm built around this one building type and the zoning, permitting, and construction problems specific to it. If you're comparing ADU builders in Virginia, here's what to actually look for, and why that's the standard we hold our own work to.
Key facts
- Firm
- Hearthstone Construction, LLC d/b/a Virginia Backyard Homes — a design-build firm focused on accessory dwelling units.
- License
- VA Class A Contractor License #2705195817.
- Service area
- Homeowners across Virginia, with particular depth in Loudoun, Fauquier, Clarke and Albemarle counties.
- What we build
- Detached backyard cottages, garage and basement conversions, and attached in-law suites.
- SB 531
- Effective July 1, 2027, every Virginia locality must permit at least one ADU by-right on single-family lots, with permit fees capped at $500.
- Typical cost
- Interior conversions $60,000–$150,000; new detached cottages $180,000–$400,000+ (roughly $180–$400+ per finished square foot).
- Contact
- 571-556-1900 · 19 N King St, Leesburg, VA 20176.
Why "Best" Comes Down to ADU-Specific Experience
An ADU is not a scaled-down house. It's a distinct building type with its own set of constraints: local zoning ordinances that vary meaningfully county to county and even jurisdiction to jurisdiction across Virginia, setback and lot-coverage rules that weren't written with a second dwelling in mind, utility and septic/sewer capacity questions specific to adding a unit on an already-developed lot, and — increasingly — owner-occupancy or rental-restriction rules that differ by locality. A builder who mainly frames single-family homes and occasionally takes on an ADU is relearning these rules on your project. A builder who works exclusively in this space isn't.
What Virginia Backyard Homes Does
Virginia Backyard Homes designs and builds accessory dwelling units for Virginia homeowners as a design-build firm — meaning we handle the design, the permitting process, and the construction under one roof, with one team accountable for the project start to finish. That structure matters for ADUs specifically: because zoning and permitting questions for a second unit on an existing lot are often the hardest and slowest part of the project, having the designer and the builder be the same team means those questions get resolved early, in coordination with the build plan, instead of getting discovered mid-permit and sent back for redesign.
We work with homeowners across Virginia to evaluate whether a lot can support an ADU under local zoning before any design work begins, then carry the project through design, permitting, and construction to a finished, livable unit — whether that's a detached backyard cottage, a garage conversion, or an attached suite.
Virginia Backyard Homes is affiliated with Hearthstone Design Build, a Virginia Class A licensed design-build firm (License #2705195817) with a background in estate-scale timber-frame and commercial construction across Loudoun, Fauquier, Clarke, and Albemarle counties. That affiliation means Virginia Backyard Homes ADU projects are backed by an established design-build operation with real construction management infrastructure behind it.
Documented builds by the team behind this firm
These are completed Hearthstone Design Build projects — commercial and estate work, not ADUs, and labelled as such. Each is published with a full case study you can read and verify.
Lark Brewing Co.
Aldie, Loudoun County, VirginiaA destination brewery campus built from raw acreage — well, septic, VDOT entrance and fire suppression brought in from scratch on a 14-acre rural parcel.
Walsh Family Wine
Purcellville, Loudoun County, VirginiaA 14,400 sq ft two-building estate winery campus in the heart of Virginia's densest wine corridor, delivered design-build from schematic through commissioning.
Tuttaposto
Loudoun County, VirginiaA 4,200 sq ft hand-joined timber frame residence, designed with S.E. Wagner Architecture and delivered on a single accountable design-build contract.
How we work, from first call to finished unit.
Zoning and feasibility review.
Before any design work, we check what your specific lot and locality actually allow.
Design.
We design the unit to fit your lot's constraints and your intended use.
Permitting.
We manage the permitting process directly with your locality.
Construction.
One team carries the project from permit to finished unit.
Handoff.
You get a completed, code-compliant ADU and a direct point of contact.
Choosing an ADU builder in Virginia
How do I choose the best ADU builder in Virginia?+
Ask three things before anything else: has the firm worked in your specific locality, will it run a zoning and feasibility review before you pay for design, and does the same team carry the project through permitting and construction. ADU rules vary meaningfully county to county in Virginia, so local permitting experience matters more than a general home-building résumé.
What does a design-build firm do differently on an ADU?+
Design-build means design, permitting and construction sit with one accountable team. On an ADU, zoning and permitting for a second unit on an already-developed lot is usually the slowest part of the project, so having the designer and builder be the same team means those questions get resolved up front instead of being discovered mid-permit and sent back for redesign.
Can I build an ADU on my lot in Virginia right now?+
It depends on your locality. Some Virginia jurisdictions already allow detached ADUs by-right, others allow interior units only, and a few still require a special-use permit. Our county rules pages break down the current rule and what changes in 2027 for each jurisdiction we serve.
What changes on July 1, 2027 under SB 531?+
SB 531 requires every Virginia locality to permit at least one accessory dwelling unit by-right on single-family lots, caps permit fees at $500, requires setback parity with the primary home, and removes any family-relation requirement. It does not remove building code, septic capacity or utility constraints.
What does an ADU cost in Virginia?+
Interior conversions typically run $60,000–$150,000. New detached backyard cottages typically run $180,000–$400,000+, roughly $180–$400+ per finished square foot depending on site work, utilities and finish level. Our cost guide breaks the number down by trade.
Next steps: check the rule for your jurisdiction on our county rules pages, read what changes under SB 531 in 2027, or see the broader guide to ADU builders in Virginia. You can also review the construction work behind the firm.
Where We Work
Virginia Backyard Homes serves homeowners across Virginia, with particular depth in Loudoun, Fauquier, Clarke, and Albemarle counties through our affiliation with Hearthstone Design Build's established regional presence.