Accessory Dwelling Unit (ADU) Builders in Northern VA

An Accessory Dwelling Unit (ADU) is a secondary home built on the same property as your primary home. It’s known by many names: granny flat, in-law suite, backyard cottage, garage apartment, secondary dwelling unit, or casita.

With a trusted design-build firm serving Northern Virginia, you can create a custom ADU that reflects your unique needs, enhances your property’s value, and supports your long-term goals.

Schroeder Design Build ADU Full Porch Exterior

Schroeder Design Build ADU Backyard exterior

Schroeder Design Build ADU Cottage Exterior

Unlock Your Home’s Potential With An ADU Addition

An ADU addition can unlock your home’s potential by providing a secondary living space, complete with a bedroom, kitchenette, and bathroom. With an ADU addition, you can have your adult child or aging parent live close and independently. Or it can be a guest house, home office, or even a rental space for a secondary income. At Schroeder Design Build, we ensure your ADU is beautiful, functional, and code-compliant throughout Northern Virginia.

Schroeder Design Build ADU Cozy Exterior with Garden

Schroeder Design Build ADU Farmhouse Exterior in the Snow

Schroeder Design Build ADU Modern Clean Interior

Types of ADU Additions We Build

Detached ADU (DADU)

Known as a backyard cottage, granny flat, laneway house, or guest house, the Detached Accessory Dwelling Unit (DADU) offers independence and income potential without disrupting the flow of your main home. As a stand-alone structure, a DADU provides privacy and versatility in a beautifully designed secondary housing.

Attached ADU

An Attached ADU shares at least one wall with the primary residence. They’re often called in-law suites, home extension apartments, or bump-out ADUs. They’re especially popular among families caring for aging parents or looking to add a self-contained apartment without sacrificing backyard space.

Garage Conversion

For homeowners looking to maximize square footage while keeping costs in check, a garage conversion offers one of the most cost-effective ADU solutions available. By converting the garage into a living space, you acquire a garage apartment for extended family, renters, or flexible guest accommodations.

Attached Garage Conversion

An attached garage conversion allows you to repurpose the space into a garage apartment, accessible from inside your home or through a private side entrance. This option is ideal for those who want close proximity between the main residence and the new unit while staying within budget.

Detached Garage Conversion

A detached garage conversion offers the privacy of a backyard guest house with all the benefits of adaptive reuse. This option is great for multigenerational living, rental income, or private studio space that keeps the main house undisturbed.

Over-Garage ADU

If you want to preserve your existing garage while adding livable space, an Over-Garage ADU is the best of both worlds. Often referred to as a carriage house, apartment over garage, or second-story ADU, this solution maximizes your lot’s Floor Area Ratio (FAR) while maintaining covered parking.

Interior ADU Conversion

Sometimes, the best place to build is within your home’s existing footprint. Interior ADU conversions reimagine underused spaces into a basement apartment, attic ADU, or an internal in-law suite. Ideal for tight budgets or cold climates, these conversions offer a cozy, insulated solution without major exterior construction.

A Trusted Choice for ADU Design & Construction in Northern Virginia

As a second-generation, family-owned firm, deep roots in Northern Virginia bring more than local knowledge, they bring a shared understanding of the homeowners in this community. Familiarity with regional regulations, neighborhoods, and day-to-day living informs each remodeling project from start to finish, helping create spaces that feel comfortable, valuable, and truly at home.

i

Zoning Specialists

Local codes and permitting requirements are well understood, so your project is planned with compliance in mind from the beginning.



Turnkey Service

From the first design concepts to the finishing touches, every step is coordinated under one team.



Transparent Pricing

Clear communication about costs helps prevent surprises and keeps expectations aligned throughout the project.

ADU Design & Build Process

An ADU should be built with the same care and attention as the rest of your home. A structured design-build process helps ensure quality craftsmanship, thoughtful planning, and clear communication from start to finish. Here’s what that journey typically looks like:

Multiethnic couple handshake with consultant at home

Step 1: Feasibility Consultation

Your property survey and local zoning requirements (such as Arlington or Fairfax regulations) are reviewed to understand what’s possible on your lot.

Step 2: Custom Design & Budget Planning

3D renderings help you visualize the space, along with clear pricing so expectations stay aligned as the design develops.

Step 3: Permitting & Approvals

Paperwork is submitted to the county and inspections are coordinated, keeping the process organized and easier to navigate.

Step 4: Construction

Your ADU is built efficiently, with attention to quality, site cleanliness, and minimizing disruption to your property.

Step 5: Final Walkthrough

Before completion, every detail is reviewed to ensure the finished space meets high standards and feels ready to enjoy.

Schroeder Design Build ADU Backyard Shed

Ready to Start Planning and Build Your ADU?

An Accessory Dwelling Unit (ADU) is more than just extra space. It’s an independent living solution designed for the people who matter most. At Schroeder Design Build, we combine creative design with expert craftsmanship to deliver custom ADUs that are both beautiful and built to last in Northern Virginia.

Ready to create an ADU that supports your long-term goals? Let’s talk about your ideas. Schedule a no-pressure consultation today.

Frequently Asked Questions

Prefab versus Custom ADU, Which is Better?

The right choice depends on your priorities, budget, and long-term plans for your property.

A prefabricated ADU can sometimes offer a faster timeline and lower upfront cost, but design options are typically more limited. Because these units are built off-site using standard models, they may not always blend as naturally with your home’s architecture or lot layout.

A custom ADU, on the other hand, is designed specifically for your property. This gives you flexibility in placement, layout, materials, and appearance, helping the new space feel like a natural extension of your home rather than a separate structure. Custom designs also allow for better alignment with local regulations and how you plan to use the space over time.

What Can an Accessory Dwelling Unit Include?

An ADU is designed to provide everything someone needs to live comfortably and independently in a secondary living space. That typically includes a bedroom, bathroom, kitchenette, and a small living area. Some ADUs also include laundry for added convenience.

A custom ADU can go beyond the basics, too. Depending on space and goals, it might include a second bedroom, a home office, extra storage, or other features that support how the space will be used.

How Much Does a Custom ADU Cost?

Costs to build a custom ADU in Northern Virginia can vary widely depending on factors like size, design complexity, site conditions, utility connections, materials, and finishes. Because every property and set of goals is different, there’s no one price that fits every project.

For reference, many ADU projects in Virginia fall roughly into a broad range of about $150 to $450+ per square foot, with total project costs often averaging around the mid-$100,000s to low-$300,000s for fully custom detached units once design, permitting, utility upgrades, and quality finishes are factored in. In some cases, basic or smaller units may cost less, while larger or more highly finished ADUs can exceed these averages.

Keep in mind that these figures are averages and ballpark estimates — your actual cost could be higher or lower based on things like:

The size and layout of your ADU
Whether it’s attached, detached, or a conversion
Local permitting, utility extension, and site preparation needs
The level of finishes and appliances you choose
Structural or zoning constraints on your lot

For a more accurate idea of what a custom ADU could cost on your specific property, a personalized consultation is the best next step.

What is the Role of an How Long Does a Custom ADU Take to Finish? Designer in Interior Design?

The timeline for a custom ADU depends on the size of the project, design complexity, permitting requirements, and site conditions. In many cases, the full process — from planning and design through construction and final finishes — can take roughly 12 to 18 months.

Early planning, local approvals, and the level of customization all play a role in how quickly your project moves forward.

Do I Handle the Paperwork and Permits for My ADU Addition?

Permitting and paperwork can be one of the more complex parts of building an ADU. Working with a design-build team means those requirements are managed as part of the process, helping ensure the project meets local codes and moves through approvals more smoothly. That way, you can stay focused on the bigger picture while the details are handled in the background.