house planning and architectural drawings on a table, with a small model house, key, and protractor laying on top of them

Working on a floor plan is a vital step towards getting an Accessory Dwelling Unit (ADU). Whether you are building an attached or detached ADU or simply converting a part of your existing home, you will need ADU plans.

To Buy or Design ADU Plans?

There are plenty of ADU plans that you can find on the internet. But is it really a good idea to buy those plans and not design one yourself? 

Well, that entirely depends on your needs and requirements.

Here are some reasons why you should buy ADU plans and some reasons why you should design them. 

Reasons to Buy ADU Plans

The first step of any ADU project starts with planning and design, which can be quite challenging and complicated.

By buying a pre-made plan, you can simplify this step and free yourself from the stress that comes with this task. 

Moreover, purchasing a stock plan from the sites listed above can help you save hundreds of dollars and weeks of waiting if you were to hire a company to draw a custom plan. 

Additionally, most companies listed below offer ADU plans that adhere to both state and municipal codes, meaning you don’t need to worry about getting approvals. 

Reasons to Design ADU Plans

Even though there are plenty of plans to choose from online, you might not be able to find one that fits your specifications.

For instance, a snug place for your parents to live has different requirements than a place for a family with young children.

Before buying an ADU plan, think about your needs and constraints first.

If you are not able to find a ready-made plan, it might be wise to design one yourself to ensure that all your requirements are effectively met. 

Where to Find ADU Plans?

If you have limited knowledge of the industry, finding ADU plans can be a daunting task.

However, if you’ve carefully considered your specifications, finding the right choice from the top sites for ADU plans listed below should be a breeze. 

1. ADU Building Plans

Over the past two decades, ADU Building Plans has designed hundreds of residential and commercial projects.

It helps clients find “ready-made” plans that meet their needs and offer all the resources needed for building a new ADU. 

Exterior rendering of a ADU Building Plans ADU
ADU CONSTRUCTION PLAN #LD-1906. Courtesy of ADU Building Plans

The company aims to make the once-complex and expensive process of designing your ADU affordable and simple.

It offers customizable and functional plans and guides you through the design process so that you can build the ADU of your dreams. 

What We Like About It

ADU Building Plans currently has 55 different ADU plans for you to choose from.

The company offers design and construction plans for different styles, including contemporary, traditional, and modern, in single- and two-story builds. 

An overhead rendering of the interior of an ADU Building Plans' ADU
A floor plan of a 1-bed and 1-bath home. Courtesy of ADU Building Plans

Plans start at $49 and go up to $149.

Thus, you will surely find a plan that fits your budget and requirements. All plans for purchase come with a complimentary cost-to-build form for collecting contractors’ bids. 

2. Architectural Designs

Architectural Designs offers house plans from more than 200 designers and architects.

The family-owned business has been selling home plans to homeowners and builders all over North America (and even internationally) for generations.

Designs include everything from ADUs and starter homes to fancy luxury houses.

An exterior front view rendering of an Architectural Designs ADU
This cabin-style rendering is a two-story vacation home. Courtesy of Architectural Designs

What We Like About It

Architectural Designs offers ready-made plans for purchase. However, if these designs don’t match your needs, you can modify them to suit your specific requirements.

The company allows you to choose from more than 300 floor plans ranging from 298 sq feet (27.69 sq meters) to 7,164 sq feet (665.56 sq meters) for a variety of building types, including single-family homes, garages, pool houses, offices, and sheds.

Interior fitness room view of an Architectural Designs ADU
A sample interior of a home gym. Courtesy of Architectural Designs

You can filter your choices according to the number of bedrooms, bathrooms, and floors you want in your home.

In addition, you can even choose according to the type of foundation, exterior walls, and garages you want.

What’s best is you can also add special features such as a loft, home office, or elevator. 


HOUSEPLANS offers a range of ready-made architectural designs.

Since 2004, the company has helped thousands of people find their dream home layouts.

Interior living room rendering of a HOUSEPLANS ADU
Plan No. 836420 is dubbed as part of the “Charming Tiny Home” plans. Courtesy of HOUSEPLANS

Its goal is to provide pre-designed plans to help clients save money and time.

Many professional home builders depend on HOUSEPLANS for the right floor plans at the appropriate price. 

What We Like About It

HOUSEPLANS has almost 100 ADU plans and designs for you to choose from, including garage apartment plans, granny pods, and more. 

Exterior front view of a HOUSEPLANS cabin ADU
A cute 1-bed cabin vacation home. Courtesy of HOUSEPLANS

The size of these plans ranges from 192 sq feet (17.84 sq meters) to 2,313 sq feet (214.88 sq meters) and are priced from $305 to $1,820.

You can customize your choice according to the number of beds, baths, stories, and garages you want. 

Along with a low-price guarantee, the great thing about HOUSEPLANS is it offers free ground shipping – within the continental US – on plans. 

4. ROST Architects 

Based in Southern California, ROST Architects is a licensed design and architectural firm committed to the philosophy of environmental sensitivity, clarity, and simplicity. 

Exterior front view of a ROST Architects ADU
Villa A is a 1-bed and 1-bath 800-square-foot modern home. Courtesy of ROST Architects

It creates site-specific architecture that integrates into the site’s local cultural and environmental conditions.

The company aims to integrate technology at the forefront of sustainability with every project while preserving a high degree of attention to detail and design. 

ROST Architects has also developed close relationships with local contractors, engineers, and builders who share similar visions for the built environment and bring projects to life. 

What We Like About It

ROST offers ADU designs for studio houses, one-bedroom, and two-bedroom homes. 

You can also buy ROST Architects’ preliminary site analysis package to see the size, location, architectural size, and orientation it recommends for your ADU blueprints. 

We like this company because its team will review your property and offer various options for your ADU plans, accounting for your individual site circumstances, relevant codes, and your desired use of the structure.

Interior living room view of a ROST Architects' ADU
The interior of Villa A. Courtesy of ROST Architects

It will present the advantages and drawbacks of every option so that you can make the right choice.

Depending on your level of satisfaction, you can either continue with the project or discuss alternative options. 

5. Modern ADU Plans

Modern ADU Plans offers a range of plans that you can use to convert your backyard into an oasis of excellent design.

These plans allow you to generate rental income, increase your space, or bring your family together in a beautifully designed ADU. 

Exterior front view of a Modern ADU Plans ADU
The Shift ADU is integrated with Scandinavian and modern design elements. Courtesy of Modern ADU Plans

What We Like About It

Modern ADU Plans has a number of different ADU plans, all completely different from one another.

For instance, they have the Farmhouse ADU, the Home Office ADU, the Suncatcher ADU, the Butterfly ADU, and the Stilts ADU. 

Interior bathroom view of a Modern ADU Plans' ADU
True to their name, they put modern fixtures at the top of their list. Courtesy of Modern ADU Plans

All plans include a cover sheet, terms and conditions document, floor plans, a roof plan, elevations, building sections, sectional and plan details, enlarged kitchen and bathroom plans, and interior elevations. 

However, if you want something beautiful and unique, you can opt for their custom-designed ADUs that are developed to your preferences and specifications.

You can also use their fixed price model to determine exactly how much you need to pay for the design work. 

6. True Built Home 

True Built Home was founded by Lewis Mann when he realized that certain home builders focused on overselling rather than actually building homes.

Thus, he focused on building the best quality homes at the lowest cost. 

Exterior front view of a True Built Homes ADU
The Keyport Home Plan is 707 square feet of living space. Courtesy of True Built Home

All in all, True Built Home aims to provide the best value homes with quality products rather than offering the cheapest square foot cost. 

What We Like About It

True Built offers 13 different ADU plans, ranging from 495 sq feet (45.99 sq meters) to 1,199 sq feet (111.39 sq meters).

You can either use the ready-made plan for building or get a custom design that suits your needs.

7. SnapADU

Located in San Diego, SnapADU is an excellent place to find ADU floor plans in the US.

The company has dozens of build-ready ADU plans for different needs. From one to five bedrooms and two-story guest suite floor plans, you’re sure to find an option that aligns with your requirements from this company.

A rendering of a white 2-storey ADU plan from SnapADU
You can fine-tune the design with help from their in-house architects. Courtesy of Snap ADU

If you choose the two-story plan, you can reserve the ground floor for living and the first floor for bedrooms. You can also have the dining area on the ground floor. 

Even if you can’t find a perfect match, the company’s architects can customize the existing plans based on your specifications, like having large windows for natural light penetration.

The company guarantees top-notch project management through its holistic, specialized, and savvy architects. Therefore, you can rest assured of getting an ADU plan that will transform your dream into a reality.

What We Like About It

We like the fact that the company matches the exterior of the ADU to the client’s main home. Therefore, your compound will have structures with almost similar features.

Additionally, you can work with the company’s team to customize your guest house based on its interactive 3D floor plan tool.

Finally, SnapADU produces all its plans in-house. This is crucial for quality control since all these plans are curated to facilitate ADU construction permitting.

Last Few Words

ADUs are an excellent way to maximize your usable area by having additional living space, increasing your property’s value, and simply doing more with what you have at your disposal. 

These units come in handy if you want to accommodate your extended family because they incorporate a minimalist design. 

We believe it is best to take the burden off your shoulders by using the designs the companies listed above offer, as they will surely transform your space.

The best part is that these plans are ideal for both attached and detached ADUs.

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