We are guessing that if you got this far through our site, you probably already know what an ADU is. Just to make sure we are all the same page, the acronym of ADU stands for Accessory Dwelling Unit - basically it is a second dwelling on a property that already has a main house.

Depending on where you live people may commonly refer to them by other terms such as guest suite, granny flat, guest house, backyard cottage, laneway suite, junior ADU, detached ADU, basement suite, casita, and many others. ADUs typically are full living units including bathrooms and kitchens, so they are a bit more involved than a backyard studio or office. They also are much different than Tiny Homes as ADUs have real foundations, can’t be on wheels, and typically are much larger. People build ADUs for a variety of reasons but some of the most common are creating housing for aging family members, downsizing after kids leave the house, income generator from long term or short term rentals (think Airbnb), while others add them for extra living space and as a place for guests to stay while visiting. ADUs can come in a variety of forms from fully detached structures (our preferred type of ADU), to attached additions or even renovations to interior spaces (think basement apartments). You can see many examples of ADU designs in our ADU Plans Store.

We could write thousands of words about the cost of ADU projects, and we have over the years. Truthfully, the cost of an ADU project really depends on hundreds of factors and it is hard to give an accurate estimate without learning more about the specifics of your project.

However, to give a straightforward answer, you can assume that the cost of building an ADU with current construction costs will be over $200,000. That being said, the ADU you are probably imagining for your backyard is more likely to come in at $250,000 or higher, maybe even over $300,000. We have worked on ADUs with construction budgets as high as $600,000. The biggest variables are site conditions (how easy/hard is it to build on your property - slopes are more $$$), complexity of the design (a simple box or more complex form?), and selection of materials and systems (do you want fiber cement siding, vinyl windows, and Ikea kitchen, or are you looking for more premium finishes like natural cedar siding, wood windows, and custom cabinets?).

Our ADU budget advice:

If you want a truly beautiful and sustainable project you probably should budget between $300,000 and $500,000 for your ADU. This will get you a project that uses premium materials, and high performance systems; one that you will be proud of, will be durable, and will add a lot of value to your property. We have found that ADUs are great investments and you recoup the cost of building through rental income, increased space for your family, and increased property values.

We understand that those numbers aren’t attainable for everyone, and may not be the right budget for a rental accessory dwelling unit. Also consider that the cost of construction varies a lot based on where in the country you live. The prices above are rough guidelines to consider as you plan for your project. We have designed simple, functional, and affordable ADUs for under $200,000 and luxury designs for clients who didn’t have a budget. We always strive to deliver projects to meet the needs of our clients.

The first step is to find out if your city or municipality allows Accessory Dwelling Units (ADUs). Some states, like California allow ADUs statewide. Oregon and Washington also have laws that are very supportive of ADUs across the state. However, check with your local building department to determine you local rules.

If they are allowed, you'll need to learn about the regulations surrounding them - for example, minimum size requirements, lot coverage limitations, height restrictions, and setback rules. For instance, in California ADUs have side and rear setbacks of 4' consistently, and you should factor in 6’ to 10' separation from existing structures.

You'll also need to choose a location on your property for your ADU and develop a site plan. Once you've done your research and found a suitable spot on your property, you can begin planning your project.

If you're not sure where to start, we offer consultations for those who want to ask questions. This is a great way to talk through the best path to meet your needs. Whether it is a custom design for those who are looking for a unique and luxury ADU solution, or pre-designed ADU plans that can save you time and money, a consultation can help you start the project off right and ensure you are on the best path forward.

ADU plan sets are a great way to speed up your ADU project. They can save months of time when compared to a custom design ADU approach. However, there will be some additional steps you will have to take before you can submit the design for permit approval.

Plan sets are generic designs and don’t include site specific information. You will need to develop a site plan showing the unique aspects of your property including existing structures, topography, property lines and setbacks, the location of the proposed ADU, utility connections, and other site specific information.

In most jurisdictions you will also need to get structural engineering drawings and calculations. You can share the purchased ADU plans with a local structural engineer who will develop the structural details, calculations, and framing plans that meet your local requirements.

In California you will also need a Title 24 report showing that the ADU meets building energy requirements before you can submit for permitting. There are many companies who can assist with creating this state required report. Although Title 24 is specific to California, many other states have similar requirements. Please check with your local building department to get a list of all the required drawings, forms, and information.

We also recommend that you hire a local designer, architect, engineer, and/or general contractor to assist with the permitting process and help with any revisions you may want or are needed to receive permit approval. Permitting can be tricky, and having an expert on your team to help facilitate the approval can be a big advantage.

Although ADUs are smaller in size than a custom home it doesn’t mean they take a lot less time to design. There are still lots of decision to make when doing a custom ADU project. We typically recommend scheduling about 6 months for the design phase (all the work prior to submitting for permitting). If you are able to make quick decisions or know what you want coming into the project, it can move quicker. But based on over 60 completed ADU projects we have worked on, the average ADU design process tends to take around 6-months.

This is a place where balancing schedule vs. getting a custom design could lead you to consider purchasing a pre-designed ADU plan. Starting with one of our pre-designed ADU Plans could save 4-5 months of work and thousands of dollars in fees when compared to a custom design. Plus with our Modern ADU Plans you can still get great design that is affordable, with a range of options that can meet almost any needs or work on most properties.

Permitting will be required for your project and this too can vary greatly from project to project. Each town, city, county and state has different permitting rules, regulations, and processes. In Portland, Oregon permitting typically takes 3-4 months. Seattle may be 6 months or more. Some cities in the San Francisco Bay Area have permitting processes that could take almost a year or more. Crazy, I know! Smaller towns and more rural areas often permit projects a lot faster. Plus many building departments are understaffed due to the lasting effects of the Covid pandemic. It really varies and is hard to predict.

Adding the construction phase to the ADU project schedule would add about 6-9 months on top of the design work and permitting process. This would make a typical ADU project take over 1-year from start to finish. I’d recommend planning for 18 months for a custom ADU project and probably around a year if starting from a predesigned ADU plan.

We sure do think so. In fact, we have added an ADU to a house we owned and would have added additional ADUs if the local regulations allowed it. Generating rental income was a great ROI for our ADU.

Of course the answer to this question depends a lot on your situation and finances. In general, ADUs are great investments in that they can generate income as a rental unit or save you thousands of dollars a month on costly housing for aging family members or for yourself. On top of rental revenue or savings on housing costs, ADUs also increase your property value if or when you decide to sell your property. Often the increase in value to your property is more than the cost of constructing the ADU. They are well worth the investment and can both generate passive income as well as increase your home value.

Although our plans are predesigned, and the true efficiency and cost savings is sticking with the plans as-is, there are times where small edits may be desired or required. Our team can make revisions to the plans and will estimate the amount of work that would be needed based on your requested changes and then put together a fee estimate for the scope of work. We have a minimum fee of $1,250 to make edits to the design drawings, and the final price will be determined by the complexity of the requested edits. The time needed to make revisions can vary greatly. For most changes you should expect to budget between $1,500 and $3,500. Occasionally revisions could cost more, as even small changes can take a significant amount of time to revise the drawing set.

As you consider potential changes, know that it is easier to change interior elements like kitchen layouts or moving interior walls. Changes to the exterior walls, roof, foundation, windows and doors, and other elements that could affect the structure and building envelope will cost more to revise.

To begin this process, purchase the plan set you want to start from and then let us know you are wanting to make some revisions. We will either converse by email or schedule a call to discuss the requested changes. We then put together a price for the work to complete the revisions. This price will be the fixed price for the defined scope of work and we will send an invoice for this amount to be paid in full prior to beginning work.

Fantastic! You are ready to move forward with your Accessory Dwelling Unit project. Here are our recommendations for your next steps:

If you are looking for a pre-designed ADU plan, check out our available options here: Pre-designed ADU Plans

Pick out the design that best meets your needs, purchase the plans, and then work with a local designer, builder, and/or engineer to work through the permitting process for your location and build the new ADU. Once you purchase the plans if you want some revisions made to the design we can connect you with our drafting service.

If you would like a custom designed detached ADU for your backyard there are a couple options for your next steps. First, you can download our ADU Investment Proforma spreadsheet on our downloads page. This tool can help you establish a budget and see the return on your ADU investment. Next, you can contact us to share more about your goals and ideas. Of note, at this time we are only working on custom designs for detached ADUs. If you are looking for a garage conversion or basement renovation for your ADU, we can refer you to another design team to assist you. However, if you are interested in a new construction, detached ADU, especially sustainable or high performance ADUs, we are the team for you.

Every property is different and every town and city has their own rules and regulations regarding ADUs. Zoning laws, setback requirements, topography, site features like trees or walls, and many other elements can affect where an ADU can or should be built on your property. The Site Plan shows all of the various features of your property and locates all existing structures and shows the proposed location for the ADU.

This drawing is highly unique to each site and must be created specifically for your project. It is best to hire a local designer, drafter, or other professional to assist with the creation of a site plan so that it addresses all of the local rules and requirements of the building department, planning department, fire department and and other departments that review drawings before they are approved. It is very difficult for this work to be done remotely so we recommend you engage a local professional to assist with this scope of work, unless you are confident you can handle it yourself.

Once a purchase of an ADU house plan is made, you will have access to download a PDF of the selected ADU design drawings (we are currently working on adding CAD drawings to the downloadable product). Specifically, the drawing set will include a cover sheet with a view of the ADU design, a Notes and Terms & Conditions sheet that dictates the terms you agree to by using our plans, floor plans showing the dimensions of the overall design and the interior layout, Roof Plan showing a top-down view of the building, elevations of the ADU exterior, building sections cutting through the ADU, sectional and plan details needed to describe the construction details and assemblies, kitchen and bathroom plans and interior elevations as needed to describe the design intent.

Yes. When purchasing one of our ADU plans you are given a link to download a PDF of the drawing set (ADU blueprints). Upon request we can send a .zip file with CAD drawings of the ADU house plans for you to make revisions to the drawings to meet local codes and regulations and work with a local structural engineer, designer, or other consultants.

Congratulations on being ready to purchase an ADU house plan. Since every site is unique and each local jurisdiction has their own set of rules and regulations, you will need to do the due diligence to make sure the design you purchase is allowed and will work on your property. You also need to get structural engineering and/or engage other consultants to provide any information your local regulations require. We also recommend that you hire a local designer, architect, engineer, and/or general contractor to develop the site plan, to assist with the permitting process, and help make any design revisions you may want (although you can also contract with us to make simple design changes.

Once the casita design has been permitted and approved by your local building department, you will also need someone to build the ADU. Although you could DIY it, we find that most people would be better served by hiring a licensed General Contractor to construct the ADU. A good builder can really help make your project a success.

Construction costs for ADUs vary a lot depending on the location, and the local material and labor costs at the time of construction. You also can affect the overall cost by selecting more affordable or more expensive products and systems, or doing some of the construction work yourself. However, all of our ADU designs have been built for a construction cost between $200,000 and $400,000. To get a more accurate estimate of a specific design feel free to reach out and tell us which ADU design you are looking at and we can give some more specific cost information. Additionally, we recommend talking with a local builder to put together a cost estimate once you select an ADU plan.

Financing an accessory dwelling unit (ADU) project can be a significant undertaking, but with careful planning and understanding of your options, it can become a viable and rewarding investment. Here is a short guide to help homeowners navigate the world of ADU financing.

Evaluate Your Financial Resources: Before diving into an ADU project, assess your financial resources to determine how much you can comfortably invest. Consider your savings, equity in your home, and any available lines of credit. Additionally, research local incentives and financing programs specific to ADUs, as some regions offer grants, low-interest loans, or tax incentives to encourage ADU construction. Understanding your financial capabilities and potential assistance will help you set a realistic budget and explore appropriate financing options.

Explore Loan Options: There are several financing options available for ADU projects. One common approach is a home equity loan or line of credit, leveraging the equity in your existing property to fund the ADU construction. These options typically offer competitive interest rates and longer repayment terms. Another option is a construction loan, specifically designed for home improvement projects. Construction loans provide funds in stages as the project progresses. Additionally, some homeowners may choose to refinance their mortgage, combining the ADU project costs with their existing home loan. Exploring different financing options will help you find the best fit for your financial situation and goals.

Consult with Lenders and Financial Advisors: It's crucial to consult with lenders and financial advisors who specialize in ADU financing. These professionals can guide you through the loan application process, explain the terms and conditions, and answer any questions you may have. They can help you understand the implications of different financing options on your overall financial well-being and ensure that you make informed decisions. Engaging with experts in ADU financing will provide valuable insights and increase your chances of securing the best financing terms.

Each homeowner's financial situation is unique, and it's important to consult with professionals to determine the best course of action for your ADU project. By diligent when evaluating your resources, exploring financing options, and seeking expert advice, and you'll be well on your way to successfully financing your ADU project and enjoying the benefits of this valuable addition to your property.

As an ADU design expert, I understand the importance of creating rental ADUs that maximize the potential for both functionality and aesthetics. When it comes to designing a rental ADU, there are several strategies that can greatly enhance its appeal to potential tenants and be a great financial investment for you.

An open floor plan can create a sense of spaciousness and versatility, allowing tenants to personalize the space to their needs. Additionally, incorporating ample storage solutions throughout the unit can help optimize the limited square footage, providing tenants with practical and organized living spaces. Including outdoor space to expand the living area is a great strategy to make the smaller sized home feel more spacious. Lastly, integrating eco-friendly features such as energy-efficient appliances and sustainable materials not only benefits the environment but also adds to the desirability of the rental ADU. By implementing these design strategies, landlords can create rental ADUs that stand out in the market, attract high-quality tenants, and generate sustainable income for years to come.

Tons of people have come to us asking for garage conversion ADUs over the years, and the majority of the time my recommendation is to tear down the garage and build a new detached ADU. Doing an ADU garage conversion can be rather expensive for what you end up with, and probably won't get you what you are looking for.

Sometimes conversions actually cost more than building new considering you would most likely have to redo the foundation footings and concrete slab, plus add sewer and water to the right places. Working within an existing structure makes all of this a lot more complicated and thus costly.

Also, most garages were not built to meet current building codes for housing so require a lot of rebuilding and adapting to meet the codes as well as be a nice place to live. Plus working within an existing footprint can be very limiting. You may get a higher return on investment by building new and going with a larger ADU than trying to squeeze it into the footprint of an old garage.

And if you do build new, you could potentially put an ADU over a new garage, like we did in The Overhang ADU. Having a two bedroom rental over a 2-car garage is a great way to preserve some private off-street parking while generating rental income, or downsizing.

We have designed many two story ADUs, including ADUs over garages, so it is definitely possible. There may be local height restrictions that affect these sorts of ADUs, so check your local zoning codes to learn about any limitations. Even with height limits it still may be possible to build two stories with some create design solutions.

We designed a two-story ADU to fit within a 16’ height limit by semi-submerging part of the ADU. We created an L-shaped plan with the living and kitchen areas on one wing built on-grade. We then dug down two feet for the other wing and stacked two bedrooms, one over the other. This created a split level section of the design allowing for two stories to fit under the 16’ height limits. Create solutions like this is why you may want to consider going with a custom design rather than with the pre-designed ADU options. It allows for some creativity and unique solutions to your specific needs and challenges. Reach out if you would like to talk with us about a custom designed ADU or laneway suite.

If you use a similar strategy as described above, and dig down to have a semi-submerged room, waterproofing will be super important. Otherwise you could get moisture penetration and mold problems. Make sure you work with your builder to develop a robust waterproofing detail for the submerged area of your ADU.

Another consideration is that excavation and hauling off dirt can get quite pricey, thus making digging down a relatively expensive endeavor. Make sure that the benefits of digging down outweigh the added costs.

Accessory Dwelling Unit, or ADU for short, is the most common technical term for the concept of having additional living units on a property with a main house. There are many other common names for these project types, however. In fact, many cities or regions have developed their own common names. For instance in Vancouver and Toronto, Canada they are often called Laneway Suites or Garden Suites. Seattle often refers to them as DADU, or detached accessory dwelling unit. Across California ADUs can also be called casitas. I have heard them referred to as in-law suites, granny flats, or simply guest houses. In many places, ADUs that are located within the main house structure are often called JADU, or Junior Accessory Dwelling Unit. Despite the large range of names, they all pretty much mean the same thing. An ADU is a secondary living unit typically smaller or secondary to the primary residence.

Really this is just a nomenclature difference. Before computers, design drawings were done by hand and blueprints were a technique to reproduce the design drawings - basically make copies of the original hand drawings. When computers and digital printers became prevalent we not longer needed to copy the originals. Instead, we just print multiple copies from the digital file. However, the term blueprint didn’t fade as fast as the technology evolved. Thus you still may hear people refer to ADU design drawings as ADU blueprints.

Looking forward a bit, I anticipate all physical drawings becoming less and less common. We sell digital drawings and most building departments are transitioning to accepting PDFs, or other digital files for review in the permitting process. Design drawings are still often printed for the General Contractors to use when building an ADU project, but even that is starting to shift. We have worked with many builders who use iPads and other technology on site to reduce the need for printed drawings. It will be interesting to see how much longer paper copies of ADU design drawings will be used, rather than designers sending digital files or BIM models to the contractors.

Some rental ADU design strategies include maximizing space efficiency through open floor plans and multifunctional areas, incorporating ample natural light to create inviting living spaces, ensuring privacy for both the main house and the ADU, providing separate entrances and outdoor spaces for tenants, and using high-quality materials and finishes to attract and retain tenants and reduce maintenance costs. Additionally, considering the needs of potential renters and local rental market trends can help inform design choices that make the ADU more appealing and marketable. For instance, we would recommend two bedrooms an one bathroom as the ideal for a rental ADU. The goal is to develop an ADU that can generate positive cashflow on a monthly basis.

We believe the easiest and highest quality ADUs are detached, new construction projects. Having space between the ADU and the main house provides privacy, allows for flexibility in the future if you decide to divide the lot or sell each unit separately, and allows the most flexibility in terms of design and layout. We also find that new construction gives you the highest quality project and allows for a sustainable, high-performance building. We don’t recommend garage conversions and don’t do renovations or basement conversions either. We focus specifically on new construction, detached ADUs.

Selling digital design products allows us to service clients around the world. However, most of our clients are in locations in the USA and Canada that have legalized ADU projects. ADUs are particularly popular in states like California, Oregon, and Washington, although other locations have been working on legalizing and incentivizing ADUs. New York State (and New York City) have recently passed laws to promote ADUs, cities across Texas have seen a rise in ADUs. Idaho, Minnesota, Massachusetts, and many others have also been working on promoting ADUs as one way to help address housing issues.

Our designs are meant to work almost anywhere, and we can work with you to customize the designs to meet your local codes and regulations. Regardless of where you live, we can help you realize your ADU dream.