What is an ADU?

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.

How much does it cost to build an ADU?

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?).

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.

How do I start an ADU project?

The first step is to find out if your city or municipality allows Accessory Dwelling Units (ADUs).

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.

How do I get my pre-designed ADU ready for permits?

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.

How long does it take to design an ADU?

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 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 Los Angeles, California for example permitting typically takes 4-5 months.

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. We recommend planning for 18 months for a custom ADU project and probably around a year if starting from a pre-designed ADU plan.

Is an ADU a good Investment?

We sure do think so. 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.

Can I make revisions to the pre-designed ADU’s?

Although our plans are pre-designed, 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 $4,500. 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. We will make sure to give you a $500 credit, in the case you hire us to complete the permit process.

I’m ready to build an ADU. How do I get started?

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. 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 ADU, either detached, attached, located on a Single Family Residence, or Multifamily Building, please contact us so we can assist you better.

Why do I need a Site Plan for my ADU project?

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.

What is included in the download file from the pre-designed ADU’s?

Once a purchase of an ADU house plan is made, you will have access to download a CAD of the selected ADU design drawings (we are currently working on adding PDF drawings to the downloadable product). Specifically, the drawing set will include the 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 and building sections cutting through the ADU. Please contact us with proof of purchase so we can email you the PDF set and renderings as well.

I’m ready to buy one of the pre-designed ADU plans. What else will I need?

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 design changes).

Once the ADU 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.

How can I finance my ADU project?

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. Be 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.

Can I convert my garage into an ADU?

At least in the state of California, garage conversions are allowed to become ADUs. It is a cost-effective way, in most cases if the existing building is in good condition. Feel free to contact us if you have any questions on garage conversions to ADUs.