adu construction

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Maximizing Your ADU Budget: Download Our Free ADU Budget Worksheet Today

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If you are considering building an Accessory Dwelling Unit (ADU) but feeling overwhelmed by the costs involved, we sympathize. ADUs are significant investments even though they are small houses. There is also a lot of misleading information out there on ADU Facebook Groups, ADU blogs, and other sources. Budgeting for an ADU project can be a daunting task, and can get complicated, which is why we have created a comprehensive ADU Budget Worksheet to help you plan effectively and maximize your budget.

Why You Need an ADU Budget Worksheet

Your ADU project's budget is crucial to ensure that you stay on track and avoid financial surprises along the way. Planning early and accurately can help you save costs and avoid mistakes on your ADU build. Our ADU Budget Worksheet is designed to assist you in estimating costs accurately, identifying potential expenses, and helping you make informed decisions throughout the construction process. It is a guide that you can use early on in the planning process, but also set up to help you track the actual costs and compare them against your budget throughout the ADU design and construction process.

What Does Our ADU Budget Worksheet Offer?

Our free ADU Budget Worksheet includes detailed sections for all aspects of your ADU project budget, such as:

  • Construction Costs: Estimate expenses for materials, labor, permits, and more.

  • Design and Planning Fees: Include costs for architectural plans, engineering, and other design-related expenses.

  • Utility Connections: Budget for water, electricity, and gas connections.

  • Interior Finishes: Plan for flooring, fixtures, appliances, and other interior design elements.

  • Exterior Finishes: Estimate costs for siding, roofing, landscaping, and other exterior finishes.

  • Contingency Fund: Allocate a percentage of your budget for unforeseen expenses.

How to Download Our Free ADU Budget Worksheet

Getting your hands on our ADU Budget Worksheet is easy! Simply click the download link to the right to access this essential tool for your ADU project. Take the first step towards a well-planned and budget-friendly ADU construction process today.

Don't let financial concerns hold you back from realizing your ADU dream. Download our free ADU Budget Worksheet now and pave the way for a successful and cost-effective ADU project. Download now and start building your dream ADU with confidence!

Remember, proper budgeting is the key to a stress-free ADU construction experience. Let our ADU Budget Worksheet be your guide as you embark on this exciting journey.

Your ADU budget worksheet is filled out and you are ready for the next steps?

There are a few ways you can move your project forward after you work through the budget. You can hire a designer to help develop a custom designed ADU, purchase a pre-designed ADU plan, or talk to an ADU expert to discuss your ideas and develop a plan. Luckily Modern ADU Plans offers all of these options to help homeowners like you achieve your ADU goals.

There are three convenient buttons on the right side of this blog, each one offering you a way to take the next step towards your ADU.

Next Steps for your ADU Project:

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Your Guide to Hiring a General Contractor for Your ADU Project

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Building an Accessory Dwelling Unit (ADU) can be an exciting way to add living space, generate rental income, or create a home for aging family members. But navigating the construction process can feel daunting, especially when it comes to finding the right general contractor (GC). This crucial decision will significantly impact your project's success, so careful consideration is essential.

This guide equips you, the homeowner, with the knowledge and steps to confidently find a general contractor who aligns with your vision, budget, and timeline for your ADU project.

Pre-Contractor Prep: Setting Yourself Up for Success

Before diving headfirst into contractor searches, some groundwork on your end will streamline the process and empower you to ask informed questions during interviews.

  • Solidify Your ADU Vision: Do you already have a design complete or have a specific design idea in mind? Typically a GC will want to see a rough design to be able to respond to. Think about the form of the ADU, its size, functionality (studio, one-bedroom, etc.), and any special features you desire. These all will affect the cost to build and the complexity of the construction process. Having a basic layout complete or browsing online inspiration boards like Pinterest or Houzz can be helpful. Or rely on drawings and images from your designer to set the direction.

  • Know Your Local Regulations: Building codes and permitting processes vary by municipality. Research your local ADU regulations to understand feasibility and potential limitations. This knowledge will equip you to discuss the project's regulatory framework with potential contractors. Again, it is probably best to have a designer on board as you do this prep work prior to beginning your search for the ideal builder.

  • Establish a Realistic Budget: Research average ADU construction costs in your area. Consider not just the build itself, but also architectural plans, permitting fees, and potential utility upgrades. A realistic budget will guide your contractor selection and keep your project on track financially. It is also best to not just use cost per square foot calculations that you find on the internet. They are rarely accurate and very misleading. Instead ask around and find total project costs for similar projects. Walk around your neighborhood and find properties that have ADUs and ask their owners what the total project cost was. This will be the best way to get some accurate information. Your design team should also be a great resource to share information on construction costs of similar project.

Finding Your Contractor: Where to Look and How to Narrow Down Options

  • Talk to Your Designer: chance are you hired a design team because they have some experience on similar projects. Leverage that experience by asking them to recommend contractors they have worked with in the past that have successfully completed projects on time and on budget. The design team will probably have a handful of go-to contractors they like working with and would recommend for your project.

  • Leverage Your Network: Talk to friends, family, and neighbors who have built ADUs. Personal recommendations are a goldmine, offering valuable insights into contractor performance and potential red flags. Ask them about the outcomes, the communication style, what happened when there were bumps in the road. This sort of insight will be a great way to assess if a contractor is worth interviewing for your ADU project.

  • Online Directories and Review Platforms: Websites like Houzz, the National Association of Home Builders (NAHB), and the Better Business Bureau (BBB) allow you to search for licensed contractors in your area and view customer reviews. There are probably local directories in your area as well. Read reviews, peruse company portfolios and select the companies that have worked on similar projects and share your values.

  • Specialty ADU Contractors: Consider companies specializing in ADU construction. Their experience with ADU-specific regulations and construction techniques can be invaluable and help avoid costly mistakes.

Qualifying Potential Contractors: The Interview Process

Once you have a shortlist of potential contractors, it's time for background research and in-depth interviews. Here's how to effectively assess each candidate:

  • Licensing and Insurance: Verify the contractor holds a valid license in your state and has adequate general liability and worker's compensation insurance. Ask for copies of these documents. Check with the National Association of Home Builders (NAHB), and the Better Business Bureau (BBB) to verify the information and see if there are any complaints or legal issues with the company.

  • Experience with ADUs: While general construction experience is valuable, prioritize contractors with a proven track record of successful ADU projects. Ask to see examples of their past work, ideally in your area and with similar ADU styles.

  • Communication Style: A comfortable working relationship is key. You will be working with this team for many months in a stressful environment. Assess the contractor's communication style during the interview. Are they responsive, clear, and patient with your questions? Ask to speak with the project manager or any team member that will be leading the project if it won’t be the business owner or person you interview during the selection process.

  • Project Timeline and Budget: Discuss your ADU vision, budget, and desired timeline with each contractor. Get detailed quotes outlining the scope of work, materials, and projected costs. There will be more about how to compare bids below. Be wary of quotes significantly lower than the average – they could indicate cutting corners or missing items that will be added later.

  • References: Request a list of references from previous clients. Contact these individuals to get firsthand accounts of the contractor's work ethic, communication, and problem-solving skills. Ideally these references are people who built similar types of projects.

Beyond the Interview: Additional Considerations

  • The Contract: Before signing any agreements, have a lawyer review the contract. The contract should clearly outline the project scope, timeline, budget, payment schedule, and change order procedures. Don't hesitate to ask questions and ensure you are comfortable with all the terms before signing.

  • Permits and Inspections: Inquire about the contractor's experience navigating the ADU permitting process in your area. Although your design team may be leading this process, or perhaps you are taking it on to save costs, there will be times when the contractor may get involved. Working with a an experience team can help navigate the complexities of permit review and save time.

  • Dispute Resolution: The contract should outline a clear process for resolving any potential disputes during construction.

Building Trust and a Strong Partnership

Finding the right general contractor is an investment in the success of your ADU project. By thoroughly vetting candidates and prioritizing clear communication, you can build a strong partnership with your GC and navigate the construction process with confidence.

Bids

When you ask GCs that you are interviewing for estimates or bids for the project, you will not be getting them in a standardized format. Each construction company handles bids differently. Your job as the homeowner is to review the bids when they come in and develop a process to interpret them so you can compare apples-to-apples. If you are unsure how to do this, ask your design team to help.

Often this means setting up your own spreadsheet or document and reorganizing the numbers you get from the builders so it is easier to compare across companies. The goal is to not just look at the total cost at the bottom of the bid, but to look at each line item to see if there are any outliers or red flags that need a more thorough review.

For example, if one company has the window package at $30,000 and another only shows it at $10,000 that is red flag. You will want to ask more questions of those companies to clarify how they calculated their numbers to make sure they didn’t make a mistake.

By understanding how a company calculated their costs you can build trust with that team. This also means that you don’t always want to go with the lowest bid. The lowest bid might mean they are missing items, didn’t take the full cost into consideration, and may have a lot of costly change orders throughout the project.

In fact, we rarely recommend hiring the cheapest builder.

Specific Questions to Ask As You Interview Builders:

How big is your team?
The size of the General Contractor’s company can shine a light on their resources, capacity, and organization. Often a larger company would have a dedicated project manager to lead your project, may be able to handle more complex projects, and may have in-house teams perform some of the work rather than subbing it out to other companies.

That doesn’t mean bigger companies are better for your project though. Small contractors offer some advantages as well. You might be working directly with the company owner, getting a more personalized service. Or they may be more affordable with less overhead expenses.

How many projects of a similar type and scale have you done recently?
You don’t want to hire a company that works on large multi-million dollar estates, or commercial buildings, to build a small ADU project. Their team won’t have the right experience. You want someone familiar with the type of project you are building so they can bring lessons learned from other projects to your build.

How many recently completed projects have come in on or under budget?
You want someone who has a track record of managing the construction budget. No one likes cost overruns or being surprised part way through the build with expensive change orders or requests for additional payments. Ask for case studies showing they can keep your project on budget. The answers to this question should reflect the companies ability to manage their team, the schedule, and the execution of the project.

How many recent projects have come in over budget?
You want to know if projects have come in over budget and then ask why. There are many reasons a project may go over, and it isn’t always the contractor’s fault. Maybe a client changed something, or material costs went up unexpectedly, or something was discovered during excavation that affected the project. The point is you want to learn why budget overruns happened and how the builder handled these situations.

Who will be the day-to-day contact?
Often there will be a project manager or site superintendent that will be your day to day contact on site throughout the project. You need to know who this person will be and make sure you can build a strong report with this individual. Their communication process will be key to the success of the project. They will also be in charge of managing all the various aspects of your project and the quality of their management skills is vitally important.

Bonus Tip:

Throughout the construction process, maintain open communication with your contractor and the design team. Schedule regular meetings - often called OAC (Owner, Architect, Contractor) meetings - to discuss progress, address any concerns promptly, and ensure the project aligns with your vision. And remember, it is always cheaper to make changes or work through problems on paper rather than in the field when things are getting built. Don’t cheap out by not engaging your design team to assist during the construction phase. They can save thousands of dollars and lots of time by helping answer questions, clarifying details, and troubleshooting the inevitable challenges along the way.

Next Steps for Your ADU

As discussed above, it is best to have a design in place as you begin your search to a builder to construct your ADU project. This is why starting with one of our pre-designed ADU plans can help you kickstart your project and save significant time. Take a look at our collection of modern ADU designs and find the layout that best suits your project goals and property.

Video: 5 Things to know before building your ADU

Southern Californians are racing to build accessory dwelling units — or ADUs — small, fully equipped homes on the same lot as a larger house. But building an ADU can be complicated and expensive. This video discusses 5 things you should know as you embark on building an ADU on your property.

Read the full story from the LA Times: You Do ADU, Part 1: Thousands of Californians are building ADUs. Should you?

7 Steps to Finding the Perfect Builder For Your ADU Project

Embarking on an Accessory Dwelling Unit (ADU) project is an exciting endeavor for homeowners like you, unlocking increased living space, rental income potential, and even multigenerational living possibilities. However, finding the right builder can make all the difference between a smooth process and a stressful one. With numerous builders available, each offering their unique expertise and approach, it's essential to navigate the selection process thoughtfully. In this guide, we'll walk you through the steps to help you find the perfect builder for your ADU project.

Step 1: Get Your ADU Design

Before venturing into builder searches, take time to solidify your ADU vision and develop the design for the project. The more design information you can provide the builders, the more accurate their cost estimate can be, and they can better discuss how they would execute the project. Including your ADU architect or ADU designer in the selection process can also be a great strategy, as they can help ask important questions and give you advice on the best fit for your project.

You can also start by selecting a pre-designed ADU design so you are beginning your contractor search with the knowledge that the ADU has been built before and you already can have a rough idea of costs before starting conversations with builders.

Step 2: Define Your Project Needs and Goals

Before diving into the search for a builder, take the time to define your project needs and goals. Consider factors such as the size of the ADU, your budget, desired timeline, and any specific features or design preferences you have in mind. Having a clear understanding of what you want to achieve with your ADU will help you communicate effectively with potential builders and ensure they can meet your expectations.

Step 3: Research Builders in Your Area

Once you've defined your project needs, start researching builders in your area who specialize in ADU construction. Look for builders with experience and a proven track record of delivering high-quality ADUs that align with your vision. You can start by asking for recommendations from your designer, friends, family, or colleagues who have recently completed ADU projects. Additionally, explore online resources such as builder directories, review websites, and social media platforms to gather a list of potential candidates.

Ideally, you should develop a list of 5-10 companies in your area that you are potentially interested in working with. This “long list” will be the businesses you will research in more depth before reaching out to them.

Step 4: Review Portfolios and References

After compiling a list of potential builders, take the time to review their portfolios and gather references from past clients. Look for builders who have experience working on projects similar to yours and have a portfolio that showcases their craftsmanship and attention to detail. If they have projects that align with your aesthetic taste, that is a bonus. Reach out to past clients to inquire about their experience working with the builder, including communication, project management, and overall satisfaction with the finished ADU. It is good to ask about how they dealt with any challenges or hurdles that come up in the process. No project is smooth from start to finish so knowing how people deal with conflict resolution is key to having a great working relationship.

Step 5: Schedule Initial Consultations

Once you've narrowed down your list of potential builders to 2-4 ideal companies, schedule initial consultations to discuss your project in more detail. Use this opportunity to ask questions about the builder's experience, approach to ADU construction, project timeline, and pricing structure. Pay attention to how the builder communicates and whether they listen to your needs and preferences. Building a strong rapport with your builder is essential for a successful collaboration, so trust your instincts during the consultation process.

We typically recommend interviewing the builders and ideally meeting on site if they are available and willing. Also, having a series of questions that you ask all the builders you interview can help you compare their responses to find the best fit.

Step 6: Request Detailed Proposals

After meeting with potential builders, request detailed proposals outlining the scope of work, project timeline, materials and finishes, and pricing. Review each proposal carefully and compare them side by side to ensure they align with your project needs and budget. Pay attention to any discrepancies or areas where clarity is needed, and don't hesitate to ask questions or request revisions as needed. A transparent and detailed proposal will help you make an informed decision when selecting a builder for your ADU project.

This is another place that your design team can be a huge help. Architects and designers can help compare bids, clarify areas that may be confusing, answer your questions, and look for opportunities to potentially save costs. It is highly recommended that you engage your designers to benefit from their expert advice during this process.

Step 7: Check Licensing, Insurance, and Credentials

Before making a final decision, take the time to verify that your chosen builder holds the necessary licensing, insurance, and credentials to perform ADU construction in your area. Check with your state or local licensing board to ensure the builder is properly licensed and in good standing. Additionally, verify that the builder carries adequate liability insurance and workers' compensation coverage to protect you and your property throughout the construction process. Finally, consider any additional certifications or affiliations that may indicate the builder's commitment to quality and professionalism.

Conclusion

Finding the perfect builder for your ADU project requires careful research, thoughtful consideration, and clear communication. By following these seven steps, you can ensure you find a builder who can bring your ADU vision to life. Remember to trust your instincts, ask for advice from your design team, ask lots of questions, and prioritize transparency and professionalism throughout the process. With the right builder by your side, your ADU project will be off to a successful start.

A Comprehensive Collection of ADU Links and Resources Across the US and Canada

Are you ready to embark on the journey of creating your very own Accessory Dwelling Unit (ADU) project? At Modern ADU Plans, we have curated an invaluable list of resources that outline a wide range of information and resources about ADU projects throughout the United States and Canada.

Whether you're a homeowner, builder, designer, or investor, the list below should lead you to some great information to make your project a success. And we will keep updating and adding to this list as we find more helpful information to share.

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Myth Busting the Owner-Builder Approach for ADU Projects

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When considering an Accessory Dwelling Unit (ADU) project, one of the critical decisions you'll face is whether to take the path of an owner-build or entrust the project to experienced professionals. While owner-building might seem like a cost-saving venture at first glance, this article aims to shed light on the fact that the often-illusory savings in dollars come at the substantial cost of time, stress, and potential pitfalls. As an advocate for well-executed ADU projects, I'll discuss the pros and cons of owner-building, ultimately making a compelling case for the investment in hiring experts to guide your ADU journey.

The Pros of Owner-Building an ADU:

  • Perceived Cost Savings: The primary allure of owner-building is the perception of cost savings. Some homeowners believe that by cutting out the professionals and managing the project themselves, they can reduce overall expenses. We have heard people say they saved 20% of the total construction cost, or even thrown out numbers like $100,000 in savings.

The Cons of Owner-Building:

  • Hidden Costs and Errors: Unfortunately, the reality of owner-building often diverges from the dream. Inexperience can lead to costly errors, mismanagement, and rework. Poorly executed projects can end up costing more in the long run when considering lifecycle costs. A slower scheduled impacts your ability to generate revenue if the ADU will be a rental unit. Missing regulatory requirements can cost a lot of money in redoing work or addressing potential future fines.

  • Time-Consuming: ADU projects are complex, requiring extensive time and effort for planning, permitting, subcontractor coordination, and construction. Owner-building often results in significant time commitments that can disrupt your daily life and add stress. If you have a full time job, your time is much better spent earning money with your expertise and hiring an experienced builder to lead your ADU project. Trust me, as I get older I understand that nothing is as valuable as my time and anything I can do to invest in time savings is worth it so I can spent more of my personal time with family and friends, doing the things I love.

  • Regulatory Challenges: Navigating local regulations, zoning codes, and building permits can be daunting without professional guidance. Mistakes in this area can lead to project delays and potential fines. They also could lead to legal issues in the future if you don’t meet code requirements. This can add a big risk to your investment.

  • Risk: When you build the project yourself you are liable for all mistakes and potential outcomes. If someone gets injured because something isn’t to code or a safety requirement isn’t met on the job site you can be sued. If you order materials and the wrong ones are delivered or they are defective, you can be on the hook for that sunk cost. You don’t have insurance or other financial protections like a general contractor does so you are taking on significant financial risk.

Why You Should Hire Experts:

  1. Expertise and Efficiency: Experienced ADU designers and general contractors bring a wealth of knowledge and expertise to ADU projects. They can streamline the process, ensuring that everything is done correctly and efficiently from the start, saving both time and money in the long run. Even though ADUs are small and seem simple, an experienced team is well worth the investment.

  2. Customization: Professionals work with you to create a design that suits your unique needs and preferences. They understand local regulations and can design an ADU that complies with zoning requirements while maximizing its potential. They can give you advise on ideal layouts, quality materials and systems, and actually save you money by considering things like sustainable features, lifecycle costs, and passive energy saving strategies.

  3. Quality Assurance: With experienced professionals, you can expect a high standard of workmanship, reducing the risk of costly mistakes and rework. This not only saves money but ensures a durable and aesthetically pleasing ADU. Contractors are liable for their work and carry insurance policies to protect them and you from costly mistakes and legal situations.

  4. Time Savings: ADU projects can be time-consuming and stressful, especially when managed by an inexperienced owner-builder. Professionals handle the details, timelines, and coordination, allowing you to focus on your daily life without undue disruption. They also have relationships with subcontractors, material suppliers, and others to get your ADU project completed in fewer months. This means you can start renting your ADU quicker and start generating income. Remember, every month of delay can cost you thousands of dollars in lost rent.

  5. Compliance and Permits: Experienced architects and contractors understand the regulatory landscape, ensuring your project is compliant with local codes and obtains the necessary permits. This eliminates the risk of project delays and costly legal issues.

Conclusion:

In the realm of ADU projects, owner-building might appear to be a cost-saving strategy. However, the hidden costs in terms of time, errors, and stress often outweigh any potential financial savings and often lead to projects that end up costing the same or more. Investing in the expertise of experienced designers and general contractors is the wise path for all ADU projects. Their knowledge, efficiency, and commitment to quality not only save you money in the long run but also ensure your ADU is a valuable and functional addition to your property. Don't let the allure of immediate savings cloud your judgment; opt for the experts, and your ADU project will thank you for it.

Your ADU is an investment and taking shortcuts or trying to save a dollar at the expense of quality is never recommended.

If you were considering doing an Owner-Build ADU project and have questions, don’t hesitate to reach out and tell us about your project.

ADU Design Guidelines: Sustainable Features

Adding an Additional Dwelling Unit (ADU) to your property can be a great way to increase rental income or extend the life of your home. But before you start construction, it's important to make sure that your ADU is designed in a way that is both sustainable and eco-friendly. In this blog post, we will discuss some of the most important features to consider when designing an ADU.

Orientation

The orientation of an ADU plays a vital role in maximizing sustainability. By carefully considering the placement of windows, doors, and the overall layout, homeowners can optimize the use of natural light and ventilation. Orienting the ADU to capture an abundance of sunlight can reduce the reliance on artificial lighting during the day, ultimately saving on energy consumption. Additionally, strategic positioning can promote passive cooling and heating, reducing the need for excessive air conditioning or heating systems. For instance, placing windows on opposite sides of the ADU allows for cross-ventilation, ensuring fresh air circulates throughout the space. By prioritizing sustainable orientation, ADUs can minimize their environmental impact while providing comfortable and energy-efficient living spaces.

Materials

In designing an ADU, incorporating sustainable materials is a paramount consideration for conscientious homeowners and designers. Utilizing sustainable materials not only promotes environmental preservation but also enhances the overall energy efficiency and durability of the ADU. From the foundation to the roof, sustainable materials can be implemented throughout the entire construction process. Choices such as FSC certified framing, reclaimed wood, bamboo flooring, and locally sourced products not only lend a unique aesthetic charm to the ADU but also significantly reduce the project's carbon footprint. Additionally, extra insulation coupled with active systems like solar panels and efficient heat pumps for heading and cooling can optimize energy efficiency, reducing the dependency on traditional energy sources - potentially even making your ADU net-zero energy. By employing sustainable materials, every aspect of an ADU's design can contribute to a greener and more sustainable future.

Active Systems

Active systems play a crucial role in contributing to the sustainable design of an Accessory Dwelling Unit (ADU). Incorporating renewable energy sources such as solar panels can provide clean electricity to power the electrical components of the ADU. Other systems to consider include installing a rainwater harvesting system which can collect and store rainwater for various purposes, reducing the dependency on municipal water sources. Furthermore, incorporating a geothermal heating and cooling system can utilize the stable temperature of the earth to efficiently regulate indoor climate, reducing the need for fossil fuel-based heating and cooling. These active systems not only decrease the environmental impact of the ADU but also contribute to long-term energy savings, making them an essential component of a sustainably designed ADU.

Passive design strategies for ADUs

Passive strategies are crucial for the sustainable design of an Accessory Dwelling Unit (ADU). By incorporating these strategies, homeowners can achieve energy efficiency and reduce environmental impact while ensuring a comfortable living space. For example, designing the ADU to maximize natural daylight, utilizing large windows and skylights, may reduce reliance on artificial lighting during the day, thus saving energy. Another strategy is proper insulation and air sealing, which prevents heat loss in the winter and heat gain in the summer. This reduces the need for excessive heating or cooling, resulting in significant energy savings. Additionally, passive solar design can be implemented by orienting the ADU to capture natural sunlight and heat, coupled with interior thermal mass from things like concrete floors you can reduce the need for artificial heating and lower overall energy consumption. By integrating such passive strategies, ADUs can contribute to a sustainable and energy-efficient living environment for homeowners. Plus, passive strategies often don’t cost any more to incorporate into your ADU project.

Simplicity and Less is More

Embracing simplicity and adopting a "less is more" approach can prove to be a prudent strategy for a sustainable ADU project. By prioritizing simplicity in design, construction, and functionality, we can reduce the environmental impact associated with materials, energy consumption, and waste generation. A minimalistic approach not only promotes efficient resource allocation but also encourages thoughtful use of space, enabling the creation of compact, smartly designed living areas that optimize functionality within a smaller footprint. By consciously scaling down, we reduce the demand for resources and energy, curbing both carbon emissions and operational costs. Moreover, a simpler design aesthetic can withstand the test of time, reducing the need for frequent renovation and minimizing the consumption of additional materials over the lifespan of the ADU. In essence, simplicity and a "less is more" mentality offer a sustainable pathway for an ADU project that focuses on responsible and efficient resource utilization in an environmentally conscious manner.

In conclusion, ADUs have emerged as a practical and sustainable solution to address the changing needs of homeowners and communities across the country. With their flexibility, affordability, and minimal impact on the environment, ADUs have transformed the way we think about housing. By providing an additional living space, ADUs not only offer a way to combat the housing crisis but also promote multigenerational living, create opportunities for rental income, and foster community cohesion. As cities adapt their policies and regulations to facilitate the construction of ADUs, it is clear that these innovative structures will continue to play a crucial role in shaping the future of housing, offering both homeowners and renters a versatile and efficient living option. The next step is making every ADU as sustainable as possible, to ensure that these housing types are great for our communities as well as the environment we call home.

Create your dream space today - purchase an ADU plan and unlock the potential of a versatile, stylish, and functional backyard home for your property.

To make this ADU as energy efficient as possible we wrapped the entire thing in rigid exterior insulation (3” on the roof, and 2” on all of the walls. The building envelope is so efficient that the heating system rarely turns on in the winter.

Understanding California's Title 24 Requirements for Accessory Dwelling Units

Accessory Dwelling Units, or ADUs, are becoming an increasingly popular way to add living space and housing options to existing residential properties. In California, ADUs are subject to a number of regulations and requirements, including Title 24 of the California Code of Regulations. Title 24 sets standards for energy efficiency, lighting, and other aspects of building design and construction. In this blog post, we will explore California's Title 24 requirements for ADUs and explain what homeowners and builders need to know to ensure compliance.

Promoting Energy Efficiency

One of the main purposes of Title 24 is to promote energy efficiency and reduce the environmental impact of buildings. California has set ambitious goals for reducing greenhouse gas emissions and promoting sustainable building practices, and Title 24 is a key tool in achieving these goals. The regulations apply to all new construction and remodeling projects in the state, including new construction ADUs.

Insulation, Systems, and Construction Considerations

For ADUs, Title 24 requires compliance with specific energy efficiency standards. This includes requirements for insulation, air sealing, heating and cooling systems, and more. For example, ADUs must have insulation that meets minimum R-value requirements, and they must be designed to minimize air leakage. HVAC systems must also meet certain efficiency standards to reduce energy consumption and emissions. We typically recommend that ADUs have insulated wall cavities in addition to continuous rigid insulation around the entire outside of the home. We also recommend ductless mini-split systems as an efficient way to provide heating and cooling.

Lighting Considerations

In addition to energy efficiency requirements, Title 24 also sets standards for lighting in ADUs. These requirements are designed to promote energy efficiency and ensure that ADUs are well-lit and safe for occupants. This includes requirements for the type and placement of light fixtures, as well as the use of lighting controls such as timers and motion sensors. To meet lighting requirements and reduce energy consumption we recommend LED light fixtures throughout all ADU projects.

Accessible Design

Another important aspect of Title 24 for ADUs is the requirement for accessible design. California law requires that all new construction and remodels meet accessibility standards under the Americans with Disabilities Act (ADA). This includes ADUs, which must be designed to be accessible for individuals with disabilities. This may include features such as wider doorways, lower countertops, and accessible bathroom facilities.

Solar Energy Requirements

An important aspect of Title 24 is the requirement to add solar energy systems that will offset the energy use of new construction residential projects. This includes ADUs. It is important to consider this requirement when budgeting for your project as well as locating the ADU on your property. Making sure the roof pitch is best oriented towards the sun will help you get the maximum benefits of a PV system. Along with solar energy production, you could also consider solar hot water systems and a way to further reduce your energy consumption and make your ADU more sustainable.

How To Comply

Most jurisdictions in California require a Title 24 report that analyzes your ADU design and does that calculations to show it complies with the code requirements. There are many companies that can provide these reports in only a few days time and typically for a few hundred dollars. They will provide the documentation and/or drawings needed to submit to your building department as part of the permit review process.


Overall, California's Title 24 requirements for ADUs are designed to promote energy efficiency, safety, and accessibility. While complying with these requirements can add some additional costs to a project, it is important to ensure that ADUs are built to the highest standards of quality and sustainability. By following these requirements, homeowners and builders can create ADUs that are comfortable, safe, and environmentally friendly, and that will provide long-lasting benefits for years to come.

Typically Title 24 reports are performed once the design of the ADU is completed but prior to submitting to permit. You can use our pre-designed ADU drawing sets to send to a company that provides Title 24 Reports and typically you can get the report in a few days.

Rooftop solar panels.
Photo by Mischa Frank

Seattle Is Permitting More ADUs Than Single Family Homes

According to a recent article in the Seattle Times, the growth in popularity of ADUs has seen the more ADUs permitted than single family houses. This is a welcome change in that it shows that changes to local regulations meant to encourage ADUs are working, but also that demand ADUs and multi-unit properties is outpacing the antiquated idea of single family houses in our cities.

We are definitely a fan of densifying our cities and ADUs are an important part of that. Density is beneficial for everyone as it leads to more amenities, new neighbors, more customers for local small businesses, and a larger tax base to fund public infrastructure like public transit, parks, and schools.

One of the things that drives what we do is providing more housing opportunities and more affordable homes. As this article points out, ADUs can help achieve these goals whether they are for rental or turned into a for-sale home by condoizing the property.

It is encouraging to see so many new homes being permitted, although this is still just a small drop in the bucket for the number of homes we need to be building to keep up with demand and growth projections. We would love to see ADU regulations be standardized state-wide or even nationally, rather than city by city. Having a patchwork of different rules and restrictions makes ADUs harder to design and build and often limits some types of ADUs, like modular or pre-designed ADUs.

We believe it would benefit everyone to make ADUs more accessible by taking down barriers to this housing type. It would make housing more affordable overall, it would make ADUs more attainable for more homeowners, it would allow for more multi-generational living or co-housing options, and will help meet our housing needs by working within the context of our many single family housing neighborhoods.

Another interesting aspect of this data is the balance between detached ADUs (DADU) - or backyard cottages - and attached ADUs - often called junior adus - which are often renovations to interior spaces like basements or attics. Detached ADUs are definitely leading the way but it was pretty close

It is also interesting to read that ADUs are becoming an amenity that developers are including in new homes. Rather than taking a property and building a single family house, developers see the interest in ADUs and are making projects that already have detached ADUs or attached adus included. And in places where it is allowed, sometimes both - meaning 3 units are being built instead of just one. This is really great to see.

Still, ADUs are a very small percentage of the overall housing production, with the most homes coming from new multi-family housing developments. Out of the approximately 11,000 homes built in the Seattle area, a little under 1,000 came from ADUs. Backyard Cottages, basement apartments, garage conversions, and other types of ADUs are still growing in popularity and will continue to be an important part of our future housing supply. Especially in neighborhoods that aren’t zoned for larger scale development, ADUs can easily become the easiest and most affordable way to add new homes.

Overall, this is great to see in the Seattle area and aligned with what we are seeing in many cities across the country. As more state legislatures adopt state-wide ADU regulations we are optimistic that ADUs will become an even larger piece of the housing pie.

Features of The Best ADU Designs

What makes one ADU design better than another? Lessons learned from designing over 60 custom ADUs and offering award winning pre-designed ADUs has lead us to some fundamentals in good ADU design. Designing the best ADU for your property requires careful planning, consideration of your needs, and the help of an experienced design team. Through years of experience we have crafted beautiful and functional ADUs that are some of the best available plans on the market. In this blog post, we'll explore what makes the best ADU design.

  1. Functionality and Flow

    The best ADU designs take into account the function and flow of the space. A well-designed ADU should feel spacious and open, with well-defined areas for living, sleeping, and cooking. The layout should flow smoothly from one area to another, and provide ample storage space. The design should also take into account the specific needs of the inhabitants, such as mobility and accessibility requirements. Since ADUs are smaller homes, it is imperative that their layouts are efficient and functional.

  2. Energy Efficiency

    Another important aspect of the best ADU design is energy efficiency. An ADU that is built with energy-efficient materials and features can save you money on your utility bills and reduce your environmental impact. Features such as continuous insulation, low-flow fixtures, and energy-efficient appliances can help you save on energy costs, while also making your space more comfortable and sustainable. Passive strategies like sun shading, natural light, thermal mass and other features are things that a great ADU design can incorporate.

  3. Integration with the Existing Property

    The best ADU design is one that seamlessly integrates with the existing property. A well-designed ADU should complement, but not necessarily mimic, the style and character of the main home, while also providing a unique and independent living space. It's important to consider the landscaping and outdoor areas when designing an ADU, so that the entire property looks cohesive and well-designed.

  4. Privacy and Comfort

    Privacy and comfort are also important aspects of the best ADU design. The design should take into account the privacy needs of the inhabitants, as well as provide a comfortable and relaxing living space. This can be achieved through the use of soundproofing materials, adequate lighting, and comfortable furnishings. This is important both in terms of the interior design of the ADU, providing privacy between spaces, as well as between the ADU and the main house.

  5. Flexibility and Adaptability

    Finally, the best ADU design should be flexible and adaptable to changing needs. An ADU that can be easily modified or repurposed as your needs change can save you money and hassle in the long run. The design should take into account the possibility of future modifications, such as adding or removing walls, or changing the use of the space - perhaps from a rental unit to a home office, or from a guest suite to a home for an aging parent. One of the true benefits of an ADU is that they can be used for so many things over the years.

In conclusion, the best ADU design is one that takes into account functionality, energy efficiency, integration with the existing property, privacy and comfort, and flexibility and adaptability. By working with an experienced design team, you can create an ADU that meets your specific needs and enhances the value of your property.

The design locates the large floor to ceiling windows overlooking the trees in the backyard, providing great views into nature but lots of privacy from the surrounding houses.

ADU Plans For Sale. A Great Way To Begin Your ADU Project

If you're looking to add extra space and value to your property, you may be interested in purchasing ADU plans that are for sale online. ADUs are quickly becoming popular among homeowners as a way to increase living space or generate passive income, and there are numerous benefits to building one on your property.

When searching for ADU plans for sale, it's important to understand the different types of ADUs available and which options may be best suited for your needs. The most popular types of ADUs include garage conversions, backyard cottages, and basement apartments.

Garage conversions are one of the most popular types of ADUs and involve converting an existing garage into a separate living space. Basement apartments are another popular option, which involves converting an existing basement into a livable space.

These can be affordable options for homeowners as it eliminates the cost of building a separate structure. However, they aren’t the best option for many. Not every property has a suitable garage or basement, many homeowners don’t want to lose the parking or storage space, and if the existing garage structure or basement isn’t in good condition or built to code, it could actually be more expensive to convert it into an ADU that building a new detached ADU. It is also difficult to purchase a pre-designed ADU plan for a garage or basement conversions. You will most likely have to spend more on the design fees to make a custom solution for the specifics of your garage structure or basement space.

Backyard cottages, or Detached ADUs, are standalone structures that are typically built in the backyard and can range from small studio apartments to larger two-bedroom homes. When searching for ADU plans for sale, it's important to consider factors such as size, layout, and design. Many homeowners opt for open floor plans, which create a sense of spaciousness and make the most of the available square footage. Others may prefer a more traditional layout, with separate rooms for living, dining, and sleeping. The design style of an ADU is also important, as it can impact its rental value and overall appeal.

Another important consideration when purchasing ADU plans for sale is local zoning and building regulations. It's essential to understand the requirements in your area and work with professionals such as designers, architects, engineers, and contractors to ensure that your ADU meets all necessary codes and regulations. Starting by purchasing ADU plans can save time while still working with a local expert to help with small revisions and the permitting process.

When it comes to purchasing ADU plans for sale, there are numerous resources available online. Many websites like Modern ADU Plans, offer a variety of plans to choose from, ranging from small, basic structures to larger, more complex designs. The cost of these plans can vary widely, with some plans available for a few hundred dollars and others costing several thousand dollars or more. There is also the option of starting with an ADU plan and the working with us to adapt or revise the design to meet your specific needs.

It's important to be selective when choosing a plan, and consider factors such as the size of your property, local zoning codes, your budget, and your desired outcome. You may also want to consider the potential resale value of your ADU, as this can impact your long-term investment. All of these factors can influence the appropriate project budget and the ultimate return on your investment.

We have seen ADUs grow in popularity across the country. We follow ADU rules and regulations as well as research what homeowners are searching for to find more information about ADUs. Some of the most popular keywords when searching for ADU plans for sale include "small house plans", "guest house plans", "modern house plans", "cottage plans", "backyard studio plans", and "granny flat plans". These keywords are indicative of the desire for homeowners to find a small, affordable, and modern living space on their property, and highlight the flexibility and versatility of ADUs. Although we think the plans we offer at Modern ADU Plans are beautifully designed and meet a range of project goals and desires, there are many options out there.

In summary, purchasing pre-designed ADU plans can be a smart investment for homeowners looking to add extra living space and value to their property. With a wide range of plans available online and the flexibility to choose the best option for your specific needs, there has never been a better time to explore the benefits of ADUs. By considering factors such as size, design, and local zoning regulations, and utilizing the most popular ADU search keywords, homeowners can find the perfect ADU plan for their property and start generating passive income.

While pre-designed ADU plans are great options for many homeowners, we also offer custom designed ADUs for those who want something unique, luxurious or high-performance. The cost for a custom designed ADU is definitely higher than purchasing ADU plans for sale, but for those looking to invest in something special please contact us to discuss your project.

Example of an ADU floor plan drawing

This is a sample page from one of our Modern ADU Plan sets. It shows the ADU’s floor plan, roof plan and a reflected ceiling plan.

ADUs As A Strategy For Passive Income

Our Personal ADU Investment Story

If you are considering adding an ADU project to your property as an investment and have any questions, don’t hesitate to reach out. I started this business to help people realize the dream of adding an ADU and starting to earn passive income through real estate investment. Althought I am trained as an architect and have designed dozens of custom ADU projects over the years, it is through building one for ourselves that really proved the power these small projects can have on improving your life and wealth.

My wife and I added an ADU to a property we owned in Portland, Oregon, converting an interior part of a house into a 1 bedroom rental unit. We rolled up our sleeves and did most of the work, from designing a compelling modern interior aesthetic, to lifting a sledge hammer to do the initial demolition work.

The original house was purchased for around $325,000 and we spent about $100,000 on the build to add the internal ADU. We did a lot of the construction work ourselves to save on labor costs - it would be been closer to $150,000 if we hired a GC to do the whole thing. We then rented the ADU for around $1,800 a month. We also rented the main house for around $2,400 per month and the rental income from the two units combined covered the full mortgage payments, maintenance costs, property management fees, and left a a few hundred dollars per month in our pocket.

After 4 years or renting out the property we moved across the country and ended up selling it for about $610,000. Overall, it was a great investment and adding the ADU was a huge part of that. We probably put in about $175,000 in cash including the down payment, property improvements, adding the ADU, and general maintenance and upkeep. Just with the sales price we earned close to a 100% return on that initial investment. Of course a hot market helped a lot, but making two cash generating rental units pushed up the sales price significantly.

ADUs Are A Great Passive Income Strategy

As the cost of living continues to rise across the country, it has become increasingly difficult for many people to afford their monthly bills and expenses or to purchase property of their own. In order to generate additional income, many people are turning to passive income strategies like investing in real estate. One real estate investment that has become increasingly popular in recent years is building accessory dwelling units (ADUs) on existing properties. This allows you to maximize the investment in your own property, and helps people afford to purchase a home by using rental income to help cover mortgage payments. In this blog post, we will explore the concept of ADUs as a strategy for generating passive income.

What Are ADUs?

ADUs, also known as accessory apartments, in-law units, or granny flats, are self-contained living spaces on the same property as a primary residence. These living spaces are typically smaller than the primary residence and can be used for a variety of purposes, such as rental units, guest houses, or additional living space for family members. ADUs can be attached to the primary residence, such as in the form of a basement apartment, or detached, such as a separate backyard cottage. In general, ADUs are great investments that can have a great ROI.

Why Build an ADU?

There are a number of reasons why building an ADU can be a smart investment strategy. One of the primary reasons is that an ADU can generate passive income in the form of rental income. Renting out an ADU can provide a steady stream of monthly income that can help cover mortgage payments, utility bills, and other expenses. Additionally, an ADU can increase the value of a property, making it an attractive investment option when considering the long term value of a property and future sales price.

Another advantage of building an ADU is that it can provide flexible living arrangements for homeowners. For example, if a homeowner has aging parents who require assistance with daily living, an ADU can provide them with a separate living space while still allowing them to be close to their family. Additionally, if a homeowner has adult children who want to live independently, an ADU can provide them with a more affordable living option. These benefits are financially positive as an ADU could be more affordable than the cost of assisted living or market rate housing in high demand cities, saving significant costs on a month-to-month basis.

How Much Income Can You Generate with an ADU?

The amount of income you can generate with an ADU will depend on a variety of factors, including the size and type of ADU, the location of the property, and the rental rates in the local market. In general, however, ADUs can be a lucrative source of passive income. According to a report from the National Association of Home Builders, the median rental income for an ADU in the United States is approximately $1,400 per month. In higher cost cities like Berkeley, Seattle, Los Angeles, or Vancouver, Canada, it is possible to rent out ADUs for over $3,000 per month. And where you can list them on AirBnB or other short-term rental sites, we have seen people earn well over $4,000 per month in revenue off a well designed ADU.

Of course, the amount of income you can generate will also depend on your rental strategy. If you choose to rent out your ADU on a long-term basis, you can expect to generate a consistent stream of monthly income. However, if you choose to rent out your ADU on a short-term basis, such as through a platform like Airbnb, you may be able to generate even more income per night, although the income stream may be less consistent from month to month.

Beyond the rental income, resale value is another aspect of investing in an ADU, although this technically is not passive income it is still important to consider at the outset of your ADU project. A 2021 study covered in Porch.com showed that homes in the western U.S. sold for about 35% higher than homes without an ADU. When combined with the rental income you can earn prior to selling a property, ADUs almost pay for themselves twice.

What Are the Costs of Building an ADU?

The cost of building an ADU will depend on a number of factors, including the size, type, and location of the unit, as well as the cost of materials and labor in your area. According to a report from the Urban Land Institute, the cost of building a detached ADU can range from $90,000 to $500,000, while the cost of building an attached ADU can range from $75,000 to $250,000. In our experience, when you combine the full cost of the project, including design, engineering, permits, utilities, site improvements, and construction, most ADU projects cost over $200,000 and could be much higher in expensive cities. Yet, this is still a strong investment.

While building an ADU can be a significant investment, it is important to keep in mind that it can also provide a significant return on investment in the form of rental income and increased property value. Additionally, there may be financing options available to help offset the initial costs of building an ADU, such as home equity loans or lines of credit.

Starting with a market analysis of the rental prices can help you work backwards to determine the maximum project budget. As a back of the envelope calculation you can spend about $100 on the development of an ADU for every $1 of monthly rent. For example, if you could rent your ADU for $3,000 per month in Berkeley, California, a comfortable project budget would be around $300,000.

This is just a general rule of thumb and not meant to replace a more in-depth financial analysis. There could be many reasons why you want to spend more than the rough estimate above. For instance if you wanted to add an amenity for the main house like a garage below the ADU, or you wanted to build a fancier unit with higher-end finishes knowing it would be more durable and have lower lifetime costs. Or perhaps you wanted to invest in super efficient systems or passive house construction to reduce energy usage, lowering the operational costs. Another reason to increase the up front investment would be to consider the resale value of the property in the future. Good design can often add 10% or more to the sales price of a property. Often going with the cheapest solution is not the best investment.

Questions to Ask Yourself When Considering an ADU as an Investment

  • What are the long-term goals for the project?

  • What is the local market for rental units? What is the average monthly rent for similar sized units in your location?

  • How many bedrooms are ideal to maximize the rental price?
    (Typically we would see 2br units as the best option for investment ADUs)

  • What do I need as a monthly ROI to make this project worth it?
    (You want it to be cashflow positive after any financing you take out to fund the project)

  • What financing options are available and how much will I need to borrow?

  • What is the maximum project budget for the ADU?
    (include all potential costs like design fees, engineering, surveys, permits, and construction, etc.)

  • Who will manage the rental unit when it is complete?
    (There really is no such thing as truly passive income. Rental properties take time and effort to manage. Are you ready to take on this work on your own or do you want to hire a rental management company to handle it for you?)

In conclusion, ADUs can be an excellent investment for those looking for a passive income stream. They offer homeowners an opportunity to create additional space on their property while generating rental income.

To maximize the return on investment, homeowners should consider factors such as location, design, and potential rental income when deciding on an ADU project and crafting the project budget. It’s also important to be aware of local zoning and building regulations and work with experienced professionals such as designers, architects, contractors, and property managers to ensure a successful outcome.

While the initial investment may be high, the long-term benefits of owning an ADU are clear. Not only can they generate passive income, but they also increase the value of a property and can provide a multi-generational housing solution for families.

As the demand for affordable housing options continues to rise, ADUs will continue to be an attractive investment for homeowners looking to generate passive income while also contributing to their local communities. By taking advantage of the benefits of ADUs, homeowners can build a secure financial future for themselves and their families.

This is a basement ADU design we worked on for a family in Portland, Oregon. They live in the main house above and rent this unit out on Airbnb and use it for friends and family. They make a nice income off the short term rental and it helps them cover the cost of their mortgage.

Backdoor Revolution: The Definitive Guide To ADU Development by Kol Peterson

When I was living and designing ADUs in Portland, Oregon, I became friends with Kol Peterson, bonding over our shared interest in ADUs and our work to help homeowners add these projects to their properties. Kol was an incredible teacher, promoter, and advocate for ADUs and other small homes. Through his experience building his own ADU, offering courses and consulting with homeowners across the country, and organizing events such as the Build Small Live Large conference, he evolved into one of the country’s leading experts on ADU projects.

Backdoor Revolution: The Definitive Guide To ADU Development, captures Kol’s immense knowledge and passion for ADUs and packages it into a book that helps make ADUs more attainable for every homeowner. If you are interested in ADUs or want to add one to your property, this is a great resource that can help get you started on the right path.

Garage Conversion vs. New Construction: Choosing the Best ADU Option

Are you considering converting your garage into an accessory dwelling unit (ADU)? It's a popular choice among homeowners who want to create more living space on their property and already have a garage structure in place. However, while converting a garage into an ADU can be a tempting option, it may not always be the best choice. In this blog post, we'll explore the pros and cons of garage conversion versus new construction for an ADU.

First, let's define what an ADU is. An ADU is a self-contained living unit that is added to a property's existing structures. ADUs are becoming increasingly popular in many cities as a way to address the housing shortage and provide additional living space for homeowners or rental income.

When it comes to converting a garage into an ADU, there are several advantages. The existing structure of the garage means that the foundation and framing are already in place, which potentially can save time and money compared to building from scratch. In addition, many garages already have utilities such as electricity and plumbing connected, which can also save on costs. We say potentially because starting with an older garage where the foundation, framing, siding, or roof are in poor shape could actually cost more to repair than building a completely new ADU from the ground up.

However, there are also several disadvantages to converting a garage into an ADU. For example, most garages are not designed with the same level of insulation as a living space, which can result in higher heating and cooling costs. Garages may also not have enough natural light, which can make the space feel dark and cramped. You could add windows and doors to bring in more light of course, but often older garages are built on property lines that may limit the ability and location where windows can be added. Additionally, converting a garage may not always be possible due to zoning regulations or structural limitations.

Another drawback is that often garages don’t have the utility hookups that will be required. Water, sewer, and electrical connections could require you to cut up existing foundations or slab within the garage in order to get the utilities to the right places. This isn’t a deal breaker, but is a costly part of the conversion process.

On the other hand, building a new ADU from scratch can offer several advantages. For one, a new ADU can be designed specifically for living, with features such as proper insulation, natural lighting, and more spacious layout. A new construction ADU can also be designed to match your aesthetic taste, or the style of the existing home and be tailored to the needs of the homeowner or potential renters. Additionally, new construction ADUs are often larger than converted garages, providing more living space and potentially increasing rental income and property value.

While building a new ADU may seem like a more expensive option at first, it's important to consider the long-term benefits. A new construction ADU is likely to have a longer lifespan than a converted garage, which may require more maintenance and repairs over time. And when you consider energy efficient design and construction the new ADU will probably be much cheaper to operate on a monthly basis with lower utility bills. A new ADU can also potentially increase the value of your property more than a converted garage, which can be especially important if you plan to sell in the future.

In conclusion, while converting a garage into an ADU may seem like an attractive option, it's important to carefully consider the pros and cons before making a decision. In many cases, building a new ADU from scratch may offer more long-term benefits and be a better investment for homeowners. Ultimately, it's important to work with a trusted advisors, designers, and builders to explore all of your options and make an informed decision based on your unique situation and goals.

We are happy to answer questions and help advise you on the right path to adding an ADU based on the specifics of your property and your personal project goals. Please reach out to tell us about your ideas and we will do our best to help in any way we can.

How Long Does It Take To Build An ADU?

After cost, timeline is one of the most commonly asked questions by those looking to add an ADU to their property. It is important to understand the full project timeline and not just the construction phase as you begin to plan your project.

Projects can typically be broken down into 4 phases:

  1. Planning and Research

  2. Design

  3. Permitting and Approvals

  4. Construction

The Planning and Research Phase: 4-8 weeks but potentially longer

This is vital to having a successful project as it is always easier and cheaper to make decisions on paper than when the project is under construction. It is also important to have the base research done to understand and accommodate the wide range of factors that will impact the project, from local rules and regulations, material supply availability, cost of materials and labor, interest rates and other financing information, to the specifics of the existing conditions of the property.

The length of time for this phase can vary from a few weeks to a few years depending on the client and how motivated they are to move forward with the project. When clients come to us to assist with this work, we typically estimate about 4 weeks to review the property, understand the local rules and regulations, and work with the client to develop a project budget and building program.

The ADU Design Phase: 3-6 months but sometimes up to a year

A common theme in all of these rough timeframe estimates will be that it depends on the client. Some people are quick to make decisions or just trust the design team to make decisions for them. Others want to be involved with the specifics of each decision throughout the project or may need a good amount of time to think through the options before settling on what they want to do.

We typically walk clients through a custom designed ADU process in 3-4 months. We feel that is a good balance of collaborating on the important decisions while our expert designers handle the details as we develop the permitting and construction drawings. You can then add on another month or two for the various other consultants that may need to be involved in the project. This would be consultants such as structural, mechanical, electrical, and plumbing engineers, landscape architects, arborists, civil engineers and other professionals. Most of these consultants will need the architectural design to be complete before they can carry out their work.

This is a place that starting with a pre-designed ADU plan can save significant time. If you are ok with one of the designs that are available for purchase, you can condense 3-4 months into just a couple of weeks. You would basically be skipping most of the design work and moving straight into engaging with consultants.

The Permitting and Approvals Phase: 1 month to 1 year, or more!

That range may seem crazy and we agree. This is one of the biggest frustrations homeowners, designers, and builders of ADUs have in the process. Each jurisdiction has their own rules and regulations and often there are conflicting rules between towns/cities, counties, and states. It is challenging to work through the various levels of regulation. Adding further frustration is how slow most building departments are at responding to questions as well as reviewing and approving submitted plan sets.

For some specific examples, we found that it took about 4-6 months on average to work through the permitting process in Portland, Oregon. Places in the Bay Area, like San Francisco, Berkeley, Oakland and others, the process could easily stretch out to one year or more. Seattle also has incredibly long review processes, probably falling somewhere between Portland and the Bay Area. Smaller towns or states with less regulation often work a lot faster. Places like Idaho or Texas can review and approve ADUs in just a few weeks or months, assuming the town you are building in allows ADUs, and the designs meet the local codes.

We highly recommend talking with your local building department as part of your Planning and Research phase, to get a realistic estimate of the permitting time you can expect.

The Construction Phase: 6-9 months

Once you receive approved plans from the permitting process you can break ground and start construction. From this point you could probably assume a 6-9 month construction timeframe. Of course this could vary based on your local climate, material supply, labor market, etc. Also, some contractors have larger crews and may move quicker. You may also chose to work with someone who will take their time and be a bit more meticulous with the construction details to deliver a higher quality final result. Sometimes taking longer is prefered.

Remember a few key things: starting construction in the spring is ideal as you will hopefully avoid delays due to winter climate conditions (freezing cold, snow and ice, and heavy rains can delay construction significantly). In the post covid world, material supply chain and skilled labor are significant challenges to overcome. There are significant delays in getting some key building materials, especially windows, that could significantly extend the construction timeframe.

The construction timeline for building an ADU can also vary based on the type of ADU. Converting a basement or attic, or even a garage could potentially be a bit quicker to complete vs doing a ground up construction. Working within an existing structure - assuming it is weather protected - may not face climate caused delays and also may reduce some of the work such as pouring foundations or doing significant framing.

Overall ADU Timeline

If you are just beginning to consider adding an ADU a good safe estimate is it would take about 12-18 months from start to finish. That would include pre-design research, the architectural design phase, permitting approvals, and construction. Of course some jurisdictions - I’m look at you Bay Area - will probably throw some wrenches in the gears and take too long to review your project and issue permits, so it could take longer.

To bring this timeframe down you can consider strategies like starting with a pre-designed ADU, or even an prefabricated or modular ADU. It is also wise to plan for a a springtime construction start, and to hire your design team and general contractor well in advance so they can collaborate and plan for a successful construction process. The best time to start design would be late summer or early fall with the goal of starting construction the following spring or summer.

If you are starting a project and have any questions don’t hesitate to reach out. We are always happy to help you get on the right track. And if you want to cut down on your timeline and want to start with a pre-designed ADU plan check out our available designs by clicking the button below.