How to Find the Right ADU Builder in San Diego for Your ADU Project

Jun 9, 2024 | 1 comment

Choosing the right accessory dwelling unit (ADU) builder is essential for a successful project. An ADU builder specializes in navigating the complexities of designing, permitting, and constructing accessory dwelling units. Hiring a professional ADU builder ensures that your project adheres to all regulations, stays within budget, and meets high-quality standards. This can prevent many common issues and challenges that arise during the construction process.

We often hear from homeowners who are hesitant about starting their ADU project because they don’t know what to expect from working with a contractor. Some have had negative experiences in the past and are worried about encountering similar problems. Others are unsure if they need a general contractor, or if they can get by with a handyman, or even tackle the project themselves.

Here are some common concerns and questions San Diego homeowners have when choosing an ADU builder:

  • Past Negative Experiences: Homeowners who have previously worked with unreliable contractors are often worried about repeating those experiences. “How do I find a good ADU contractor?”
  • Cost and Budget: Understanding the costs involved and ensuring that there are no hidden expenses. “What does it cost?”
  • Project Management: Concerns about how the project will be managed, including timelines, communication, and handling unexpected issues. “How do I make sure I have a good experience building an ADU?”
  • Quality of Workmanship: Ensuring that the builder will deliver high-quality work that meets all safety and building codes. “How do I know it will turn out as I expect and stand the test of time?”

By addressing these concerns and questions, homeowners can feel more confident in their choice of an ADU builder and look forward to a successful and smooth project.

Why Choosing the Right ADU Builder Matters

Selecting the right builder is crucial for the success of your ADU project. An experienced and reliable ADU builder ensures that your project runs smoothly, stays within budget, and meets all regulatory requirements. Conversely, hiring an unreliable and less experienced builder can lead to a range of problems that could jeopardize your investment.

Potential Challenges and Risks with an Inexperienced Builder

Regulatory Compliance

ADU projects must comply with various local and state regulations and building codes. An experienced builder is familiar with these overlapping regulations and can navigate the complex permitting process. An inexperienced builder might overlook critical compliance issues, leading to costly delays and unexpected cost overruns due to unforeseen requirements (that could have been predicted).

Quality of Workmanship

The quality of construction directly impacts the longevity and safety of your ADU. Unreliable builders may cut corners, use subpar materials, or lack the skills to execute the project to high standards. This can result in structural issues, poor insulation, visible damage years or even months after the build is complete, and other defects that diminish the value and functionality of your ADU.

Project Delays

Timely completion is essential for any construction project. Inexperienced builders might underestimate the time required, mismanage resources, or face frequent setbacks. These delays can increase costs and disrupt your plans.

Cost Overruns

Budget management is a critical aspect of any construction project. Reliable builders provide accurate estimates and maintain transparency throughout the project. In contrast, unreliable builders might provide low initial bids to win the contract but later introduce numerous unexpected costs, leading to significant budget overruns.

Real Examples of Issues to Avoid on ADU Projects

We have an entire article devoted to documenting the many hurdles that can arise in an ADU project, and what an experienced design build company like us was able to do to overcome them. Choosing the right ADU builder is crucial to avoid pitfalls and ensure a successful project. A reputable and experienced builder will provide accurate estimates, high-quality workmanship, and navigate regulatory requirements efficiently, ultimately saving you time, money, and stress.

What Should I Look for in an ADU Contractor?

Finding a good contractor is half the battle when beginning your ADU project, as it seems there are endless options to choose from. When you decide to begin your search, be sure to keep these things in mind:

Specialization and Expertise

Does the contractor specialize in ADU projects and do they have experience with the type of ADU you want? The world of contracting is diverse, from large-scale builders to small remodeling services. Adding to this variety, ADUs come in different flavors: new builds, conversions, and additions. It’s important to find a contractor that’s just the right fit for your project, both in expertise and scale.

Constructing an ADU involves various intricate regulations & processes. So it can be extremely helpful to engage a contractor who has extensive knowledge in this specific field. Their familiarity with potential challenges that may arise during the ADU process can contribute to efficient time management and cost savings.

Similarly, they should have the right resources to handle a project of your size. Too small a contractor might struggle with larger projects, affecting timelines and costs. An ideal contractor will strategically plan your project from obtaining permits to actual construction, minimizing downtime and ensuring your ADU build stays on schedule.

Portfolio and Track Record

Are they proud to showcase their portfolio and track record? Do they have positive testimonials and reviews from previous clients? Your potential contractor’s portfolio is a gold mine of information. This gallery of past ADU projects will provide insights into the aesthetics and quality of the company’s work, demonstrating their execution competence from concept to build-out.

Given the privacy and liability concerns tied to ADUs (since they are situated on occupied properties), a majority of reputable builders might not offer onsite visits. In such cases, they make up for it with detailed portfolios and virtual tours. Look for a contractor who is proud to showcase their accomplishments, as this is indicative of their confidence in their work and their commitment to transparency.

Local Experience

Does the contractor operate extensively in your jurisdiction? Are they familiar with local building codes, zoning laws, and permit requirements? Every city has unique regulations that will affect your build, and your contractor should be able to provide insight as to what those are. Many companies will have informational resources available on the internet to help homeowners gain a better understanding of what a build might look like. However, when it comes to beginning a project, your contractor should be highly familiar with the intricacies of your jurisdiction’s ADU regulations.

Be aware of all the major requirements from the city and/or hire a company that will be accounting for these factors (e.g. will you need to upsize water meter, will you need a building location survey, has the ADU been designed to swiftly pass permitting etc).

Transparent Pricing

Is the pricing straightforward with no hidden fees? Do they provide clear and detailed quotes? Hidden costs can take the joy out of your ADU project. Avoid contractors who don’t provide clear pricing during the initial consultation or on their website, as this could hint at an unexpected change in costs. This can be a sales tactic to keep prices lower. Or this could be a genuine oversight because they simply don’t know the full scope of what will be required to permit and build the ADU. Consider a builder that is honest with you about the full pricing up front. Additional sitework costs will eventually come up whether or not your contractor anticipates them. Find a contractor who informs you of the true project cost upfront so you can plan accordingly.

Project Timeline

Do they provide a comprehensive and understandable timeline for your project? Are they realistic about the time it will take to complete your ADU? A good contractor will know what to expect for the timeline to build an ADU of the size you want, in your jurisdiction, and on your particular property. An ADU will take at least 10 months to design, permit, and build, and often much longer. A good builder won’t lure you with unrealistic estimates, but instead, will keep you informed about the project’s phases and their respective durations.


Is communication with them easy and responsive? How do they handle project management and updates throughout the build? A responsive contractor is a gem. If you find communication challenging even before signing a contract, consider this a red flag. Communication rarely gets better after the sales process, the time when a company puts their best foot forward. Also ask how the company handles their project management throughout the build, as well as their communications with you. If you can track your $12 Domino’s pizza in real time, you should be able to track your $400K ADU project live, too.

Payment Schedule

Do they have a reasonable payment schedule and policy that aligns with project milestones? Are they asking for large upfront payments? A reputable contractor will have a clear and reasonable payment schedule that aligns with project milestones. It’s generally unusual and could potentially raise concerns if a contractor asks for a large payment upfront. While a modest deposit may sometimes be necessary for the procurement of materials, typically you should not be asked to provide more than 15% upfront before the work commences. It’s crucial to establish these payment milestones upfront, so both parties understand the phases at which payments will be made. This ensures the financial aspect of the project runs as smoothly as the construction itself.

Warranty Policy

Do they offer a solid warranty policy that covers both cosmetic and structural issues after the project is completed? You want your ADU completed on time and on budget, but you also want to know the contractor will stand behind their work even after they’re finished. Sometimes issues can pop up after the job’s done, so how your contractor handles those can really matter. For instance, a reputable contractor typically provides a 2-year warranty covering any cosmetic defects that aren’t a result of standard wear and tear or the homeowner’s neglect. Additionally, they may offer a 10-year warranty against any structural flaws resulting from failure to comply with approved plans and specifications. This kind of policy safeguards your investment and peace of mind.

Licenses and Insurance

Do they carry the necessary licenses and insurance? Can they provide proof of general liability insurance and workers’ compensation? This is a given. In cases where thousands of dollars are going to be spent on a new guest house, your builder must have the correct certifications and training to carry out your job safely. Many companies will display their general contracting license number on their website or business profile, where they can be checked to ensure validity. They should also carry general liability insurance and workers compensation, as well as provide lien waivers.


Are they respected by local entities and individuals? Do they have good reviews and endorsements from the community and industry organizations? Good reviews can speak volumes about a contractor. Contractors endorsed by locals and organizations alike show that they are recognized experts, which can give you peace of mind about your investment in your new ADU. Also consider the quality and color of the reviews. How the contractor overcomes difficulties is extremely important, as construction is often dealing with the unexpected.

Red Flags to Watch Out for in an ADU Builder

Choosing the right ADU builder is critical to the success of your project. However, not all builders are created equal. Here are some red flags to watch out for when selecting an ADU builder.

Lack of Specialization

“We Do It All” Approach: Be cautious of builders who claim they can do everything. Building ADUs requires specialized knowledge and experience. Look for builders who have completed dozens of ADUs and have a deep understanding of the unique challenges involved.

Limited Knowledge of Local Regulations

Lack of Expertise in Local Codes: ADUs must comply with specific local regulations. Builders who are not well-versed in local building codes and permitting processes can cause delays and incur additional costs. Look up your local ADU regulations.

Unclear Pricing and Unforeseen Details

Lacking Detail in Bids: Beware of builders who provide vague or overly simplistic bids. Detailed and specific estimates are crucial for avoiding unexpected costs and ensuring transparency. Brush up on what to expect for your ADU costs so you know what to look for in bids and can hold your providers accountable.

Unrealistic Timelines

Overly Optimistic Estimates: If a builder tells you the project will be a breeze and can be completed in an unrealistically short timeframe, they likely don’t understand the complexities involved. A well-informed builder will provide realistic and achievable timelines. Read more about how long it takes to build an ADU.

Ambiguous Process

Uncoordinated Workflows and Partnerships: Some builders claim to partner with architects and other professionals but lack proper coordination. This can lead to miscommunication and inconsistent service. Opt for builders with clear processes and in-house resources to ensure a seamless project experience. Learn more about our project management.

One-Man Band

Limited Resources: While it’s nice to know who you are dealing with, a small operation often lacks the resources to manage large projects like an ADU effectively. This can result in delays, subpar workmanship, and a lack of experience in overcoming hurdles. Choose a builder with a large, in-house team to ensure comprehensive support and expertise. See the SnapADU team.

No Warranty or Poor Warranty Terms

Lack of Warranty: A reputable builder should offer a clear and comprehensive warranty for their work. If the warranty terms are vague or not easily accessible, it’s a sign that the builder may not stand behind their work. See more about our warranty.

Unwillingness to Share Portfolio

Limited Portfolio or Few References: A reputable ADU builder should be proud to showcase their work. If a builder is hesitant to share their portfolio or provide verifiable client testimonials, it’s a major red flag. See our ADU projects.

Negative Reviews and Poor Reputation

Lack of Online Reviews: A builder with no online presence or negative reviews should be approached with caution. Look for builders with positive feedback and a strong reputation in the community. Hear interviews with SnapADU clients.

By being aware of these red flags, homeowners can make more informed decisions and choose an ADU builder who is reliable, experienced, and committed to delivering high-quality results.

Tips for Choosing a Reliable ADU Builder in San Diego

Selecting the right ADU builder is critical to ensuring a successful project. Here are some expert tips to help you make an informed decision:

Conduct Thorough Research

Start by researching potential builders online. Look for reviews, testimonials, and portfolios to get a sense of their experience and quality of work. A builder with a solid online presence and positive feedback is often a good sign that their overall operations are running smoothly. Look for client testimonials and online reviews on websites like Google, Yelp, Houzz, and Better Business Bureau.

Schedule Multiple Consultations & Compare Bids

Meet with several builders to discuss your project. This will give you a better understanding of their approach, communication style, and professionalism. It also allows you to compare different perspectives and quotes. You’ve likely heard it’s wise to secure 2-3 bids on a project. If one bid is much lower than the rest, double check that there are no key components missing from the bid (plan submission & permit processing? sitework and utilities? any required solar? has each handled finish materials consistently?). A good contractor should want to minimize surprises so that clients are happy with the experience and want to refer others.

Read more about how to compare ADU quotes.

Evaluate Process, Communication and Transparency

Inquire about the ADU company’s project management process. A reliable builder should have a clear and organized process, be able to explain each step, and use project management tools like Buildertrend to keep you – and their subcontractors and team – informed. They should also be able to clearly articulate a detailed scope of work for your project, including the nuances for your specific lot.

Verify Builders’ Credentials

Ensure the builder is licensed, insured, and bonded. Check their credentials with local licensing boards and verify their insurance coverage to protect yourself from potential liabilities. Additionally, confirm their experience specifically with ADU projects, as this specialization can significantly impact the smoothness and success of your project. Check a License – CSLB.

By following these tips, you can find a trustworthy and experienced ADU builder who will help bring your vision to life while ensuring a smooth and efficient construction process.

Home Builder Digest has put together a list of The 11 Best Accessory Dwelling Unit Builders in San Diego, California.


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  1. Certifications and training are crucial because they ensure that the builder has the necessary knowledge and skills to handle the job safely and efficiently. It’s always a good practice to check the builder’s general contracting license number to verify its authenticity. This can be easily done by visiting their website or business profile, as mentioned in the article.

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