251 Oriole Ct, Hercules, CA 94547, USA
+1 (510) 224-5643

ADU Solutions

ADU Builder Contra Costa County CA

Building high-quality and affordable ADUs in Contra Costa since 2020.

Licensed & Insured ADU contractor in Contra Costa County CA

Satisfaction guaranteed
No hidden fees

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Your Local ADU Builder in Contra Costa

Building an ADU is a major project, and local experience matters. JL Home Service has 5+ years of experience building ADUs and remodeling homes in Contra Costa County, giving us a strong understanding of local homes, project requirements, and the challenges that can come with ADU construction.

From detached backyard units to garage conversions and additions, we help homeowners plan and build ADUs that fit their property, budget, and needs. We handle the project from the early planning stages through construction, coordinating the work needed to turn your ADU plans into a finished living space.

Because we work throughout Contra Costa County, we understand that every property is different. Lot size, existing structures, access, utilities, zoning requirements, and the design of your home can all affect how an ADU project should be approached. Our goal is to help you make informed decisions and build an ADU that adds useful living space and long-term value to your property.

What We Do

Types of ADUs We Build

Detached ADU

A detached ADU is a standalone structure built separately from the main house, typically in the backyard. Because it has its own entrance and complete separation from the primary residence, it offers the highest level of privacy.

This is often the preferred option for homeowners who plan to rent out the unit or create independent living space for family members. A detached ADU can feel like a completely separate home while still being located on the same property.

Attached ADU

An attached ADU is connected to the existing home while maintaining its own entrance, kitchen, bathroom, and living space. It functions as an independent dwelling without requiring a completely separate structure.

The biggest advantage is that it often costs less to build than a detached ADU since it can share portions of the existing home’s structure and utilities. It’s an excellent choice for homeowners who want additional living space while maximizing their available budget.

Junior ADU (JADU)

A Junior ADU is a smaller unit created within the existing footprint of a home, often by converting a spare bedroom, unused section of the house, or other underutilized space. JADUs are typically limited in size and are designed to make efficient use of space.

For homeowners looking for a lower-cost way to add living space, a JADU can be an attractive option. It allows you to create housing for a family member or generate additional income without a major construction project.

Garage Conversion ADU

A garage conversion transforms an existing garage into a fully functional living space. Instead of building a new structure from the ground up, the existing framework is repurposed into an ADU.

Many homeowners choose this option because it makes use of space they already have. If your garage is primarily being used for storage, converting it into an ADU can provide significantly more value while often reducing construction costs and timelines.

Basement ADU

A basement ADU converts an existing basement into a separate living unit with its own amenities and private living space. This type of ADU takes advantage of square footage that’s already part of the home.

The primary benefit is that you’re expanding usable living space without changing the home’s footprint. For properties with suitable basements, this can be one of the most efficient ways to add housing while preserving outdoor space.

Bump-Out ADU

A bump-out ADU is created by extending a portion of the existing home to add the space needed for an independent living area. Rather than building a completely separate structure, the home is strategically expanded to accommodate the ADU.

This option works well for homeowners who don’t have enough yard space for a detached unit but still want the benefits of an ADU. A bump-out can provide the additional room needed while maintaining the overall character and layout of the property.

ADU Building Process

Building an ADU may seem overwhelming at first, but our team guides you through every step. From the initial design to final inspections, we handle the details so you can focus on the excitement of adding valuable new space to your property.

01

Design

This is where your vision starts to take shape. We’ll discuss your goals, evaluate your property, and create a custom ADU design that fits your needs, budget, and local building requirements. During this phase, we’ll refine the layout, appearance, and functionality of the space before preparing the plans for approval.
Estimated Timeline: 4-6 weeks
Key Milestone:

02

Permits

Once the design is complete, we’ll prepare and submit the necessary plans and documents to the local building department. Our team handles the permitting process and coordinates with the city to address any plan review comments that may arise.
Estimated Timeline: 1-4 months
Key Milestone:

03

Build

After permits are issued, construction begins. This phase includes everything from site preparation and structural work to utility installation and interior finishes. Throughout the build, we’ll coordinate inspections and keep the project moving toward completion.
Estimated Timeline: 4-8 months
Key Milestone:

04

Live

Once construction is complete and all final approvals have been received, your ADU is ready to use. Whether it’s for family, guests, a home office, or rental income, you can start enjoying the benefits of your new space right away.
Estimated Timeline: Move-in ready
Key Milestone:

Expanding Contra Costa Homes with Custom ADUs

We help homeowners throughout Contra Costa design and build high-quality ADUs that add space, flexibility, and long-term value to their properties.

Our values

A Higher Standard of ADU Building in Contra Costa

We don’t just build ADUs — we build them right, with care in every step and results you can rely on.

Licensed and insured

We are fully licensed and insured, which means your ADU project is handled by a qualified team that follows all state and local building rules. This gives you peace of mind throughout the entire project, from planning and permits to construction and final inspection. You can feel confident that your home and investment are in safe hands.

Local expertise

We work in this area and understand the local building codes, zoning rules, and permit process that are required for ADU projects. This helps us plan everything correctly from the start, avoid common mistakes, and reduce delays during inspections. Our local experience helps keep your project moving in a smooth and organized way.

Clear pricing

We provide clear and detailed pricing before any work begins, so you know exactly what is included in your ADU project. We take time to explain the costs in simple terms, go over your options, and make sure you understand where your money is going. This helps you plan your budget with confidence and avoid surprise costs during construction.

Reliable timelines

We set a clear and realistic timeline for your ADU project and do our best to follow it closely. You will know what stage we are working on, what comes next, and when each part of the project is expected to be completed. If anything changes, we communicate with you right away so you are always kept informed.

Built to last

We build ADUs using strong materials and careful workmanship so your space will hold up well for many years. From the foundation to the final finishes, we focus on doing things the right way, not the fastest way. The goal is to give you a solid, comfortable space that stays reliable through everyday use and changing weather over time.
+1 (510) 224-5643
jaydenliamhomeservice@gmail.com
No hidden fees

FAQs

Frequently Asked Questions

How much does it cost to build an ADU Contra Costa?

The cost to build an ADU in Contra Costa County typically ranges from $150,000 to more than $450,000, depending on the size, design, site conditions, and level of finishes. For new construction, a general starting range is $250 to $400 per square foot, although more complex projects can cost more.

How long does it take to build an ADU in Contra Costa?

Building an ADU in Contra Costa County typically takes 7 to 14 months from initial planning to completion. This includes about 2 to 5 months for design and engineering, 2 to 4 months for permits and approvals, and 4 to 8 months for construction. The actual timeline can vary based on the ADU’s size and design, site conditions, permit requirements, and the complexity of the construction.

Do I need a permit to build an ADU in Contra Costa?

Yes, building an ADU in Contra Costa County requires planning approval and building permits. Your project must meet local zoning and planning requirements before you can move forward with the required building permits. Depending on the project, you may also need separate permits for electrical, plumbing, mechanical, and structural work.

Do you handle ADU permits and city approvals?

Yes. We manage permitting, zoning checks, and city paperwork. Each city has its own rules, and we work through them step by step. This helps avoid delays and keeps your project on track from early planning to approval.

Can I use an ADU for rental income?

Yes, many homeowners build ADUs to create rental income or house family. We can help you plan a layout that works well for long-term use. Local rules apply, so we guide you through what is allowed in your area.

Will an ADU increase my property value?

Yes, building a legally permitted ADU typically increases property value, often boosting a home’s market value by 20% to 35% or more depending on your local real estate market, the type of ADU built, and potential rental income.

Start Your ADU Project Today

Contact our team today to schedule a consultation and get started on a custom ADU designed for your property.