E&E Construction and Remodeling

Lic # 1107705


Accessory Dwelling Units (ADUs) are becoming increasingly popular in San Mateo, providing homeowners with a versatile solution to expand their living space, generate rental income, or accommodate family members. we’ll explore the benefits of building an ADU, the factors that influence the cost, and why choosing the best ADU construction services in San Mateo is crucial for a successful project.

ADU San Mateo

What is an ADU?

An ADU, also known as a granny flat, in-law unit, or secondary dwelling unit, is a self-contained living space located on the same property as a single-family home. ADUs can be attached to the main house, detached, or even converted from existing spaces like garages or basements.

The Benefits of Building an ADU in San Mateo

Increased Property Value: Adding an ADU can significantly increase the value of your property. Potential buyers often see the added living space as a major asset, which can lead to a higher resale value.

Rental Income: Renting out an ADU can provide a steady stream of income, helping to offset mortgage payments or other expenses. This is particularly beneficial in high-demand rental markets like San Mateo.

Versatile Living Space: ADUs offer flexible living arrangements, ideal for accommodating aging parents, young adults, or guests. They can also serve as a home office, studio, or short-term rental unit.

Sustainable Living: ADUs are typically smaller and more energy-efficient than traditional homes, contributing to a smaller carbon footprint and more sustainable living.

Factors Influencing the Cost of ADU Construction in San Mateo
The cost of building an ADU in San Mateo can vary widely based on several factors:

Size and Type of ADU: The size of the ADU and whether it is attached, detached, or a conversion will significantly impact the cost. Larger, detached units are generally more expensive to build.

Quality of Materials: High-end materials and finishes will drive up the cost compared to more budget-friendly options. However, investing in quality materials can enhance the durability and appeal of the ADU.

Site Conditions: The condition of the site, including the slope, soil quality, and accessibility, can affect the cost of construction. Challenging site conditions may require additional work and expense.

Permits and Fees: Obtaining the necessary permits and paying associated fees can add to the overall cost. The process can vary depending on local regulations and the complexity of the project.

Labor Costs: The expertise and reputation of the contractor can influence labor costs. Skilled contractors with a history of successful ADU projects may charge more but often deliver superior results.

Average Cost of ADU Construction in San Mateo

On average, the cost of building an ADU in San Mateo ranges from $150,000 to $300,000. Here’s a breakdown of what you might expect:

Basic ADU ($150,000 – $200,000): This includes constructing a smaller, simple ADU with standard materials and finishes.
Mid-Range ADU ($200,000 – $250,000): This includes building a larger ADU with mid-range materials, upgraded fixtures, and more custom features.
High-End ADU ($250,000 – $300,000+): This encompasses a high-end ADU with premium materials, custom designs, and additional features such as green building elements or luxury finishes.

Tips to Save on ADU Construction

While building an ADU can be a significant investment, there are ways to manage costs without compromising on quality:

Plan and Budget: Having a clear plan and budget in place can help you avoid unexpected expenses and keep the project on track.
Choose Cost-Effective Materials: Opt for materials that offer a good balance between quality and cost. Look for sales and discounts on building supplies.
DIY Where Possible: If you have the skills, taking on some of the work yourself, such as painting or landscaping, can reduce labor costs.
Reuse and Recycle: Using salvaged or refurbished materials can add character to your ADU while saving money.
Choosing the Best ADU Construction Services in San Mateo
To ensure your ADU project is successful, it’s crucial to choose the right contractor. Here’s what to look for:

Experience and Expertise: Look for a contractor with extensive experience in ADU construction and a portfolio of completed projects.
Reputation: Check online reviews and ask for references to gauge the contractor’s reliability and quality of work.
Licensing and Insurance: Ensure the contractor is licensed and insured to protect yourself from potential liabilities.
Transparent Pricing: A good contractor will provide a detailed estimate and be transparent about any potential additional costs.


Building an ADU in San Mateo is a smart investment that can enhance your property’s value, provide rental income, and offer versatile living solutions. By understanding the costs involved and carefully planning your project, you can create a beautiful, functional ADU that meets your needs. Whether you’re looking for a basic unit or a luxurious addition to your property, the key is to choose a reputable contractor who can bring your vision to life. With the right approach, your dream ADU is within reach.

Leave a Reply

Your email address will not be published. Required fields are marked *