The Key Benefits of Building an ADU on Your Property

House plan sketch

Given today’s unique living conditions, it’s no surprise that more homeowners are looking for ways to increase a property’s value, floorplan area, and even extra income. Building an Accessory Dwelling Unit (ADU) on your property lets you achieve just that.

An ADU is a small, self-contained living unit, built on the same lot as an existing home. With various designs available, an ADU can serve as a rental unit, a guest house, or even a home office. By building on the existing space available, you add another livable area to your property without the expense and hassle of purchasing a new home or relocating.

This additional space has been found to increase the value of your property and provide a significant source of rental income. According to a study by the National Association of Home Builders, an ADU can increase a property’s value by up to 25%.

Whether you are a homeowner looking to generate rental income or a family looking to add an independent living space, an ADU could be the perfect solution. G.J. Gardner Homes is here to explore building an ADU, and how it can help you maximize the benefits of an existing property.

What is an ADU (Accessory Dwelling Unit)?

An Accessory Dwelling Unit (ADU) is like its name suggests: an extra unit built on the land of an existing home. You will find them in the form of a granny flat, carriage house, or even a tiny home. ADUs come in a versatile range of designs to accommodate a wide range of needs, from housing for aging parents to investment property.

The growing design range of ADUs lets you customize the property depending on the specific needs of the homeowner and the unit’s intended function. Fortunately, ADUs can be designed as standalone units with their own entrance and kitchen, or they can be connected to the primary residence via a shared wall or other common area.

The building process of the ADU will come down to the difficulty of the design but in most cases, it’s a convenient and efficient build. G.J. Gardner Homes’ team makes building an ADU a seamless and stress-free experience.

Why should you put an ADU on your property?

ADUs have grown significantly in popularity in recent years, as they become more accessible, convenient, and lucrative.

This year has seen more municipalities relax their regulations around ADUs, making the process even more available for homeowners across the country. The rising prevalence of ADUs lets more American reap its significant range of benefits.

Most notably, ADUs offer an affordable way to add living space to your property without the need for expensive and time-consuming renovations. This living space can be used by the homeowners as an extra bedroom, office, or play area, or rented to tenants and gain the major advantages that come with each.

Additional rental income:

Building an ADU on your property is a fantastic way to generate extra income. Renting out the ADU lets you earn additional monthly income, which can help cover mortgage payments, bills, and other expenses.

Increased property value: 

An ADU can add value to your property, making it more attractive to potential buyers. By increasing the overall square footage of your home and amenities, your property grows more valuable in the real estate market.

Enhanced privacy: 

An ADU can provide a separate living space for family members or guests, allowing for greater privacy and independence. This additional space offers a perfectly private home office, art studio, or guest house.


An ADU can provide a flexible living space that can be adapted to a variety of needs. Whether it’s for aging parents, adult children, or guests, an ADU can be designed to meet the unique needs of each individual.

Sustainable living: 

Building an ADU can also promote sustainable living. Through a smaller living space, you can reduce your carbon footprint for a more eco-friendly lifestyle. Through their range of designs, ADUs can be customized to include energy-efficient features, such as solar panels and high-performance windows as well. 

Get in Touch

Building an ADU is a smart investment for your home now and in the future. Whether you’re looking to generate income or add extra living space, an ADU is a versatile and affordable solution you can customize to your unique needs.

If you’re interested in building an ADU on your property, the friendly and experienced team at G.J. Gardner Homes is here to help. With years of expertise in custom home building, we can guide you through the design and construction process to create an ADU that meets your unique needs and enhances the value of your property. Contact us today to learn more about how we can bring your vision to life.

The Cost of Building an ADU vs. a New Property

Accessory Dwelling Units (ADUs) are becoming an increasingly popular choice for homeowners looking to add living space or rental income to their property. While some may assume that building an ADU is more cost-effective than constructing a brand-new property, it’s important to take into account various factors that can impact the overall cost of both options.

However, there’s a different set of costs associated with building an ADU compared to a new property, as well as the potential benefits and drawbacks of each option. Whether you’re a homeowner considering an ADU or a new build, understanding the cost implications of each choice can help you make an informed decision that meets your needs and budget.

What is an ADU (Accessory Dwelling Unit)?

An Accessory Dwelling Unit (ADU) is a secondary residential unit that can be built on the same property as a primary residence. Also known as a granny flat, backyard cottage, or mother-in-law suite, an ADU is typically smaller than the main house and has its own entrance, kitchen, bathroom, and living space. ADUs are gaining popularity as they provide homeowners with additional living space and rental income, while also helping to address the shortage of affordable housing in many cities.

ADUs come in a variety of styles and configurations, from detached units to those attached to the main house. They can be used as a rental unit, a guest house, a home office, or as a separate living space for aging parents or adult children. ADUs can be designed to complement the architecture of the main house or to stand out as a distinct and modern addition to the property.

How much does an ADU cost to build?

ADUs are increasingly popular among homeowners who want to increase the value of their property, provide extra space for family members, or generate rental income. However, the cost of building an ADU varies depending on the location.

In the United States, the cost of building an ADU can range from $175,000 to $400,000, or more. The cost depends on a variety of factors, such as the size of the unit, the type of construction, and the location. For example, building an ADU in a high-cost city like San Francisco or New York City will be significantly more expensive than building in a more affordable location like Texas or the Midwest.

The cost of building an ADU can also vary based on the type of unit. A detached ADU, which is a separate structure from the primary home, will generally be more expensive than an attached ADU, which is connected to the primary home. Additionally, a custom-designed ADU will be more expensive than a prefabricated or modular unit.

When considering the cost of building an ADU, it is important to factor in additional expenses such as permits, site preparation, and utilities. The cost of utilities can vary depending on the location and the type of ADU. Some homeowners may choose to install solar panels or other energy-efficient features to help offset these costs over time.

How much does a new property cost to build?

Building a new property can be an expensive endeavor. The cost of constructing a new property depends on various factors such as the location, the size, the design, and the materials used.

Building a new property can be a significant investment, and the cost will depend on several factors. The location, size, design, and finishes all contribute to the final cost. According to HomeAdvisor, the average cost of building a new home in the United States ranges from $150,000 to $450,000, with a median cost of around $320,000. However, this again can vary widely based on location, with homes in high-cost areas like California and New York being significantly more expensive.

In addition, the cost of labor and materials can also vary depending on the region, with some areas having higher construction costs due to local regulations and building codes. Other factors that can affect the cost of a new home include site preparation, permits, and the complexity of the design.

What impacts the cost of building

When considering building an Accessory Dwelling Unit (ADU), it’s essential to understand the factors that contribute to the cost. Here are some significant factors that can impact the final cost of building an ADU:

  • Size and layout: The size and layout of your ADU will directly impact the cost of construction. Larger units require more materials and labor, which can drive up the cost.
  • Design and style: ADUs come in many shapes and styles. A more complex design can increase the cost of construction as it will require more time and labor.
  • Location: The cost of construction can vary depending on the location of the property. If you’re building an ADU in a high-cost area, expect to pay more for materials and labor.
  • Foundation: The type of foundation you choose for your ADU can also impact the cost. A slab foundation is generally less expensive than a full basement or crawlspace.
  • Plumbing and electrical: Plumbing and electrical costs can vary depending on the type of fixtures and appliances you want to install.
  • Permits and fees: Building an ADU requires various permits and fees, including construction permits, inspection fees, and impact fees.
  • Labor costs: The cost of labor can vary significantly depending on the location and complexity of the project. It’s essential to work with a reputable contractor who can provide an accurate estimate of labor costs.

By understanding these factors, you can make informed decisions about the cost of building an ADU. Working with a reputable builder who specializes in ADUs can help you manage costs and ensure that your project stays within your budget.

ADUs Vs house extension

When it comes to expanding your living space, you have several options available, including building an ADU or extending your house. Ultimately, the choice between building an ADU or extending your home will depend on your personal preferences and overall goals.

Building an ADU provides an opportunity to create a completely separate living space with its own entrance and amenities. This can be particularly beneficial if you’re looking to generate rental income, accommodate guests or family members, or simply have more privacy.

On the other hand, extending your home can provide a seamless expansion of your existing living space. This option may be more ideal if you’re looking to increase the size of your home while maintaining the same overall layout and aesthetic. Extending your home can also be a better option if you have specific design or architectural preferences that you’d like to incorporate into your expanded space.

Regarding costs, ADUs, and home extensions are priced in a similar range. The average cost of building a house extension in America ranges from $20,000 to $75,000 or more, depending on the size and complexity of the project. This is significantly higher than the cost of building an ADU, which can range from $50,000 to $200,000 or more, depending on location, size, and amenities.

Should you build an ADU or new property?

If you’re stuck in deciding between building an ADU or a new property, don’t hesitate to contact the G.J. Gardner Homes team. Our experienced and knowledgeable team can guide you through the process, helping you make an informed decision that best suits your needs and preferences. With our expertise and commitment to quality, we are dedicated to bringing your dream home to life.

A Guide to Changes to California’s ADU Laws (2023)

Why have the ADU Laws been changed?

Recently, changes were made to Californian ADU laws to incentivize property owners and developers to add these to their existing properties.

The California Legislature found that, among other things, ADUs and JADUs (junior accessory dwelling units) provide additional rental housing in areas that are perfect for single family and multifamily living.

As a result, they have been working to reduce the complexity of the process, encouraging the development of more ADUs to address the region’s evolving housing needs.

Through reducing the legal restrictions on ADUs and streamlining the approval process, homeowners and developers are encouraged to build more ADUs. This has the additional effect of providing more comparatively reasonably priced rentals for the residents of California.

Summary of Changes

The most recent round of changes came from several bills, all in the name of making ADUs more accessible to California residents. Here are some of the key changes for property owners and developers.

AB 345

The amendments to AB 345 have made it possible for ADUs to be sold separately from the home in some cases. Cases include when the ADU was built by a qualified not-for-profit, or is to be held as owner-occupied low-income housing for 45 years.

Note: this doesn’t apply to JADUs.

AB 3182

Amendments to AB 3182 address the approvals process and are designed to make the process more efficient from start to finish.

Primarily, if an ADU or JADU has not been approved by the local agency within 60 days, it will be deemed approved by default. You can now also gain approval for both an ADU and a JADU per lot, rather than needing to select one or the other. It also allows for the leasing or rental of ADUs or JADUs in common interest developments, and ensures 25% of these will be allocated as rentals.

AB 68, AB 881 and SB 13

Amendments to these bills are similarly intended to remove barriers that many people run into when looking to build ADUs.

Changes to these bills are more numerous and include:

  • removing minimum lot sizes for ADU builds,
  • clarifying that ADU requirements can be based on sewerage access, water access and impacts on traffic and public safety,
  • eliminating owner-occupancy requirements,
  • making it impossible for local agencies to enforce a maximum size of less than 850 square feet,
  • allowing converted ADUs (such as renovated garages or carports) to go without replacing on-street parking,
  • reduces the maximum approval wait time from 120 days to 60 days,
  • reduces impact fees,
  • allows JADUs to be constructed within the walls of an existing residence,
  • as well as explicitly clarifying some gray areas that caused confusion to some developers and builders.

AB 587, AB 670 and AB 671

Finally, the changes to the following bills are more related to Health & Safety law that sometimes prohibited the construction of accessory dwelling units.

The amendment to AB 587 creates an exception similar to AB 345, where some ADUs can be sold separately to the original dwelling so long as they adhere to ordinance that specifies the ADU is built by a non-profit for low-income housing.

AB 670 removes restrictions that would’ve unreasonably restricted ADU construction on a lot zoned for single family residential use.

Finally, revisions to AB 671 incentivizes the construction of ADUs for very-low through to moderate level income tenants, as well as pushing California’s HCD to collate resources to better facilitate the construction of these lower income ADUs.

At G.J. Gardner Homes, we’ve got years of experience in building ADUs. If any of the above is unclear, we can help you to work your way through the approvals process, ensuring all is above board and complies to local regulations.

Many areas in California now offer permit ready ADU plans, free for public use. We’ve collated some links below!

Contact us today if you’re interested in building an accessory dwelling unit on your lot.