ADU GUIDE

Home Addition Cost Bay Area and Los Angeles | Cottage

Home addition costs can be high in the Bay Area and Los Angeles. Read how working with an all-in-one designer and builder can save time and money.

CottageJanuary 01, 2018

Owning a home in the Bay Area or Los Angeles is an accomplishment in and of itself. But, what if you need more space?

Before you decide to buy again in an extremely competitive and expensive real estate market, you might want to consider working with the space you already have by building a home addition. A home addition is a cost-effective solution that allows you to maximize both your existing space and your money.

Why Build a Home Addition in the Bay Area and Los Angeles?

Home additions can be costly, especially in the Bay Area and Los Angeles. So, why would a home addition be worthwhile?

Here are some reasons why you may want to consider building a home addition in the Bay Area and Los Angeles:

  • Multi-generational housing: Home additions can provide multi-generational housing. For example, a home addition can provide living space for aging parents that would otherwise need to live in expensive assisted living facilities.

    A home addition can also provide living space for adult children that would otherwise struggle to afford rent or a mortgage in the pricey Bay Area and Los Angeles. Home additions provide family members with their own space while also keeping them close to home.
  • Extra income: Home additions can also provide you with extra income if you rent them out. Housing is in high demand in the Bay Area and Los Angeles, and many people would love to live in a small but efficiently-designed addition unit.

    The Bay Area and Los Angeles are also popular vacation destinations ideal for shorter-term vacation rentals. Just make sure to check the rules and regulations in your area to determine if you can rent out your home addition, either on a short-term or long-term basis.
  • Extra space: If you don’t need more space for extended family members or extra income, perhaps you need more space just for yourself. Many homes in the Bay Area and Los Angeles can be small with limited living space.

    So, rather than feeling cramped in your house, you can build a home addition to provide you with extra entertaining and hosting space. That way, you can comfortably host dinner parties and guests in a dedicated space.

How Much Does a Home Addition Cost in the Bay Area and Los Angeles?

It’s no secret that construction in the Bay Area and Los Angeles is often costly. There are several options for every unique budget. While costs vary depending on the design and features of the unit, you can generally expect to pay the same thing or less than you would pay for a new construction home.

In the Bay Area and Los Angeles, this can range from $300 to $500 per square foot. Keep in mind that this amount also covers fees and permits that can be costly and can quickly make up 10 to 15% of your total budget. Design and professional services can also make up about 15% of your total budget.

The cost of a home addition also varies depending on the type of addition. For example, building an attached addition to your home, also known as an attached ADU if it has a bedroom, bathroom, and kitchenette area, will typically cost less than building a detached addition or detached ADU. This is because detached ADUs often require more site work, utilities, grading, and excavation compared to attached ADUs that can simply use the utilities from the main house.

And while it may be tempting to choose a prefabricated home addition, this might not actually be the most cost-effective option. This is because prefabricated home additions come with a basket of hidden upcharges that add up quickly. So, while you may begin with a cheaper addition, at the end of the day, you’re paying more for lower-quality results. Our team analyzes this topic of prefab ADU vs. modular ADU vs. custom ADU in more detail here.

What Are Home Addition Regulations in the Bay Area and Los Angeles?

In addition to cost, you also need to consider regulations when deciding to build onto your home in the Bay Area and Los Angeles. Different municipalities throughout the Bay Area and Los Angeles have different regulations for home additions. Make sure to consider the different home addition regulations in varying Bay Area and Los Angeles municipalities.

Take a look at these statistics when making an informed decision about whether or not building a home addition would be worthwhile:

San Francisco

Single-family homes in San Francisco are eligible for one ADU and one junior ADU (JADU) of up to 850 square feet for a one-bedroom detached ADU, 1,000 square feet for a two-bedroom detached ADU, or 500 square feet for a JADU.

These units can be up to 16 feet tall and must have a minimum setback of four feet. They do not need to be owner-occupied through 2025, although short-term rentals of less than 30 days are not permitted.

San Jose

Single-family homes in San Jose are eligible for one ADU and one JADU. Lots under 9,000 square feet can build detached units up to 800 square feet. Lots above 9,000 square feet can build detached units up to 1,200 square feet.

These units can be up to 18 feet tall for a one-story detached unit or 24 feet for a two-story detached unit with a minimum setback of ten feet on the street side.

Oakland

Single-family homes in Oakland are eligible for one ADU and one JADU of up to 850 square feet for a one-bedroom detached ADU, 1,000 square feet for a two-bedroom detached ADU, or 500 square feet for a JADU. These units can be up to 16 feet tall and must have a minimum setback of four feet from the side and rear lot lines and six feet from any existing structures.

Palo Alto

Single-family homes in Palo Alto are eligible for one ADU and one JADU at least 150 square feet in size and no more than 800 square feet. These units can be up to 16 feet tall with four-foot setbacks from the side and rear lot lines and six-foot setbacks from any existing structures.

Redwood City

Single-family homes in Redwood City are eligible for one ADU and one JADU of up to 500 square feet for a JADU, 850 square feet for a one-bedroom ADU, 1,000 square feet for a two-bedroom ADU, and 1,200 square feet for an ADA-compliant ADU.

These units can be up to 16 feet tall with minimum setbacks of four feet from the side and rear lot lines and six feet from any existing structures.

Los Angeles

Single-family homes in Los Angeles are eligible for one ADU and one JADU of up to 500 square feet for a JADU, and up to 1,000 square feet for a detached ADU.

These units can be up to 16 feet tall with minimum setbacks of four feet from the side and rear lot lines and six feet from any existing structures.

How Do You Start Building a Home Addition in the Bay Area or Los Angeles?

Home construction is heavily regulated for safety standards. It’s best to ask for help; find someone to help you design and build the addition since this isn’t really something that you should DIY.

Some people take a design-bid-build approach wherein they work with one company to design the unit before getting bids from different professionals to complete different components of the addition, including plumbing, electricity, floors, cabinets, etc.

However, this might not be the best approach. Not only can this approach be costly, but working with numerous different people can get really complicated—many who have tried this route have ended up calling this work a full-time job on its own

Custom ADUs in the Bay Area and Los Angeles

For a simplified and cost-efficient approach, you should consider working with an all-in-one ADU designer and builder like Cottage. Cottage handles every aspect of your home addition build from start to finish for all ADU projects in the Bay Area and Los Angeles.

We start with feasibility to determine the best type of home addition based on your property, goals, and budget. From there, you will work with one of our experienced designers to develop custom architectural plans for your addition. Then, you will select the finishes that work with both your style and budget.

Before moving forward, we prepare your home addition permit application and work directly with the city to expedite your permits. Since we regularly work in the Bay Area and Los Angeles, we are very familiar with the different regulations in the different municipalities and can help streamline and expedite the process.

Once your permits are approved, we break ground and work with pre-vetted professionals to complete the project according to your design and budget. Our contracting partners have been fully vetted to join the Cottage network, unlocking savings and saving you the hassle of managing the difficult process yourself.

Building on the Future

To get started on your home addition with Cottage, schedule a complimentary consultation. This can either be done over the phone or on-site. During this consultation, we can help you figure out how to make the most of your space and provide you with a ballpark cost estimate.

Reach out today so that you can get the extra space you need in no time.

Sources:

Is the Bay Area Experiencing “One of the Most Ferocious Markets in History”? | The Real Deal

Multigenerational Households on the Rise. Prepare for Pros and Cons | USA Today

Want to Rent Out Part of Your Home? Here’s What to Know | The Washington Post

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