Ultimate Guide to Building a Second Story Addition in Orange County

In Orange County and Southern California, home prices have reached all-time highs. As a result, many Southern California residents have opted to stay put and improve their quality of life through home renovations rather than moving. As an alternative to purchasing a larger home, some homeowners are adding space to their current residences. This article focuses on the construction of a second-story addition in Orange County.

Here at GreatBuildz, a free service that personally matches homeowners in Los Angeles, Orange County, Ventura & San Diego with reliable general contractors, we talk to homeowners every day about second story addition projects and costs – here are some key points to know.

The Comprehensive Guide to Constructing a Second Story Addition in Orange County

2nd story addition

Adding a second story to an existing home is a practical and popular option to provide additional living space. You will not lose any outdoor yard space with this addition. You will also avoid the onerous processes of selling, purchasing a new property, and relocating to a new place.

Second-story home additions add a full or partial level to a house. Frequently, they require removing the roof, constructing new space, and installing a new roof. In certain instances, however, the builder can extend the upper level across an existing one-story component, such as a porch or garage with a flat roof. Regardless of your preference, it is usually advisable to use a skilled second story builder. The addition, if executed properly, might entirely convert your place into your ideal home.

Orange County Cost of Adding a Second Story

The cost of a second story addition in Orange County varies depending on a variety of factors, including the quantity of space, labor, layout and design, materials, etc. However, on average, it can cost between $400 and $500 per square foot, with a maximum of $700 per square foot. The lowest quote you would likely receive in Orange County is $400 per square foot, which equates to approximately $280,000 for a 700-square-foot second-story. However, based on the above variables, you may pay up to $500,000 or even more.

Other price factors include:

  • Hillside renovations are more expensive since they are typically more difficult to access.
  • A bathroom addition might cost between $30,000 and $50,000.
  • Whether or not the existing home has a slab foundation will impact how challenging it will be to install new plumbing.
  • Whether you’ll need to upgrade your electrical panel to match your higher electricity demands.
  • Cost of residing in a temporary residence during renovations.
  • Whether or not the entire roof must be replaced.

cost of a second story addition

There is no simple way to determine the precise cost of the second story addition, as each home is unique. Therefore, it is advisable to obtain estimates from multiple general contractors in order to determine the cost of the project. To make it easy to compare the cost of every estimated item, each contractor should break down their bid into its individual components. You might also want to interview a few architects to create the plans for the second story expansion.

In Orange County, how long does it take to build a second story addition?

The duration varies depending on the need for foundation work, the timing of materials, permits, the weather, and change orders. Location, terrain, and the condition of the first floor are other factors. However, a complete second story addition can take anywhere between six and nine months. A partial one may span three to five months.

Most homeowners choose to vacate their homes during renovations due to the dust and noise generated. If you intend to relocate too, find out how long the construction will last. Your general contractor should have a good understanding of this. However, if the project involves only a portion of the second floor and the work area can be sealed off, you may be able to remain in your property.

Considerations Regarding the Addition of a Second Story in Orange County

adding a second story

Obtaining Permits for a Second-Story Addition

The majority of second story additions include an additional bedroom and bathroom. Your building permit will therefore contain permits for plumbing, electrical, and mechanical work. Note that the length of time required for permit approval varies by city. In Orange County, for instance, the approval of a permit for a second story extension can take up to 12 weeks. However, in some cities, you can pay for expediting services. As your architect is aware, the second-story addition must comply with the Building Energy Efficiency Standards – Title 24, which minimizes energy waste in new structures.

Understanding Zoning Rules 

Zoning regulations vary by region. Therefore, you must determine if the second story addition complies with zoning regulations in your community. Some cities have recently enacted protections against ‘mansionization’ to restrict architectural styles that do not match those of the area’s original dwellings. Therefore, it is always essential to be aware of these and other concerns, such as powerline clearance. Know that if you live in a Historic Preservation Overlay Zone (HPOZ), your proposed improvement will be reviewed. Assuming they regularly create plans in your area, your architect should be familiar with these requirements and restrictions.

Consider height constraints and whether your intended improvements would obstruct your neighbor’s view. Most cities have height restrictions for homes with pitched and flat roofs. Verify with the local building department that they will approve your project and that your plan doesn’t violate any zoning regulations.

How to Plan Your Orange County Second Story Addition 

planning a second story addition

Locate a Qualified Engineer/Architect 

You need an architect that can incorporate your ideas into a plan that is safe, functional, and suitable to the building department. A professional architect is familiar with building codes and will collaborate with the general contractor to ensure that the project is completed correctly the first time. They will also assist you in creating the ideal design for your needs.

Utilities May Require Upgrading

Since you are expanding the square footage of your home, you will probably need to upgrade electrical panels and plumbing.  Additionally, more ventilation will be required, so you may need to modify or reroute your HVAC system.

Changes to the Foundation

Expect some foundational improvements during construction. The second story area will increase the load on the first level, which will nearly always require reinforcing.

Finding the Right Contractor to Work With When Adding a Second Story in Orange County 

This is possibly the most crucial decision you will make.  A second story addition is not a simple project. It demands experience and knowledge. Therefore, it is in your best interest to work with a contractor that has experience in undertaking projects of this scope. Review the company’s reviews and testimonies, as well as its portfolio, reputation, and years in business.


When it comes to planning and coordinating a second story addition for your home, you shouldn’t have to go it alone – GreatBuildz can help simplify your contractor search. GreatBuildz is a free service that connects homeowners in Los Angeles, Orange County, Ventura & San Diego with reliable, thoroughly screened general contractors and provides project support from start to finish.


Call now (818.317.3567) to chat with our local team about your next renovation project or visit our website for more information: www.greatbuildz.com

Hi, we're Paul and Jon - Co-Founders of GreatBuildz. We believe everyone deserves to find a great contractor, have a stress-free renovation, and enjoy their beautiful new space. There are so many contractors out there and it's often hard to tell the good from the bad... until it's too late. We started our company to help simplify your contractor search and help you have a stress-free renovation experience. We're always available to help, no matter where you are in the process. Click here to learn more about our story.

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