How Much Does It Cost to Add 500 Square Feet to a House in Los Angeles?

In the vibrant city of Los Angeles, the prospect of expanding your living space by adding 500 square feet to your home sparks both excitement and financial considerations. This guide delves into the essential aspects of this endeavor, aiming to demystify the costs and choices associated with such a significant project. We’ll explore how much a 500 square foot addition costs, what the process of adding one looks like, who you’ll need to work with, and more.

Here at GreatBuildz, a free service that connects homeowners in Los Angeles, Ventura, and Orange County with reliable home addition contractors, we help homeowners navigate their home addition projects every day. Contact us to get more information on the costs of a 500sf addition… at 818-317-3567

add 500 square feet kitchen

How Much Does It Cost to Add 500sf to Your Home in Los Angeles?

Adding 500 square feet to your home in Los Angeles comes with various cost factors. Firstly, the room size significantly influences expenses, ranging from $150,000 to $250,000 for a 500 sq.ft. addition, with an average of $385.00 per square foot for a room addition in Los Angeles.

The type of room can also impact costs; a master bedroom or family room is generally less expensive than kitchens or bathrooms due to added expenses like plumbing and cabinetry. A mid-priced bathroom in Los Angeles may cost $30,000-$50,000, while a high-end one can reach $55,000-$75,000.

Consider the room level; ground floor additions differ from stand-alone structures, each requiring specific considerations for foundation work and permitting. As we’ll explore further below, second-story additions can double the budget, involving complex demolition, structural issues, engineering plans, and potential relocation during construction.

500 square foot addition construction

Major Costs That Go Into Building a 500sf Addition

Here are some of the major costs that go into building a 500-square-foot addition:

  • Construction materials: Lumber, framing materials, insulation, drywall, siding, roofing materials, etc.
  • Labor costs: General contractor fees, construction crew wages, subcontractor fees for specialized tasks.
  • Foundation work: Excavation, concrete pouring, footings, and any necessary reinforcement.
  • Architectural and design fees: Payments to architects or designers for creating detailed plans.
  • Permit costs: Fees associated with obtaining necessary building permits from local authorities.
  • Structural engineering: Fees for a structural engineer to assess and ensure the addition’s stability.
  • Plumbing and electrical work: Installation of plumbing and electrical systems in the new space.
  • HVAC systems: Costs associated with heating, ventilation, and air conditioning systems if required.
  • Interior finishes: Flooring, cabinetry, countertops, paint, trim, and other finishing materials.
  • Fixtures and appliances: Costs for items like sinks, faucets, lighting fixtures, and any additional appliances.
  • Site preparation: Clearing, grading, and preparing the construction site for the new addition.
  • Landscaping: Restoration of the landscape around the new addition, including any necessary adjustments or improvements.
  • Demolition (if applicable): Costs associated with removing existing structures or parts of the house to make way for the addition.
  • Contingency fund: An allocated percentage (usually 10-15%) of the total budget for unforeseen expenses or changes during construction.


500 square feet addition steel

Building Out Versus Up

When contemplating a home expansion, the choice between building out horizontally or adding a second story involves crucial considerations. Building out, or expanding horizontally, is often less complex and more cost-effective. It requires less structural modification and may seamlessly blend with the existing architecture. However, it utilizes valuable yard space.

On the other hand, adding a second story involves a more intricate process and a higher price tag. This option necessitates reinforcing the foundation, addressing structural concerns, and potentially redesigning the roof. While it may be more expensive, a second story allows for maximizing living space without sacrificing yard area, making it a strategic choice in densely populated or land-constrained areas.

The decision often hinges on local zoning regulations, budget constraints, and the homeowner’s preferences. Building out suits those with ample land, while adding a second story is beneficial for those seeking to preserve outdoor space. Both options require careful planning and consideration of the structural implications, aesthetic cohesion, and long-term utility of the addition to ensure a harmonious integration with the existing home.

add 500sf two story

Process and Timing of Building a 500 square feet Addition

The process and timing of building a 500-square-foot addition involve several sequential steps and can vary based on factors like complexity, permits, and contractor availability. 

Firstly, conceptualize your vision and engage with an architect or designer to create detailed plans. Next, obtaining necessary permits from local authorities is a process that can take several weeks.

Once permits are secured, the construction phase begins. Site preparation, including excavation and foundation work, marks the initial stage. The framing, roofing, and exterior work follow, setting the structural foundation. Next, plumbing, electrical, and HVAC systems are installed before insulation and drywall. Interior finishes, such as flooring and cabinetry, come next, leading to the final touches like painting and trim work.

The timeline for a 500-square-foot addition can range from a few months to a year, depending on factors like weather, the complexity of the project, and unexpected delays. Effective coordination with contractors, adherence to the established schedule, and responsive decision-making by the homeowner contributes to timely completion. Regular communication with the construction team and flexibility in accommodating unforeseen challenges is crucial for a successful and efficient building process.

Which Professionals to Hire When Planning a Major Addition

Planning a major addition to your home involves hiring a team of skilled professionals to ensure a successful and well-executed project. These include:

  • Architect or designer: These professionals translate your vision into detailed plans, considering both aesthetics and functionality. 
  • Structural engineer: These engineers assess the impact of the addition on the existing structure and ensure it meets safety standards.
  • General contractor: GCs oversee the construction process, coordinating various aspects such as permits, subcontractors, and project timelines. Hire a reputable builder or construction firm with experience in similar projects. A skilled contractor will manage the day-to-day operations, ensuring that the project stays on schedule and within budget.
  • Interior designer: Turn to these for guidance on finishes, fixtures, and overall aesthetics to enhance the new space’s visual appeal. 
  • Additional professionals: Depending on the scope, consult with specialized professionals such as HVAC contractors, electricians, and plumbers for the installation of necessary systems.

A successful home addition requires working with the right contractors with the experience and skills to bring your vision to life. GreatBuildz is dedicated to helping our clients find the perfect partners for their needs. Just reach out to us to be matched with one of our trusted, pre-vetted contractors in the Los Angeles and Southern California areas. Contact GreatBuildz today at (818.317.3567) or visit our website for more information.

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.

How can we help with your project?

Explore More Remodeling Topics

Remodeling Cost Guides

Cost Guides

design ideas

Design Ideas

Finding a Contractor

Finding a Contractor

Picking Materials

Selecting Materials

remodeling advice

Remodeling Advice

room addition project articles

Home Additions

kitchen Remodeling Guidance

Kitchen Remodeling


bathroom remodeling advice

Bathroom Renovations

adu and garage conversion blog topics

ADU Construction

backyard Remodeling Projects

Backyard/ Exterior

general home remodeling resources

Home Remodeling