Building a Guest House in the Backyard

Can I Build a Guest House in the Backyard?

Yes, in many cases, you can build a guest house in your backyard. Guest houses are also commonly referred to as accessory dwelling units (ADUs), mother-in-law suites/in-law suites, granny flats, tiny homes, or casitas. These terms all describe the same type of secondary housing unit, though the rules and regulations for each may vary slightly depending on local zoning codes.

Expert planning ensures your guest house complies with setbacks, zoning, and lot coverage while maximizing usable space.

Whether or not you can build one on your property depends on several factors, including:

• Zoning regulations Your property must be zoned for residential use, and some areas may have additional restrictions, especially if you are outside of a designated Transit Priority Area (TPA)​.
• Lot coverage Even though guest houses can be up to 1,200 square feet, the total coverage of all structures on the lot usually cannot exceed 50-60% of the total lot area​.
• Setback and height limits Local codes often require minimum distances from property lines and may restrict the height of the structure​.
• Permitting You’ll need to secure permits and ensure your plans comply with building codes, safety standards, and utility requirements​.

Maximize Space Utilization

A guest house can transform underused yard space into additional livable square footage. It opens up the potential to repurpose existing structures like garages or sheds on the property.

Versatile Uses

A guest house can be perfect for multigenerational living, offering privacy for aging parents or adult children. It’s also ideal for visitors or short-term rentals. Additionally, the space can be used as a home office or studio.

A versatile guest house adapts to your needs—whether for rental income, family use, or a dedicated workspace.

Long-Term Investment

Well-designed guest houses can significantly increase property value, often exceeding construction costs. They offer potential rental income to offset mortgage expenses or recoup building costs. Additionally, properties with guest houses typically have higher resale values.

Key Considerations for Building a Guest House

When planning to build a guest house, you should first define its primary purpose as this decision will inform many aspects of the project. The intended use of the space significantly impacts its design, features, and even legal requirements.

Purpose and Usage

What is the primary purpose and usage of the guest house? Having a clear understanding of this will help greatly during the design phase.

For example, many homeowners use guest houses to generate rental income, either through long-term tenants or short-term vacation rentals. In these cases, homeowners should design with rental appeal in mind—this includes considering private entrances, a full kitchen, and laundry facilities.

Some homeowners build guest houses to accommodate multigenerational living, such as providing housing for aging relatives or adult children. In this case, homeowners can add accessibility features like wider doorways and a walk-in shower to ensure the space suits their elderly relative’s needs.

Others may use guest houses as home offices or studios, where adaptable spaces allow for future changes in function, such as transitioning into a rental unit. Lastly, for those who host frequent guests, a guest house designed with extra bedrooms, a kitchenette, and a private bathroom can offer privacy and comfort for visitors without intruding on the main house.

Purpose defines design. This layout prioritizes functionality for long-term rentals, balancing tenant comfort with ROI.

Zoning and Permits

For a successful project, thorough research on local zoning regulations is necessary. Common misconceptions are assuming the rules are the same everywhere, not realizing the possible need to upgrade electrical or plumbing systems, or underestimating the time it takes for the permitting process.

San Diego requires a building permit for all building types, including a secondary structure. Luckily, the city has implemented a streamlined process where you can apply for a Combination Building Permit that allows multiple disciplines to be submitted simultaneously, such as electrical, plumbing, and architectural to be on one application.

Our expertise in zoning and permitting simplifies the process, ensuring your project complies with all regulations.

How Much Does it Cost to Build a Guest House in the Backyard?

You’ve decided to pursue the project—win! But now you need to know what it will cost. Generally, you can expect to spend around $200-$500 per square foot.

Budget and Cost Estimation

When budgeting for a guest house, you need to consider materials, labor, permitting fees, and possibly legal fees. In San Diego, permit fees can range from $1,000 to $5,000.

Based on our experience helping homeowners throughout San Diego County, here’s a look at typical costs per square foot for an ADU:

• 400 – 500 sq ft around $450 per sq ft
• 501 – 700 sq ft about $425 per sq ft
• 701 – 1000 sq ft roughly $400 per sq ft
• 1001 – 1200 sq ft closer to $390 per sq ft

As you can see, costs per square foot go down as the ADU size goes up. This is all about economies of scale – the larger the project, the more efficiently we can allocate certain costs, which helps bring down the price per square foot. And here’s something we’ve found: by going bigger, you open up options to add a Junior ADU (JADU) or even a bonus JADU, giving you additional living space and further cost efficiency.

Keep in mind, every home is unique, and location plays a big role in costs. For example, building on a sloped lot will impact your overall budget. While cost per square foot is a helpful guide, your property’s specific characteristics will shape the final budget. We’re here to ensure you get the best value, tailored to your vision and needs.

Comparing Costs

The average cost to build a guest house in San Diego is $200-$500 per square foot compared to the national average of $100-$350 per square foot. It’s generally more expensive in San Diego than in many other parts of the country—this is primarily due to the high cost of living and desirable location. Higher building costs are in part due to labor as well as material sourcing.

Planning for Utilities and Amenities

Planning for plumbing and electrical needs should be considered from the outset of the project. This early consideration can save significant time and money during construction.

Plumbing and Electricity

Consider connecting to the main house’s system if possible. For plumbing, it is more efficient to lay out the plan so that the bathroom and kitchen share a common wall or are near each other for water supply and drainage lines. For electrical, the guest house may require the installation of a separate electrical panel to handle the increased loads.

Heating and Cooling

Efficient heating and cooling are essential for comfort, but also energy savings. One option to explore is a ductless mini-split system, which can provide heating and cooling and work well in smaller spaces. San Diegans may prioritize more effective cooling solutions because of the naturally warmer climate.

Green Building Materials

Incorporating green building materials can reduce the environmental impact of your guest house and potentially lower long-term operational costs. Some easy ones to incorporate are energy-efficient windows and doors to minimize heat gain as well as water-saving fixtures to reduce water consumption. Using materials that are recycled or come from sustainable practices such as sheep wool for insulation is a great option.

Designing Your Ideal Backyard Guest House

Now the fun part! Let’s talk about designing your backyard guest house.

Architectural Styles

When designing a guest house in your backyard, you can explore various architectural styles that can complement your main home or create a unique standalone statement. The choice is yours.

Will you decide to be a modern minimalist with clean lines and large expansive windows overlooking your yard? Or will you choose a more traditional look with a pitched roof and classical detailing throughout? Perhaps a Scandinavian-inspired guest house with warmer materials or a Spanish-style ADU with terracotta roof tiles fits your aesthetic better.

Choosing a complementary architectural style, like this Spanish-inspired design, enhances your property’s aesthetic and value.

Space Optimization

Maximizing a guest house’s limited layout can be a fun design challenge. Utilizing vertical area for sleeping quarters and adding built-in storage to the walls or under stairs are great ways to optimize space. An open floor plan is also a solid idea because it will help the entire place feel larger. If your property has the space, adding a deck or patio will increase the square footage and enhance the vibes.

Privacy and Comfort

When designing, you should think of ways to enhance privacy and comfort. This can start by strategically choosing where you’ll place the guest house on your property. You can also design a private entrance and incorporate soundproofing measures. If the guest house can have an outdoor space, you can build a privacy screen by using creative landscaping to give the space privacy from the main residence.

Strategic landscaping and private entrances make guest houses feel welcoming while maintaining separation from the main home.

Construction Options for a Backyard Guest House

Construction for a backyard guest house typically falls into three main categories: custom builds, prefabricated structures, and conversions of existing spaces. The following table displays the advantages and disadvantages of each of these options.

Custom Build vs. Prefabricated

Converting Existing Structures into a Guest House

Converting an existing structure, like a garage or shed, is often a cost-effective way to add a guest house. This option usually involves fewer permits and faster timelines.

However, converting a structure does come with some additional considerations:

• Insulation and Climate Control Most garages or sheds will need substantial insulation upgrades to become comfortable living spaces.
• Structural Integrity It’s essential to check the building’s structure and stability, especially for older constructions.
• Plumbing and Electrical Upgrades may be needed to support plumbing and electrical systems, depending on the current setup.

Choosing and Hiring the Right Contractor

Finding the right contractor is critical to ensuring a smooth project.

Here are a few tips for choosing the best fit:

• Align on Timeline Make sure the contractor’s availability matches your project timeline.
• Discuss Budget and Experience Request a cost estimate and ask about their experience with similar projects.
• Verify Credentials Check for licenses, insurance, and qualifications to ensure they’re fully certified to work on your project.

With the right planning and team in place, building a backyard guest house can be a rewarding investment that adds lasting value to your home.

Get a Free Estimate for Your Backyard Guest House

Take your first steps toward your backyard guest house by getting a free, personalized estimate made with your specific needs in mind. Our team of experts at Better Place is ready to guide you through every phase of the project!