Tiny House ADU

tiny house with a pitch roof in the twilight

ADU as Tiny House

What Can Tiny Houses Teach Us about ADUs?

7min read
by Olesia Chikunova, ADU Specialist.

exterior of a tiny house on wheels
Image by author - Tiny Homes Fest, March 2023, San Diego

Beautiful tiny homes are an inspiration for downsizing and tiny living. The reason to drop everything and go down to San Diego to check them out in person. Even for me, who used to live in a 800 sq. ft. two-bedroom apartment with three kids. (Yes, you can ask me how.)

Tiny houses are also an inspiration for an accessory dwelling unit if it has to be tiny. Some backyards have so many limitations that we have to build a tiny house. Tiny house movement offers a unique style solution to the housing crisis.

Tiny Houses Are Not so Tiny!

Have a look at the number of people touring this tiny house!
not so tiny house
Image by author - Tiny Fest, March 2023, San Diego

How small are tiny houses?

Tiny houses are generally smaller than traditional houses. They are designed to maximize space efficiency while providing a functional living space. The size of a tiny house can vary depending on the design, layout, and individual needs. However, most tiny houses are between 100 and 400 square feet. Some tiny houses may be as small as 80 square feet, while others can be up to 600 square feet or more. The exact size of a tiny house will depend on factors such as the number of occupants, lifestyle needs, and budget. Despite their small size, tiny homes can still offer all the necessary amenities for comfortable living, including a kitchen, bathroom, sleeping area, and living space.

ADU vs. tiny house

While there is some overlap in the definition of a tiny house and an accessory dwelling unit (ADU), there are also some key differences between the two.

A tiny house is typically a standalone structure designed to be highly compact, usually between 100 and 400 square feet. Tiny houses can be built on a permanent foundation or on wheels and are often designed to be mobile or easily transportable.

On the other hand, an accessory dwelling unit (ADU) is typically a smaller, secondary dwelling unit built on the same property as a primary residence. ADUs can be attached or detached from the primary residence and are often used as additional living space for family members or as rental units.


How small can an ADU be?  The smallest ADU in California is 150 sqft.

Some of the critical differences between tiny houses and ADUs include the following:

1.    Size: While tiny houses are typically between 100 and 400 square feet, ADUs can be larger, usually up to 1,200 square feet, depending on local regulations.

2.    Location: Tiny houses can be located on their own piece of land, while ADUs are typically built on the same property as the primary residence.

3.    Mobility: Tiny houses are often designed to be mobile or easily transportable, while ADUs are typically built on a permanent foundation and cannot be easily moved.

4.    Purpose: Tiny houses are often used as primary residences. ADUs are typically used as additional living spaces for family members or as rental units.

Overall, while both tiny houses and ADUs are compact living spaces, there are some key differences between the two in terms of size, location, mobility, and purpose.


Is a tiny house considered a dwelling?

Yes, a tiny house is considered a dwelling as it is where someone lives and can be used as a primary residence. In many places, tiny houses are legally classified as a type of dwelling, just like a traditional house or an apartment. However, the specific regulations and definitions of a dwelling can vary depending on the location and the local building codes. Some areas may require minimum square footage, plumbing, electrical, and heating systems for a structure to be considered a dwelling. It’s essential to research and comply with your area’s building codes and zoning regulations if you plan to build a tiny house as a dwelling.

Can a tiny house be an ADU? Yes.

Where are tiny houses legal?

Can you put a tiny house on a residential lot? Where are tiny houses allowed? 

The laws and regulations surrounding tiny houses vary by country, state, and city. In the United States, no federal law defines what a tiny house is or regulates its construction. This means that regulations and building codes for tiny homes can vary widely from place to place. Some counties and states have specific laws and regulations allowing tiny houses, while others do not.

Some areas in the United States have welcomed tiny house living and have developed specific regulations to accommodate them. For example, Spur, Texas, has become known as the “tiny house friendly” town due to its particular regulations allowing tiny houses on wheels. In California, the cities of Fresno and San Diego have created specific rules to allow accessory dwelling units (ADUs), which can include tiny homes.

It’s important to research and understand the laws and regulations in your specific area before considering building or living in a tiny house. This helps ensure you comply with local laws and avoid potential legal issues.

kitchen in a tiny house
Image by author - Tiny Homes Fest, March 2023, San Diego

How to build a Tiny House?

Any experienced builder will offer the following advice to future tiny house owners:

1.    Building codes: The first thing you must be aware of is the building codes in your area. Depending on where you live, there may be specific codes and regulations that you need to follow when building a tiny house. Researching and complying with these codes is essential to avoid any legal issues.

2.    Budget: Building own tiny house can be cost-effective, but having a budget in mind is crucial before starting. Be sure to account for all the expenses, such as materials, labor, and permits, to avoid running out of money halfway through the project.

3.    Design: Designing your tiny house is crucial to ensure it’s functional and meets your needs. Consider the layout, storage space, and amenities you want to include. Browse online tiny house floor plans to select one with those standard features that matter to you most. Keep in mind, that standard models offer most affordable prices. 

4.    Materials: Choose durable, energy-efficient, and cost-effective materials. Since you’re working with limited space, you want to make the most of it, so selecting the right materials is essential. Think about energy efficiency. Does it make sense to add solar power?

5.    Tools: You’ll need various tools to build your tiny house. Basic tools like hammers, saws, and screwdrivers are essential. Still, you may also require specialized tools like a circular saw or a power drill.

6.    Permits: Depending on your location, you may need to obtain permits before building your tiny house. These permits may include zoning permits from a Planning Department, plus building, plumbing and electrical permits from the Building Department. Be sure to research the permit requirements in your area.

7.    Time: Building a beautiful tiny house can take time, so be prepared to commit to the project. Having a timeline in mind and planning for unexpected delays is essential.

Considering these factors, you can build a functional, cost-effective tiny house that meets your needs and complies with local regulations.

container tiny house
Image by author - Tiny Homes Fest, March 2023, San Diego

Who builds tiny houses?

Tiny houses can be built by various people, including professionals in the construction industry and DIY builders. Here are a few examples of who might build tiny houses:

1.    Professional tiny home builders: Many companies and builders specialize in designing and constructing tiny homes. These professionals have the knowledge and experience to build a high-quality tiny home that meets local building codes and regulations.

2.    DIY builders: Many people build their own tiny homes as a DIY project. With the help of online resources, books, and workshops, learning the necessary skills to build a tiny home from scratch is possible. However, it’s important to note that building a tiny home requires significant time, effort, and skill.

3.    Custom builders: Some people work with a custom builder to design and build a tiny home that meets their specific needs and preferences. Custom builders can help with the design and construction process, ensuring that the final product meets the owner’s vision.

4.    Conversion specialists: Some people convert an existing structure, such as a shipping container or a school bus, into a tiny home. These conversion specialists have the knowledge and skills to modify the existing structure to create a comfortable and functional living space.

Regardless of who builds the tiny home, ensuring that the final product is safe, functional, and meets local building codes and regulations is crucial.

tiny house in a car
Image by author - Tiny Homes Fest, March 2023, San Diego

What Makes a Tiny House?

bedroom in a tiny house
Image by author - Tiny Homes Fest, March 2023, San Diego

The must-have features of a tiny house can vary depending on individual preferences and needs. However, here are some general features that most people consider essential in a tiny house:

1.    Multi-functional furniture: Every square inch of space counts in a tiny house, so having furniture that can serve multiple purposes is crucial. Multi-functional furniture includes a bed that can convert into a sofa or a dining table that can fold down when not in use.

2.    Efficient storage: With limited space, maximizing storage opportunities in a tiny house is essential. Creative storage solutions like built-in cabinets, shelves, and under-bed storage can help you keep your living space organized and clutter-free.

3.    Energy-efficient appliances: Energy-efficient appliances can help you save money on utility bills and reduce your environmental impact. Consider investing in appliances like a mini-fridge, an induction cooktop, and a tankless water heater designed for small spaces. Please make sure they are energy efficient too. 

4.    Natural light: Maximizing natural light in a tiny house can make the space more open and spacious. Consider installing large windows or skylights to bring in as much natural light as possible.

5.    Loft space: A loft space can provide additional living space in a tiny house, whether for sleeping, storage, or a workspace. A loft can also create a separation between the sleeping area and the rest of the living space.

These are just a few examples of the must-have features in a tiny house. Ultimately, your chosen features will depend on your needs, budget, and personal preferences.

loft sleeping space in a tiny house
Image by author - Tiny Homes Fest, March 2023, San Diego

Why are tiny homes on wheels less expensive than those built on permanent foundations?

A lot has been written about costs to build a tiny house. Tiny homes on wheels are often less expensive than tiny homes built on a permanent foundation for a few reasons:

1.    Lower land cost: With a tiny home on wheels, purchasing land for a permanent foundation is unnecessary. This can significantly reduce the cost of the overall project.

2.    Fewer materials: Since tiny homes on wheels are smaller, they require fewer building materials than larger homes. This can reduce the overall cost of the build.

3.    Mobility: With a tiny home on wheels, the homeowner can move the home to different locations, eliminating the need for a separate vacation or rental property. This can also reduce the cost of owning and maintaining multiple properties.

4.    Fewer utility hookups: Tiny homes on wheels may require fewer utility hookups than a traditional home, such as water, sewage, and electrical connections. This can reduce the cost of installation and ongoing utility bills.

5.    DIY construction: Many tiny home builders choose to construct their homes themselves, which can save on labor costs. With a tiny house on wheels, it may be easier to build on your own since it can be done in a smaller space and moved to a new location as needed.

Overall, tiny homes on wheels are often less expensive than homes built on a permanent foundation due to the lower land cost, fewer materials required, mobility, fewer utility hookups, and the possibility of DIY construction. However, it’s important to note that the cost of a tiny home can vary widely depending on the design, materials used, and other factors.

One more thought to consider: an appraiser will appraise a tiny house on wheels as personal property. Tiny house foundations turn them into real estate.

A tiny house does not have to be on wheels. A lot of tiny house builders offer a service to bring the house to you on wheels and then transfer to permanent foundation. Or semi-permanent foundation. Imagine, there are foundations, that you can screw in when you need them and screw out when you do not.

tiny house on wheels
Image by author - Tiny Homes Fest, March 2023, San Diego

Design ideas for small homes

An interior designer will offer the following design ideas for small homes:

1.    Use light colors: Light colors, especially whites, and light grays, can make a small space appear larger and brighter. You can use light colors on the walls, ceiling, and floors to create a cohesive and open look.

2.    Maximize natural light: Natural light is essential in making a small space feel open and airy. Use sheer or light-colored window treatments to allow as much natural light as possible to enter the room. If privacy is a concern, consider installing frosted or textured glass or using window films.

3.    Embrace minimalism: In small spaces, clutter can quickly accumulate and make the area feel cramped. Embracing minimalism by using only necessary furniture and decor can help to create an open and uncluttered feel.

4.    Use multi-functional furniture: A sofa bed or a storage ottoman can serve multiple purposes in a small space. This can save space and make the room feel more open.

5.    Incorporate mirrors: Mirrors can create an illusion of space and light in a small room. Place a large mirror on one of the walls to reflect light and create the illusion of a larger area.

6.    Utilize vertical space: In a small room, it’s important to use every inch of available space. Utilize vertical space by installing tall bookcases, shelves, or storage cabinets. This helps maximize storage space while keeping the room clutter-free.

7.    Use scale appropriately: When selecting furniture for a small space, it’s vital to use scale appropriately. Choose furniture that is correctly sized for the space, and avoid pieces that are too large or heavy for the room.

By incorporating these design ideas, you can create a functional and visually appealing small home that maximizes the available space while providing all the necessary amenities for comfortable living.

tiny house on wheels
Image by author - Tiny Homes Fest, March 2023, San Diego

Windows drive the tiny house design.

Large windows can make a tiny house feel bigger for a few reasons:

1.    Increased natural light: Large windows allow more natural light to enter the space, making the room feel brighter and more open. This can help to create the illusion of a larger area, as a dark and cramped room can make a small house feel even smaller.

2.    Expands the view: When you can see outside, it can help to expand your perception of the space beyond the walls of the tiny house. This creates a sense of connection to the outdoors and can make the room feel less confined.

3.    Blur the lines between indoor and outdoor spaces: By bringing in more natural light and offering a more expansive view of the surroundings, large windows can blur the lines between the indoor and outdoor spaces. This can make the area feel more spacious and allow you to connect more with nature.

In summary, large windows can make a tiny house feel bigger by increasing natural light, expanding the view, and blurring the lines between indoor and outdoor spaces. This creates a more open and airy feel to the space and can help to make it more comfortable and inviting.


tiny house with Jeldwen windows
Image by author - Tiny Homes Fest, March 2023, San Diego

Sustainable living in your backyard 

Living in a tiny house is often considered sustainable for several reasons:

1.    Reduced energy consumption: A tiny house built to code requires less energy to heat, cool, and light up than a traditional home due to its smaller size. This means less energy consumption, lower utility bills, and a smaller carbon footprint.

2.    Minimalism: Living in a tiny house often requires a simplified lifestyle with fewer possessions and less consumption, which can help reduce the overall environmental impact.

3.    Reduced waste: With limited space, tiny house dwellers must often be mindful of their consumption and waste. This can lead to a more sustainable lifestyle, with less food waste, less use of disposable items, and more recycling and composting.

4.    Use of sustainable materials: Many tiny homes are built with sustainable and eco-friendly materials such as reclaimed wood, recycled steel, and renewable resources like bamboo or cork. This can help reduce construction’s environmental impact and create a healthier living environment.

5.    Mobility: Some tiny homes are built on wheels or designed to be easily transported. This means that the house can be moved to a new location if needed, reducing the need for new construction and minimizing the environmental impact.

Living in a tiny house can be considered sustainable due to reduced energy consumption, minimalism, reduced waste, use of sustainable materials, and mobility. By living a more sustainable lifestyle in a tiny home, people can reduce their environmental impact and contribute to a more sustainable future.

tiny house in homewrap
Image by author - Tiny Homes Fest, March 2023, San Diego
If a tiny house does not work for you

Three more ways to add space

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If all you need is an extra room for an office, then a simple 120 sf backyard structure may work. Starting at $48,000.

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