How to Know if You Can Put a Guest House in Your Backyard

What to know before adding an ADU to your lot

March 12, 2021
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If you’re a homeowner who wants to find out whether or not you can build a prefab guest house in your backyard, you’ve come to the right place. Guest homes and other types of accessory dwelling units are a great investment, but there are a number of steps to take and factors to consider before moving forward with this decision.


Every city has different zoning laws and regulations for accessory dwelling unit development, so it’s important to contact your city’s residential permitting department and read your local zoning code. If your city allows you to build a guest house, this will help you determine whether or not your prospective prefab home fits within legal bounds so you don’t end up running into any costly legal obstacles along the way. With the help of a contractor, this process should go smoothly.


A Brief History of ADUs

An accessory dwelling unit, or ADU for short, is a secondary living space built on the same lot of land as a primary home, such as a basement apartment or tiny house in a backyard. ADUs are either attached or separate from the main home. The most common reasons why homeowners build ADUs, are to house relatives or gain income through rent. Accessory dwelling units cannot be bought or sold separately.


ADUs first became popular when World War II was followed by a growing demand for housing as the suburban population multiplied. Despite zoning restrictions and prohibition, they still continued to be built in communities where demand outweighed the supply of housing. In the 1990s, urban design movements like New Urbanism sought to reduce automobile dependency and make communities more inclusive by providing a wide range of housing options, such as accessory dwelling units. However, changes like this are often met with pushback.


“Not In My Backyard”, or NIMBY, is a term to describe this pushback. This resistance is usually caused by the assumption that allowing low-income people to live in the community will increase violence, theft, litter, etc. Meetings within local communities are held in order to resolve this conflict because of how political it be in neighborhoods.


On the bright side, there is growing acceptance for ADUs. So if you’re someone who is interested in building one in your backyard, here are the steps you should take to determine whether or not this is possible where you live:

Call your city

Before you get started on building an accessory dwelling of your own, there are many legal issues to consider, such as size restrictions and livable setbacks. These regulations will differ depending on the city you live in, so it’s important to contact your local residential permitting department. You can find the number to call by google searching your city’s local residential permitting department number.


Questions to ask:

1) Can I put a secondary home on my lot?

This is the first question you should ask because building an accessory dwelling unit is not legal in every city.

2) What are my livable setbacks, and ADU size regulations?

A setback is the exact distance between fixed points in which building is prohibited. This is a restriction created by local governments in order to prevent crowding other people’s property, make space for pipeline placement, and preserve wetlands.

Your city may require that one or more 'exterior' design features.

3) Can I put a prefabricated guest house on my property?

Prefabricated homes are built in separate sections in a factory then assembled on the building site.  

  • Site built prefab or fully factory-built prefab home?
  • A fully factory-built prefabricated home is one that is built in a factory and then transported to the site, where its construction is completed. However, unless a manufacturer has a state certificate, US cities won’t allow a fully assembled prefab to be craned into your backyard.
  • Site-built prefabricated homes are a great alternative. Instead of the whole home being transported to your backyard, the home is built after all the parts and materials required to build the home are transported to your backyard.  
  • Shorter build times (sometimes only a week) than conventional stick frame homes


Read Your Local Zoning Code for Additional Info

Look up and read your city’s zoning code as well as any additional online pamphlets that thoroughly explain the rules for building accessory dwelling units in your city. These sources are extremely important because they have information about factors such as:

  • Whether or not an extra parking space is required
  • Whether or not the ADU should be attached or separate
  • If the ADU needs to match the exterior appearance of the primary home
  • If an inspection and walk-through is required for your ADU


If how the local zoning code applies to your prospective ADU is still unclear, consider visiting your local planning department for more information and clarification. Another option is to contract with a project manager or architect that is familiar with local zoning regulations, to help you assess these factors before you start building.


Find a Licensed Contractor

A general contractor’s job is to make sure the construction and placement of your prefab guest house is done correctly and in accordance with your local zoning regulations. Some prefab home manufacturers have resources to assist you in finding a licensed and insured contractor in your city. But if they don’t, you will need to look for one on your own.

There are many ways you can go about finding one on your own. You can search for one on Thumbtack or Yelp. You can also look up nearby homes on airbnb that include accessory dwelling units, and contact the owner to get their contractor’s contact info. Or you can call a home service company and get recommendations for a general contractor.


  • Make sure to look for someone who has extensive experience in building prefab homes, and thoroughly understands the steps it takes to prepare a building site and build the ADU. This is someone you will be working with for a while, so it would be helpful to interview multiple candidates before selecting the one you want to work with.
  • Once you pick a contractor, make sure you get a price estimate.


Can I build the guest house myself?

Yes you can! If you have the specific tools and know-how to correctly and efficiently assemble a prefab home, you can do so with a prefab kit. There are prefab kits available for all kinds of ADUs, whether big, small, contemporary, traditional, etc. So if you do choose to build your module yourself, we can supply detailed plans along with phone and online support. You may also hire one of our techs to assist you on your job site.