There’s a lot to consider when picking out the right ADU: size, materials, backyard placement, and access. Learn how to plan to make the most of this investment.

Are you thinking about building an accessory dwelling unit (ADU) in your backyard? This is a great option if you have grown children that are going to college or need to save money to purchase their own home one day. It’s also perfect for elderly parents that want their own space but still need to be close enough for you to make sure their needs are met. Or maybe your house is just too small and that extra space would be perfect for a home office. Whatever your reasons are for building a granny unit, here are some factors to consider to make sure that you’re getting exactly what you want.

Access to the ADU

What are you going to use your ADU for and how do you want to access it? For example, if you’re using it as a home office, you may want to install a side gate and path to the unit so clients won’t have to walk through your home to get to your office. Or perhaps you’re building your tiny home as a rental unit. You certainly want to have a separate entrance to get to it and you might want to consider the ease of moving in and out of the structure if the residents are providing their own furniture. Plush landscaping or an arbor may restrict this task.

On the other hand, you may have small children or live in a busy city and you need a bit more security for your property. You may want to add a camera and a security lock to your gate. Or maybe your ADU is an art or yoga studio and you just need a path from the house to the ADU’s door. This could also impact the position of the ADU on your property. 


Think about the size and shape of your property and where the unit should be located. If you have a renter, the windows from both buildings shouldn’t be facing each other. Awkward! 

However, there are several ways to define “public” versus “private” spaces. Bushes, trees, and privacy screens can not only block views but can also outline your renter’s space and your personal space. Let’s say your renter wants to plant a garden or put out their own homey decor. Having designated zones that you clearly spell out before they move in can help to avoid messy disagreements later on. 

What about privacy with existing neighbors? Some cities may have setback laws for coastal zoning programs or utility easements. However, the State of California ADU Handbook states that, “a setback of no more than four feet from the side and rear lot lines shall be required for an attached or detached ADU.” 


Like with any big purchase, know your budget and do your research before you start the project. This is going to help you with the decision making process about what size and materials you can have for your ADU. 

If you’re thinking about making your tiny home into a rental unit, find out how much similar rentals are going for. Better yet, contact your real estate agent or property manager to get a realistic estimate. This will help you to determine your budget and decide if this is a sound financial decision for you. Your ADU company should also have floor plans and samples to show you in your budget range so you’ll get a fair idea of what to expect.


Check with your city or HomeOwners Association (if applicable) to see if there are any guidelines that you have to follow. For example, an HOA may have restrictions such as size, color, height, and materials that you need to abide by. Historic districts and larger cities may also have a checklist that needs to be followed.

Also, the unit should coordinate with your existing home which will help if you decide to move. Not only will it be aesthetically pleasing, but it will appeal to the buyers of your home who are attracted to style of the main structure. 


For most granny units, they can be hooked up to the main home’s electricity and plumbing. However, if you live on acreage and want a home a fair distance away, you may need to consider solar panels, an eco toilet, and alternative plumbing. This could add up to a lot very quickly. Also, style and quality of materials can increase your costs, so determine what you have to have (maybe you want to splurge on the kitchen appliances and cut back on the landscaping) and ask about the cost differences between materials (wood vs. laminate flooring, quality of cabinetry, etc.).


Determining the purpose of your prefab home is definitely going to dictate the layout of your unit. If you just want a home office, a smaller unit may work well for you. If you have a single college student, then a one bedroom backyard home may be perfect. If you have a larger lot, maybe a two bedroom home would work great and a renter could use one room to sleep in and another as an office. Think about all the possible functions this living space could have to maximize its living – and earning – potential. 

Also, think long term and resale value. You may just want a home office now, but what about five or ten years down the road? It would be easier and more cost effective to add a kitchen and bathroom now and in a few years, your 22 year old son might rent it while saving for a house or your parents could use it in their retirement years. What makes the best sense for your family in the present AND the future?

There’s a lot to consider when you’re thinking about building an ADU. However, one choice is easy: pick ADU Warehouse! We’ll help you weigh all of your options and guide you through this journey. We understand that it’s an investment, so our goal is to help you every step of the way!

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