ADU Design Tips: Maximizing Space, Flexibility, and Value

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Building an Accessory Dwelling Unit (ADU) can be a significant investment, but it has the potential to enhance your property’s value, provide passive income, and offer flexible living arrangements. Whether you are considering constructing an ADU for rental income, housing family members in a multigenerational living space, or want the extra space to house guests or use for additional living space, thoughtful design is key. Here are a few important ADU design tips to consider to build an ADU that maximizes space, value, and adaptability for future use.

Why Build an ADU?

There are many benefits to building an ADU in Boise and other areas of southwestern Idaho. The decision to build an ADU is often driven by these benefits. Before we continue with our top ADU design tips, let’s take a quick look at some of the top benefits of building an ADU: 

  • Increasing Property Value: Adding an ADU can significantly boost the overall value of your home. According to the National Association of Realtors, homes with an ADU are priced 35% higher on average than homes without an ADU.
  • Generating Passive Income: Many homeowners choose to build an ADU to rent it out, either as a short-term rental or as a long-term rental. This can provide a steady stream of additional income, particularly in cities like Boise where there is an ongoing housing shortage. See the City of Boise’s housing needs analysis for more information.
  • Housing for Relatives: With multigenerational living on the rise and an increasingly competitive housing market, many Idaho residents are turning to ADUs to house aging parents or grown children. Using an ADU provides an independent living space while keeping family close. For more specific information on multigenerational living, see our top considerations for building a multigenerational home.
  • Additional Living Space: Even if it isn’t used as a rental or residence for relatives, an ADU adds livable space to your primary residence and can be used as a guest house for visitors or other purposes like a home office workout room.

No matter the reason you have for building an ADU there are several ADU design tips and elements to consider that will help you create a more functional space, no matter the purpose.

Top ADU Design Tips From An Idaho ADU Builder

ADU Design Tip #1: Determine Eligibility

Regardless of where your property is located, there are local zoning regulations that you need to consider as the first step of your design process. 

ADU building regulations in southwestern Idaho can include things like: 

  • A minimum lot size
  • Setback regulations
  • Distance between primary residence or buildings on neighboring lots
  • Property access
  • Parking space requirements

Your local city planning department is an excellent resource for determining the specific regulations that apply to your property. Working with a local home builder that is experienced in building ADUs in Meridian, Boise, and other municipalities in Treasure Valley can provide insight to help you determine what size and type of ADU is possible to build on your land. 

A local ADU builder can also be an invaluable resource as you navigate the Boise ADU approval process, or the building permit approval for an ADU in another local jurisdiction.

Utilities

As part of your ADU design and eligibility considerations, keep in mind that utility hookups can also factor into your ADU design. For example, utility hookups can impact where you need to build your ADU on your land so that you can take advantage of existing hookups without having to pay more for utility setup. Utility connections are always part of our preconstruction considerations for any custom home build, whether it’s an ADU or custom residence. 

Also consider that having separate utility meters can be beneficial if the ADU is rented out, as it allows tenants to be responsible for their utility bills.

One utility that can often be overlooked is your septic system. If your property has a septic system, don’t forget to ensure that your current system can handle the additional use when you add an ADU to your property. 

ADU Design Tip #2: Build A Flexible Use ADU

One of the most important ADU design considerations is flexibility. The use of your ADU may evolve over time, whether it’s transitioning from rental property to a living space for a family member, or being sold to a future homeowner with different needs. Designing an ADU that is adaptable to different functions ensures that it remains a valuable asset, no matter how its use changes.

When designing your ADU, keep in mind the different uses of an ADU and make sure that the features you select don’t unnecessarily limit the use of the space. All of the ADU design tips we’ve included here apply no matter how you plan to use your ADU.

ADU Design Tip #3: Maximize The Interior Space

ADUs are most often smaller than the main house on the property and often this parameter is part of local ADU regulations. For example, in Boise ADU requirements are that an ADU can’t be larger than 900 square feet or the total floor area of the primary building, whichever is smaller (Source: City of Boise).  In Nampa, Idaho ADU regulations don’t allow for any ADUs over 500 square feet (Source: City of Nampa). With limits on the square footage of an ADU maximizing space is critical. 

No matter what size ADU you end up building, these space-saving ADU design tips will help you create a space that is both functional and comfortable. 

Key Space-Saving Tips for ADUs:

  • Smart Furniture Choices: Use furniture that doubles as storage, such as storage ottomans, under-bed storage, or a storage bench in the entryway. Low-profile furniture like platform beds can make rooms feel larger. You can also consider foldable or multi-functional furniture, like futons, wall beds, or foldable tables and desks to maximize floor space for items that are not always in use.
  • Compact Appliances: Space-saving appliances such as stackable washer and dryer combinations or tankless water heaters, which take up less space than traditional water heaters, can free up valuable space for other items like additional storage or usable square footage in your ADU.
  • Use Pocket Doors: Pocket doors save floor space by eliminating the need for a door swing. In our Piedmont ADU floor plan, for example, a pocket door separates the kitchen from the pantry, which helps optimize space in the main living area.
Low profile furniture in a bedroom to represent one of the ADU design tips to maximize the interior space
Use low profile furniture to make a small space appear larger.

ADU Design Tip #4: Include Built In Storage

In any custom home design incorporating adequate storage space is essential to a functional home. In a smaller space like an ADU, storage space becomes even more important in creating a comfortable living space. This is true no matter how you choose to use your ADU. Include more storage space with these ADU design tips.

  • Utilize Vertical Space: Make use of all the space in your ADU by building up. Install shelving or cabinets that reach all the way to the ceiling to create more space for storage while also making your space feel bigger by drawing the eyes up. You can use this vertical space throughout your ADU, in an entryway, laundry area, and the kitchen.
  • Add A Kitchen Pantry: The kitchen is one of the areas where storage is most important. Consider including a kitchen pantry when designing your ADU for this added space. All of our ADU floor plans make use of a kitchen pantry to ensure adequate storage in this important area.
  • Don’t Forget Closets:  Certain ADU floor plans leave out closets in an effort to increase the usable floor space; however, a closet in the entryway or closets in any bedroom help keep the usable floor space more organized. For long-term residents closet storage is important, so think twice before leaving these out to maintain the flexibility of how you use your ADU.
Pathway Builders Shop House Floorplan With Attached ADU Pantry
A kitchen pantry adds necessary storage space in a small ADU kitchen.

ADU Design Tip #5: Add Outdoor Space and Access Considerations

Maximizing the outdoor space around your ADU is just as important as the indoor design. Adding a porch, deck, or patio can significantly increase the living area, providing a more expansive feel to the entire unit. 

While our Piedmont ADU floor plan incorporates an outdoor patio space as a standard inclusion. Patio space can be added to any of our ADU floor plans to extend the livable area of the unit without increasing the square footage. 

Creating usable outdoor living spaces is one of the custom homebuilding trends we have been seeing for several years now applying to all custom home builds beyond ADUs. Adding this outdoor living space is a relatively low-cost way to add space to any ADU while remaining within local square footage regulations.

ADU Design Tip #6: Think About Privacy

For any ADU, privacy of the separate dwelling is one of the main benefits so incorporating privacy into your ADU design is a key consideration no matter how you plan to use it. 

Consider these items in your ADU design to incorporate privacy features that will make the ADU more comfortable for anyone using it: 

  • Location & Layout: The location of the ADU on your property is a factor in privacy. Space is one tool to use to separate the ADU from the primary residence. However, when space is limited, the layout of the ADU can create greater privacy.
  • Window Placement: When there is more space between dwelling units, window placement is less important. But in a compact space, thinking about window placement and using it strategically can go a long way in creating a space that enhances privacy for the primary dwelling and the ADU.
  • Consider Access: The entryway, including the exterior doors and the walkways to those doors, is another area to incorporate privacy. A separate entry for the ADU is often a zoning requirement, but using a separate walkway or entry into the yard for the ADU can add an additional element of privacy that will be appreciated by those coming and going from the ADU. A separate driveway or parking area is another feature that can make the ADU feel more private.
  • Outdoor Space: When outdoor space is included, consider the placement of this space to separate from the outdoor space of the primary residence. This can be achieved if outdoor spaces are separated by the ADU itself or with the use of privacy screens or fencing.
  • Landscaping: Strategic use of landscaping like trees, shrubs, or other plants, can also create a more private feel. These elements are often easier to adapt to different ADU uses and can even be removed if needed.

ADU Design Tip #7: Smart Interior Design

In addition to functional additions that maximize space, there are several interior design elements that can be incorporated into your ADU design to make the space feel more spacious and comfortable.

  • Natural Light: Maximize natural light by strategically placing windows and, if possible, incorporating skylights. Ample natural light can make a space more inviting and the brighter light can make the space feel larger.
  • Light Fixtures: Beyond use of natural light, be sure to use ample artificial lighting in your ADU design. This is important for making sure the space is usable and flexible. Consider incorporating dimmable light fixtures to allow for multiple uses and comfort. Using recessed lighting can give the illusion of a taller space. 
  • Color: Light colors on walls, ceilings, and trim can make spaces feel larger and more open. Similarly, using the same color for ceilings, walls, window trim, molding, and baseboards will also help the space feel larger. 
Pathway Builders Shop House Floorplan Kitchen Full View
Ample natural light in the kitchen, main room of our Pinewood floor plan.

ADU Design Tip #8: Include Accessible Features 

If your ADU is intended for older relatives or as a long-term housing option, consider incorporating accessible features. This also makes your space more flexible for future residents and can be more appealing for potential renters. 

Important accessibility features include wider doorways, zero-entry showers, grab bars and a seat in the shower, adjustable shelves, and adjustable cabinets or countertops. A single-level ADU with no stairs and minimal steps is ideal for aging-in-place ADU design.

Budgeting for an ADU

Finally, budgeting for your ADU project is crucial. Costs can vary widely depending on the size, design, and local building regulations. It’s a good idea to get a quote early in the design process so you have a clear understanding of the potential expenses. 

If you’re building an ADU in Boise or southwestern Idaho, you can use our instant quote tool to get a cost for any of our ADU floor plans based on the location of your property and any upgrade options you want to include. For a more custom ADU design, you can contact us for an initial consultation to discuss your project.

Conclusion

Designing an ADU requires thoughtful consideration of space, flexibility, and future use. By focusing on these top ADU design tips you can create an ADU that adds significant value to your property and adapts to a variety of uses. Keep local building regulations in mind, and always work with an experienced ADU builder to ensure the process goes smoothly from start to finish. If you are looking for an experienced ADU builder in the Boise area, we’d love to talk to you. You can contact us for a free consultation. If you are looking for inspiration for an ADU, you can view our previous projects or learn more about ADU trends.