Accessory dwelling units (ADUs) might feel like a new trend, but they were once far more common in American neighborhoods. Small secondary homes might have been called granny flats or carriage houses, and were often used to house extended family members. They were an easy way to create additional living space on the property, allowing families to live together or host long-term guests or renters. Modern zoning regulations limited or banned these units in a lot of communities, but recently, cities are updating their rules to allow them once again. It’s led to a boom in ADU building in a lot of communities.
ADUs can be a practical solution for addressing the lack of affordable housing. They can create space for multigenerational living, as a short-term rental, or a home for a live-in caregiver.
If you’ve been considering adding an ADU to your property, one of the first decisions you’ll need to make is whether an attached or detached ADU makes the most sense. Let’s explore attached vs detached ADUs and which is better suited to your property and long-term plans.
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What Is an ADU and Why More Homeowners Are Building Them
An accessory dwelling unit is a smaller, self-contained living space located on the same property as a primary home. It typically includes its own entrance, kitchen area, bathroom, and sleeping space. While the structure may be smaller than the main house, it functions as an independent living environment.
Homeowners pursue ADUs for many reasons. Some want to create a comfortable space for aging parents while maintaining proximity and independence. Others want a place for adult children who are transitioning between stages of life. In many cases, the goal is simply to provide a flexible space that can serve different needs over time.
For families planning for multigenerational living, ADUs offer a practical solution that balances privacy and connection. The additional unit allows family members to live nearby without sharing the same interior spaces.
Attached ADUs: Expanding the Existing Home
Attached ADUs integrate with the existing structure of the home. In some cases, they are created by converting existing spaces such as garages or basements. In other situations, the unit is built as a new addition that connects directly to the house.
Benefits of Attached ADUs
Attached ADUs often make efficient use of the home’s existing infrastructure. Plumbing, electrical systems, and heating equipment may already be nearby, which can simplify construction planning. The connected layout can also make it easier for family members to move between spaces when needed.
Because the structure ties into the main home, attached ADUs may involve fewer site changes on the property. For homeowners with limited yard space, this can be an appealing solution.
Considerations for Attached ADUs
While attached units provide convenience, they may offer less separation between households. Sound transfer and shared walls can affect privacy if the spaces are not carefully planned. Thoughtful layout design, insulation, and separate entrances can help address these concerns.
Detached ADUs: Creating a Separate Living Space
Detached ADUs function as independent buildings located on the same property as the primary home. They are sometimes described as backyard cottages, carriage houses, or small guest houses.
Benefits of Detached ADUs
Detached units offer a higher level of independence. Because the living space sits in a separate structure, occupants often experience greater privacy and separation from the main home. This arrangement works well for households that want proximity without daily overlap.
Detached ADUs also allow more flexibility in design. Since the structure stands on its own, the layout can be planned specifically for the occupant rather than adapting to the constraints of the main house.
Considerations for Detached ADUs
Building a separate structure usually requires additional site planning. Utility connections must extend to the new building, and the project may involve grading, foundations, and access pathways. These factors can increase the overall scope of construction compared to an attached unit.
Lot size and local zoning regulations also influence whether a detached ADU is feasible. Some properties may have more room to accommodate a small standalone building than others.
Designing ADUs to Support Multigenerational Living
Looking for a way to create space for multiple generations of family to live under one roof…or at least, on one property? An ADU can be ideal for this. But multigenerational living works best when everyone has the right balance of independence and connection. You can achieve this by:
- Creating separate entrances to maintain privacy.
- Building layouts that include living areas, a kitchen, and bathrooms in each unit.
- Thoughtfully placing windows for natural light without sacrificing privacy.
- Using insulation and layout design to create sound separation.
- Designing wider doorways, step-free entries, and practical bathroom layouts for aging-in-place concerns.
Work with a builder experienced in designing ADUs and aging-in-place spaces. They can help you consider all these factors and design an ADU that accounts for the needs of your household now as well as the needs you may have in the future.
Attached vs Detached ADUs: Which is Right For Your Home?
Trying to decide if an attached or detached ADU is better for your property? It may depend on:
- Lot size and property layout. The size and configuration of your property may dictate what’s actually possible. Larger yards may have the space for a detached unit.
- Privacy needs. If you want a lot of privacy, detached is the way to go. IF you need to be closer to keep an eye on loved ones, then attached may be better.
- Budget constraints. Attached units are typically more cost-effective because they can share the infrastructure of the primary house. Detached ADUs may need more site preparation and utility connections.
The option you choose can also depend on the long-term plans you have for your property. An ADU designed for a parent today might be useful as a guest house or rental studio later on. Planning for long-term adaptability may give you more insight into which option is better for your property.
Choosing the Right ADU Solution for Your Ann Arbor Property
Every property and household brings different priorities to the planning process. Some homeowners want a living space that stays closely connected to the main home, while others prefer a separate structure that offers greater independence.
Thinking through how the space will be used now and in the future can help clarify which direction makes sense. An experienced ADU builder in Ann Arbor can evaluate the property, discuss the goals for the space, and help shape a design that works for both the home and the people who will live there.
For many homeowners, an ADU opens the door to new possibilities. It can create a comfortable place for family members, support multigenerational living, or simply add flexible living space that evolves with the household over time. MBK Constructors works with Ann Arbor homeowners to turn those ideas into thoughtful, well‑designed additions. If you are considering an attached or detached ADU for your property, a consultation with the MBK team is a great place to start.
