Accessory Dwelling Units (ADUs) are self-contained living spaces located on the same property as a primary residence, either attached to or separate from the main home. These fully equipped units feature a kitchen, bathroom, and bedroom, offering independent living for occupants. Despite their proximity to the main house, ADUs maintain privacy and autonomy for both the primary and secondary residences.
ADUs come in a variety of shapes and forms, and they are sometimes referred to by different names such as additional dwelling units, in-law suites, or backyard cottages. Whether you're looking for extra living space for family members, a rental unit, or a home office, an ADU can offer flexible, affordable options without the need to buy a new property.
Massachusetts recently enacted the Affordable Homes Act, its most ambitious legislation to address the state’s pressing housing cost challenges. This law introduces key initiatives, including permitting accessory dwelling units (ADUs) under 900 square feet by right on single-family lots.
Read more about this legislation HERE.
Types of ADUs: Internal vs. External
When it comes to ADUs, they generally fall into two main categories: internal and external. Both types have their benefits, depending on your property’s layout and your specific needs.
1. Internal ADUs
An internal ADU is built within the existing structure of the home. It’s essentially a converted space inside the main house, offering all the benefits of a standalone unit but without the need for additional construction outside. These are often created by repurposing basements, attics, garages, or even large spare rooms into fully functional living spaces.
Advantages:
Cost-Effective: Since you're utilizing existing space, internal ADUs tend to be less expensive to build than external ones.
Space Efficiency: These units are ideal for maximizing underused or wasted space within your home.
No Need for Additional Foundation: Since you're working within the house's existing footprint, there’s no need to lay a new foundation or worry about zoning restrictions related to exterior construction.
Common Internal ADU Examples:
Basement Conversion: Transforming a basement into a fully functional living space, complete with kitchen, bathroom, and living area.
Garage Conversion: Turning a detached or attached garage into a small apartment or studio.
Attic Remodel: Converting an attic into a livable unit with its own access, kitchen, and bathroom.
Home Addition: A living space added onto the main house, often as an extension of the existing structure, creating a new living unit with its own separate entrance.
2. External ADUs
External ADUs are standalone structures built on the same property as the primary residence. These can be anything from a small cottage in the backyard to a separate building built over the garage or a tiny home. External ADUs offer more privacy and independence compared to internal units, as they are fully separated from the main home.
Advantages:
Privacy: External ADUs offer more privacy for both the residents of the ADU and the main home, making them ideal for rental units or multi-generational living.
Increased Property Value: Adding an external unit can increase your property value, especially if it’s designed with a separate entrance and amenities.
Flexibility: These units can be designed to serve various purposes – from guest houses to home offices or rental units.
Common External ADU Examples:
Backyard Cottage: A small, separate structure in the backyard with its own kitchen, bathroom, and living space.
Above-Garage Units: A separate living space built above a garage, often designed as an apartment or studio.
Detached Tiny Homes: A fully independent small home placed in the backyard or on the side of the property.
Why Build an ADU?
There are many reasons why homeowners consider adding an ADU to their property. Some of the most common include:
Extra Space for Family or Guests: An ADU is a great way to offer independent living for family members or provide a comfortable guest suite.
Rental Income: ADUs can be rented out to generate extra income, helping to offset mortgage payments or supplement household income.
Home Office or Studio: With more people working from home, an ADU can be a perfect solution for creating a private office or studio space.
Aging in Place: For older adults, an ADU can provide a more independent and comfortable living arrangement, either for themselves or as housing for caregivers.
Conclusion
Whether you're considering an internal or external ADU, both offer unique advantages to homeowners looking to expand their living space. They can be a versatile and cost-effective way to enhance your property while providing more room for your needs. From rental opportunities to accommodating aging relatives or creating a private workspace, an ADU can be a valuable addition to any home. If you're interested in exploring the potential of adding an ADU to your property, consulting with an architect can help ensure the project is designed to meet your specific requirements and local building regulations.