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What is an ADU?

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Recently, many homeowners and property managers have opted to address high housing costs by adding a second living space to their property. These units, called ADUs, can house everyone from aging relatives to long-term tenants.

There are advantages and drawbacks to adding an ADU to your property, and the practice isn’t allowed everywhere. In this article, we’ll explore everything you need to know about accessory dwelling units and whether they’re right for you.

What is an ADU Unit?

An ADU (Accessory Dwelling Unit) is a secondary housing unit built on the same lot as a primary residence. Sometimes called rental units, in-law suites, or backyard cottages, these independent living spaces have gained popularity due to housing shortages, affordability concerns, and changing family dynamics. Some ADU units even provide additional living space with their own kitchen, bathroom, and entrance.

An ADU is a smart solution for homeowners looking to expand their living space, generate rental income, or provide housing for family members. When built properly, they can contribute to sustainable housing solutions while enhancing property values. While there are challenges, the benefits of accessory dwelling units make them an attractive investment.

Who Can Live in an ADU?

An accessory dwelling unit is a versatile housing solution that accommodates various occupants. Some common residents include:

  • Family Members: Aging parents, adult children, or extended family can live in ADUs while maintaining independence.
  • Tenants: Homeowners often rent out rental units like an ADU unit for passive income.
  • Caregivers: A live-in nurse or caregiver can reside in an accessory dwelling unit to assist family members with special needs.
  • Guests: Some homeowners use ADUs as guest houses for visitors or short-term rentals.
Inspector talking with homeowners inside their kitchen.

The legality of building an accessory dwelling unit on your property depends on local zoning ordinances, building codes, and state regulations, which can vary significantly by location. Some areas encourage rental unit development to address housing shortages, offering streamlined approval processes, relaxed parking requirements, and reduced fees. Others impose strict limitations on size, height, occupancy, and whether the property owner must reside on-site.

Homeowners interested in adding an ADU should consult their local building department before proceeding. Officials can clarify zoning restrictions, permit requirements, and design standards to ensure compliance. Sometimes, they may also provide information on financial incentives or other ways to simplify the process. Failing to verify regulations beforehand could result in costly fines, legal disputes, or needing to modify or remove the unit after construction.

Pros and Cons of Building an ADU

Adding an accessory dwelling unit to your property can be a valuable investment, but it also comes with challenges. Weigh these pros and cons carefully to help determine whether building an ADU is the right decision for your property and financial situation:

Pros

  • Additional Income: Renting out an ADU unit generates passive income, helping homeowners offset mortgage payments.
  • Increased Property Value: Well-designed accessory dwelling units can enhance property value and resale potential.
  • Flexible Housing Options: Whether for family, tenants, or personal use, ADUs provide long-term flexibility.
  • Eco-Friendly Living: Many modern accessory dwelling units incorporate energy-efficient designs, reducing their carbon footprint.
  • Affordable Housing: ADUs help address the housing crisis by providing smaller, more affordable rental units.
Finished basement with recess lighting

Cons

  • Upfront Costs: Constructing an ADU unit requires a significant investment, from permitting to materials and labor.
  • Zoning and Regulations: Some areas have strict zoning laws and permit requirements for ADUs.
  • Limited Space: Since an accessory dwelling unit is smaller than a primary home, space constraints can be a challenge.
  • Property Tax Increases: Adding an ADU may raise property taxes due to increased home value.
  • Maintenance Responsibilities: Homeowners must manage repairs and tenant-related issues if renting out their ADU unit.

Things to Keep in Mind When Building an ADU

Building an ADU unit requires careful planning, especially regarding foundation and waterproofing. A durable foundation ensures stability, while proper waterproofing protects against moisture damage and structural issues. Key considerations include:

  • Foundation Type: Depending on the lot, an accessory dwelling unit may need regular slab, crawl space, or basement foundation repairs and upkeep.
  • Drainage Systems: Poor drainage can lead to water damage. Installing sump pumps and French drains helps divert water away from the ADU unit.
  • Waterproofing Materials: High-quality sealants, vapor barriers, and insulation extend the lifespan of accessory dwelling units.
  • Building Codes Compliance: Ensuring compliance with local building codes prevents future legal and structural issues.
A person in a blue shirt expertly installs a PVC pipe onto a blue and red sump pump on gravel, ensuring optimal drainage for effective basement waterproofing.

By investing in a solid foundation and effective waterproofing, homeowners can maximize the longevity and efficiency of their ADUs, ensuring they remain safe, comfortable, and resilient for years to come.

Go with Groundworks for Expert Waterproofing & Foundation Repair

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Adding an ADU to your property can be a great way to make the most of your available space, but it’s crucial to make sure the new development is safe and stable for its residents. As long as you plan carefully and in accordance with local regulations, you can enjoy the benefits of an accessory dwelling unit.

Whether you’re concerned about the drainage capacity of your new rental unit or your existing home needs a foundational boost, trust the experts at Groundworks to provide lasting support. Contact our team today to get started with a free inspection.

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Conor Battles

Conor Battles

Content Writer

Conor is a content writer and SEO coordinator for Groundworks with years of media experience across a variety of channels, including in home services and interior design. He’s passionate about using digital storytelling to help homeowners envision the ideal space for their unique needs. While based in Northeast Ohio, Conor was born and raised in New England and enjoys the outdoors, local music, and old movies.