What is an Accessory Dwelling Unit (ADU)?

Accessory dwelling units (ADUs) are rapidly gaining popularity across the United States, especially in areas facing housing shortages. As more New Hampshire homeowners seek ways to add value, flexibility, and affordability to their properties, ADUs are becoming an increasingly attractive solution.

Whether the goal is to provide additional living space, generate rental income, or create a more sustainable housing option, ADUs deserve to be part of the conversation.

What is an ADU?

An ADU is a secondary housing unit located on the same property as a single-family home. These units are smaller than the main residence but come fully equipped with a kitchen, bathroom, bedroom, and living space.

An ADU can be a home addition attached to the main house, such as a basement apartment or garage conversion, or a separate, detached structure like a tiny house or “granny flat” in the backyard.

The Growing Popularity of ADUs

The rise of accessory dwelling units can be seen across the country, with California, Oregon, and Washington leading the way. In New Hampshire, ADUs are gaining traction for several reasons:

• The housing shortage: The U.S. faces a major housing shortage, and New Hampshire is no exception. ADUs provide a smart response to housing challenges by offering affordable rental options and increasing the overall housing supply without large-scale developments.
• Increased flexibility for homeowners: ADUs allow homeowners to accommodate guests more comfortably, provide independent living spaces for aging family members, or generate additional income by renting out the unit.
• Smaller environmental footprint: ADUs are typically more eco-friendly than building new, full-size homes. They often utilize existing infrastructure, require fewer materials, and consume less energy once built.

ADU Requirements, Laws, and Permits in New Hampshire

State law allows all single-family homeowners to build an ADU on their property under certain conditions. However, restrictions and requirements apply:

• Size and occupancy: Some towns in New Hampshire require ADUs to be 750 square feet or less with no more than two bedrooms. The property owner must also occupy either the main house or the ADU.
• Parking requirements: Many areas require that an ADU have its own dedicated parking space, which can be a challenge depending on the property’s layout.
• Permit application process: To build an ADU, homeowners must apply for a building permit and obtain zoning approval. The process varies by location, so check with local authorities for specific regulations.

Foremost Builders remains an active member of the New Hampshire Home Builders Association (NHHBA). The NHHBA was instrumental in getting a new state law passed that allowed for more ADUs.

The law was a response to builders’ challenges and state housing needs; it increased the housing supply, made better use of existing infrastructure, and provided more affordable housing.

Challenges & Considerations

While ADUs offer many benefits, they come with challenges that homeowners should keep in mind:

• Zoning restrictions: Some neighborhoods have strict zoning laws that limit the size, type, or location of ADUs. Research local regulations thoroughly before launching your project.
• Community opposition: Despite their benefits, not everyone loves ADUs. Neighbors or community groups may express concern about increased density, traffic, or neighborhood character changes.
• Costs associated with building an ADU: The project cost may be higher than anticipated once you account for design, permits, construction, and site modifications.

Consider the following before moving forward with an ADU project:

• Budgeting and financing options: Building an ADU is a financial commitment. A home equity loan or mortgage refinance may be necessary to make the project feasible.
• Impact on property taxes and resale value: Adding an ADU may increase your property taxes, but it also raises your home’s resale value by offering additional living space or rental income potential.
• Hiring a professional: Bringing a professional design/build firm onboard streamlines the process. With decades of experience in New Hampshire and a reputation for quality and transparency, Foremost Builders can help you navigate the ADU planning, permitting, and construction process.

Choose Foremost Builders for Your ADU Project

Constructing an ADU could be smart for New Hampshire homeowners looking to address modern housing challenges. At Foremost Builders, we pride ourselves on being the only design/build firm in the Lake Sunapee and Upper Valley areas with the expertise to guide you every step of the way.

If you’re thinking about adding an ADU to your property, let’s talk. We’d love to help you explore what it will take to realize your vision.