An ADU (Accessory Dwelling Unit) is an independent living space on a single-family property, complete with kitchen, bathroom & private entrance. Types include detached units, garage conversions & basement apartments. Ideal for rental income or family housing.

American Building Group, Portland, ME

About American Building Group

What Is an Accessory Dwelling Unit (ADU)?

An Accessory Dwelling Unit (ADU) is a fully independent, smaller residential structure built on the same property as an existing single-family home. Unlike a simple addition or extra room, an ADU functions as a complete living space on its own — equipped with its own kitchen, bathroom, living area, private entrance, and utilities.

American Building Group works with homeowners looking to add this type of structure to their property, guiding them through the process from planning to completion.

Common Types of ADUs

ADUs can take several different forms depending on the property layout and the homeowner's goals. American Building Group handles a range of ADU construction types, including:

  1. Detached ADUs — standalone backyard cottages or granny flats built separately from the main home
  2. Attached ADUs — units connected directly to the primary residence
  3. Garage conversions — converting an existing garage into a livable, code-compliant dwelling unit
  4. Basement or lower-level apartments — transforming underutilized space into an independent unit

Each of these options serves different needs and comes with its own set of structural and permitting considerations. As an experienced ADU contractor, American Building Group is familiar with local building codes and zoning regulations that apply to each project type.

How ADUs Are Used

Homeowners pursue ADU construction for a variety of practical reasons. Some of the most common uses include housing family members such as aging parents or adult children, creating a in-law suite or Casita for extended family, or generating rental income through a long-term or short-term tenant.

An ADU can also increase the overall value of a property, making it a practical investment for homeowners thinking about the long-term potential of their real estate. Whether the goal is a backyard cottage, a JADU (Junior Accessory Dwelling Unit), or a full detached ADU, the structure adds usable square footage without requiring a separate lot purchase.

American Building Group approaches each project with attention to the specific needs of the homeowner and the requirements of the site. Their role as an ADU builder involves coordinating the design, permitting, and construction phases to keep the project on track and within regulatory guidelines.

For homeowners considering adding an accessory dwelling unit to their property, working with a qualified accessory dwelling unit builder like American Building Group can help ensure the project is completed properly and in compliance with applicable local standards.

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Monday 7:00AM - 5:00PM
Tuesday 7:00AM - 5:00PM
Wednesday 7:00AM - 5:00PM
Thursday 7:00AM - 5:00PM
Friday 7:00AM - 5:00PM
Saturday 9:00AM - 4:00PM
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