Considering building an ADU in Boise?

Accessory Dwelling Units (ADUs) have become a popular solution for expanding living space within existing residential properties. Particularly in Boise, where housing demands continue to grow, ADUs provide a versatile option for homeowners. Whether you’re considering building an ADU to accommodate family members, generate rental income, or increase your property’s value, understanding the intricacies of ADU construction is crucial. This guide covers everything you need to know about building an ADU in Boise, from planning to execution.

1. Understanding ADUs: What Are They?

An Accessory Dwelling Unit (ADU) is a secondary housing unit on a single residential lot. Commonly referred to as granny flats, backyard cottages, or in-law units, ADUs can be detached from the main house or attached as a built-on extension. They typically include a kitchen, a bathroom, and a separate entrance.

Key Features:

  • Detached or Attached: ADUs can be a separate structure or part of the main home.
  • Complete Facilities: They are self-contained with their own living, cooking, and sleeping areas.

2. Benefits of Building an ADU in Boise

ADUs offer several benefits that make them an attractive option for many property owners in Boise:

  • Increased Property Value: ADUs can significantly increase the market value of your property by adding usable living space.
  • Rental Income: They can provide a steady source of income if rented out.
  • Flexibility: ADUs can serve as guest houses, home offices, or long-term housing solutions for family members, offering privacy and independence.

3. Zoning Laws and Regulations in Boise

Before embarking on an ADU project, it’s important to understand the local zoning laws and regulations. Boise has specific requirements regarding the size, location, and design of ADUs:

  • Size Restrictions: Typically, ADUs cannot exceed a certain percentage of the lot size.
  • Height Limits: There are height restrictions to ensure that ADUs do not overshadow neighboring properties.
  • Design Compatibility: ADUs must often match the architectural style of the main house to maintain aesthetic consistency in the neighborhood.

4. Planning and Designing Your ADU

Effective planning and design are crucial for a successful ADU project. Consider the following steps:

  • Assess Your Needs: Determine what you want to achieve with your ADU. Is it for rental income, a personal office, or family use?
  • Hire Professionals: Engage with architects and builders who specialize in ADUs. They can help navigate through design constraints and legal compliances.
  • Design Considerations: Optimize the layout for functionality and comfort. Think about natural light, storage solutions, and privacy.

5. Construction and Building Materials

Choosing the right materials and construction techniques can impact the cost, durability, and appearance of your ADU:

  • Sustainable Materials: Opt for eco-friendly materials that improve energy efficiency and reduce environmental impact.
  • Quality Construction: Ensure that the construction is carried out by licensed professionals to guarantee safety and compliance with building codes.

6. Cost and Budgeting

The cost of building an ADU can vary widely based on size, materials, and labor:

  • Budget Planning: Create a detailed budget that includes all possible expenses from design to construction and finishing touches.
  • Cost-Saving Tips: Consider cost-effective solutions like prefabricated units or repurposing existing structures like garages.

7. Navigating Permits and Legalities

Obtaining the necessary permits is a critical step in the ADU construction process:

  • Building Permits: Ensure all required permits are obtained from local authorities to avoid legal issues.
  • Inspections: Regular inspections by authorities ensure the construction adheres to the approved plans and building codes.


Building an ADU in Boise can be a rewarding project that enhances your property’s value and functionality. By understanding local regulations, engaging with experienced professionals, and carefully planning and budgeting, you can ensure the success of your ADU construction. For more detailed information and expert assistance, visit our ADU Construction page.

Freimark Construction

Considering building an ADU in Boise?

This comprehensive guide should serve as a valuable resource for those considering or currently planning an ADU project in Boise, helping to streamline the process and maximize the potential benefits of their investment. Contact us if you’re ready to start your ADU construction, or have any questions about Boise ADU’s!

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