Boise Offers Pre-Approved, Cost-Saving ADU Designs

City partners with local architect to provide no-cost accessory dwelling unit plans, easing housing affordability challenges.

Apr. 11, 2026 at 12:18am

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A brightly colored, high-contrast silkscreen print of a miniature house or architectural model of an accessory dwelling unit, repeated in a tight grid pattern with vibrant neon colors and heavy black outlines, conceptually representing the city's new cost-saving ADU program.Boise's new pre-approved ADU plans aim to make it easier and more affordable for homeowners to add accessory dwelling units, contributing to the city's housing supply.Boise Today

The City of Boise has teamed up with local architect Eamonn Parke to provide eight pre-approved, no-cost accessory dwelling unit (ADU) plans to residents. The goal is to streamline the permitting process and reduce construction costs for those looking to add an affordable housing option on their property. The selection of designs, named after local birds, range from 280 to 695 square feet and aim to be efficient in materials, energy, and costs.

Why it matters

Boise, like many cities, is facing a housing affordability crisis. This new ADU program is the city's attempt to increase the local housing supply in a way that is mindful of these challenges. By providing pre-approved, cost-saving plans, the city hopes to make it easier and more accessible for homeowners to add ADUs, which can contribute to more affordable living options within existing neighborhoods.

The details

The joint effort between the city and Parke's design firm resulted in eight pre-approved ADU plans that range in size from 280 to 695 square feet. The plans are named after local birds found in the Treasure Valley area. The goal is to streamline the permitting process and reduce construction costs for homeowners, as typical ADU plans can cost around $10,000. The pre-approved plans will eliminate the design time and expedite the building permit timeline. While the plans are free, homeowners are still responsible for relevant permits and impact fees. The plans are designed to be efficient in materials, energy, and costs, and can be used in any area of Boise.

  • The city issued a Request for Qualifications (RFQ) for the ADU design program last fall.
  • Between 2019 and 2023, Boise saw an average of 61 ADUs constructed per year.
  • Over the past two years, Boise has seen an average of 106 ADUs constructed annually.

The players

Eamonn Parke

A Boise-based architect and the founder and owner of PARKE Architecture, who led the design of the eight pre-approved ADU plans for the city.

Kayla Duclos

An urban designer with the City of Boise who spearheaded the ADU program.

Maureen Brewer

The director of the City of Boise's Planning and Development Services department.

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What they’re saying

“Although not the entire solution, ADUs have the potential to meaningfully contribute to our city's housing supply in such a way that is particularly mindful of the affordability challenges we are facing together.”

— Maureen Brewer, Director, City of Boise Planning and Development Services

“We feel we are responding to the interest by providing these permit-ready ADU plans.”

— Kayla Duclos, Urban Designer, City of Boise

“The city's attitude toward being able to provide pre-approved plans at no charge to residents of Boise is an effort that I certainly think helps minimize the up-front costs of building an ADU.”

— Eamonn Parke, Architect, PARKE Architecture

What’s next

The Urban Land Institute (ULI) Idaho will host Housing Week from April 13-17, featuring local forums, site tours, networking, and skill-building workshops related to affordable housing options.

The takeaway

Boise's new pre-approved, cost-saving ADU program is a creative approach to increasing the local housing supply and addressing affordability challenges. By providing free, permit-ready plans, the city aims to make it easier and more accessible for homeowners to add ADUs to their properties, contributing to more diverse and affordable living options within existing neighborhoods.