Playbook on Accessory Dwelling Units and Industrialized Off-Site Construction Published by the International Code Council
Across the country, communities are searching for ways to add housing without overloading infrastructure or driving up development costs. One of the most promising tools is the Accessory Dwelling Unit (ADU), an additional dwelling unit built on the same lot as an existing house. ADUs can serve as affordable rentals, in‑law suites or flexible space for multigenerational living, all while fitting seamlessly into established neighborhoods. At the same time, off-site construction provides opportunities to deploy ADUs with speed and less neighborhood disruptions.
To assist policymakers and building safety officials in leveraging ADUs to address their housing affordability and availability challenges, the International Code Council (ICC) published Unlocking Accessory Dwelling Units and Industrialized Off-Site Construction: A Playbook for Adoption in July 2026. The playbook is designed to be a guide for policy makers on strategies to advance ADU deployment and leverage off-site construction.
Industrialized off-site construction (IC), including volumetric modular and panelized systems, can materially shorten schedules and reduce cost and can help accelerate ADU delivery. However, such solutions must be accompanied by a regulatory ecosystem that provides clear and predictable processes for entitlements, permitting and inspections.
Created to help increase the use of ADUs and IC, this playbook provides insights and details on how to successfully implement these construction practices. Success stories include lessons learned from state and local jurisdictions across the country including Raleigh, North Carolina, Los Angeles, Calif., Massachusetts, Utah, Tennessee and Arizona. The examples highlight how jurisdictions have dealt with issues such as zoning reform, parking, lot sizes, proximity to transit and relation to the main dwelling.
Read the playbook here. Learn more about off-site construction here.
About the Author
The International Code Council is a nonprofit association that provides a wide range of building safety solutions, including product evaluation, accreditation, certification, codification and training. It develops model codes and standards used worldwide to construct safe, sustainable, affordable and resilient structures.
