Appendix Q

Appendix Q: Tiny Houses On A Foundation

First Printing August 2017

Provisions Contained In This Appendix Are Not Mandatory Unless Specifically Referenced In The Adopting Reference

It Is Up To Each Municipality And State To Adopt Appendix Q As A Model Code.

Tiny Houses  On A Foundation: 400 Square Feet Or Less

Written By Janet Thome

Appendix Q Tiny Houses was approved for inclusion to the 2018 International Residential Code ( IRC ) building code to provide regulations and standards for tiny homes on a foundation that is 400 square feet or less

Appendix Q relaxes various requirements in the body of the code as they apply to tiny houses that are 400 square feet or less.
Attention is specifically paid to features such as compact stairs, including handrails and headroom, ladders, reduced ceiling heights in lofts, and guard and emergency escape and rescue opening requirements of lofts.

The International Residential Code is a comprehensive, stand-alone residential code that creates minimum regulations for one-and two-family dwellings of three stories or less.

The IRC brings together all building, plumbing, mechanical, fuel, gas, energy and electrical for provisions for one-and two-family residences.  Appendix Q was adopted to the IRC building code standards through the ICC Code Developement Process.

Jurisdictions may use Appendix Q as a model code to adopt, reference or amend. Builders or even jurisdictions that have not adopted the 2018 IRC or the Appendix, can seek approval ”on a project basis through the alternative materials and designs provision” in the IRC.-David Eisenberg,  co-author of The Strawbale House Book.

The International Code Council (ICC)

Adoptions of the IRC

The International Residential Code (IRC) is in use or adopted in 49 states, the District of Columbia, Guam, Puerto Rico and the U.S. Virgin Islands. Wisconsin is the only state not applicable to IRC building codes. In Alaska the IRC is not adopted statewide. The “Deferred Cities” can adopt additional codes and some jurisdictions adopt the IRC and the IECC.

As a model code, the IRC is intended to be adopted in accordance with the laws and procedures of a governmental jurisdiction. When adopting a model code like the IRC, some jurisdictions amend the code in the process to reflect local practices and laws.


Appendix Q is applicable to tiny homes used as single dwelling units. Tiny homes shall comply with this code unless otherwise stated.

Appendix Q

From The ICC Learning Center 2018 IRC Update

ICC:  ANSI Standard Developer

ICC, the International Code Council, an ANSI Standard Developer ( ASD) is a nonprofit organization that develops and publishes standards related to building safety and fire prevention. Headquartered in Washington, D.C., United States, ICC standards have been codified and enforced in all 50 American states, as well as in various foreign countries. With nearly 340 chapters worldwide, each with many members, ICC building safety standards are used everywhere.

Back Story Of Appendix Q

The International Residential Code has a Big Vision for Tiny Houses February 1st, 2018

Appendix Q Tiny House is  the first set of building standards for dwellings ever incorporated into a model code. The story of how the appendix came to be is a great example of how the Code Council works together with stakeholders and industry professionals to develop model code standards for new and innovative technologies as they emerge.

At the hearing, however, one person had testified in “friendly opposition” to the proposal: Martin Hammer, an architect who had co-authored the IRC’s straw-bale construction appendix. Following the hearing, Hammer received a call from his friend Andrew Morrison of, a builder and educator who had helped Hammer write the appendix. “Andrew asked if I thought we could submit a different proposal,” Hammer recalled.

a Appendix Q: State By State

This is a page is a work in progress, as more states and jurisdictions are added.

List Of Municipality Or State That Has Adopted Appendix Q

Please due your own due diligence. If you see a state or county listed, check with your municipality to clarify that they have the same jurisdiction.

Alaska: In Alaska, the IRC is not adopted statewide. The “Deferred Cities” can adopt additional codes and some jurisdictions adopt the IRC and the IECC.

The IBC, IFC, IMC in Alaska are adopted by administrative rulemaking by the Alaska State Fire Marshal. The adopted code by state agencies are mandatory and falls under state inspection programs unless a local jurisdiction has been delegated by the code program as a “deferred jurisdiction.” When this occurs, the local jurisdiction administers and enforces its local program of the adopted state codes.

State Fire Marshall Of Alaska Richard Boothby

Deferred Jurisdictions

Tiny Homes Juneau

Juneau, Alaska has NOT adopted Appendix Q at this time, however, they are usually it as a Guide for residents to build tiny homes on a foundation. I spoke with a few officials and it will take years for any new code changes. August 1st, 2019.

Tiny Houses on mobile chassis will be allowed in certain situations.

Please contact the CDD for more information at 907 586 0715.

New Edition Of Appendix Q IRC: 2021

Martin Hammer-Architect and the original co-author of the Appendix Q for Tiny Homes has been the primary proponent of the new edition of Appendix Q 2021. Martin Hammer and the following co-proponents have been involved with the editing and public comment process with various degrees of involvement since December 2018.

Co-Proponents Include:

David Eisenberg: Developer Of The Strawbale Appendix Of The 2015 IRC
Chuck Ballard: President Of Pacific West Associates and the Director of Standards Of THIA
Brad Wiseman: CEO and Chairman of THIA
Thom Stanton: COO and President of THIA
Zack Giffin: Co-Host of Tiny House Nation And Board Member Of THIA
Byron Fears: Owner and Builder of SimBlissity Tiny Homes