Appendix BB Tiny Houses Inclusive In 2024 IRC

2018 IRC: Appendix Q Tiny Houses

Appendix Q Tiny Houses was approved for inclusion in the 2018 International Residential Code ( IRC ) building code to provide regulations and standards for tiny houses 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 hand rails 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

Appendix Q Tiny Houses

2021 IRC: Appendix AQ Tiny Houses

The Tiny House Code Name Was Changed To Appendix AQ Tiny Houses In The 2021 IRC

The 2018 IRC included an adoptable appendix for tiny houses. The provisions for tiny houses were based on code change RB168–16 from the 2016 Group B cycle of code development. They have been subsequently revised in the 2021 IRC by code change RB292–19 in the 2019 Group B cycle of code development.

The following are excerpts from the reason statement and the code itself, which provide an overview of the appendix provisions:

Similar to the format for the body of the code, this appendix is structured as follows:

Similar to the format for the body of the code, this appendix is structured as follows:

AQ101: General (Scope)
AQ102: Definitions
AQ103–AQ106 Technical provisions
- AQ103: Ceiling Height
- AQ104: Lofts
- AQ105: Emergency Escape and Rescue Openings
- AQ106: Energy Conservation
There are no standards referenced in the provisions
There are no standards referenced in the provisions

Resource: Building Safety Journal

Appendix AQ Tiny Houses

2024 IRC: Appendix BB Tiny Houses

The 2024 IRC Refers The Tiny House Code As Appendix BB Tiny Houses

Link To 2024 IRC

Appendix BB Tiny Houses.

2027 I-Code Amendments-Adding Provisions For The Wheels

Photo Courtesy: Decathlon Tiny Homes

Appendix Q Tiny House was the initial crowning achievement for the tiny house industry that finally brought the consumers, the building officials, and manufacturers together with the beginning stage for uniformity in the tiny house industry. More than half the nation has adopted either Appendix Q Tiny House or Appendix AQ Tiny Houses which was the 2021 IRC edition which applies to tiny houses on a foundation.

What has been missing is the crucial components on how to construct a tiny house on wheels.

New Standard Being Developed At ASTM

Structure Attachment

Floor Systems

Chassis Systems

Anchoring Systems

Foundations

Enter ASTM- We have been developing a standard that will put the wheels under Appendix AQ Tiny House ( Now referred as Appendix BB Tiny Houses. We are covering the structural attachment, the floor systems, chassis systems, and anchoring and foundation systems. The standard will also include commentary for road regulations, including NHTSA, and DOT requirements. We are aiming to complete the ASTM standard, have it approved and submit the standard as an I-Code amendment to Appendix AQ Tiny House.

Learn More