Residential building codes can be a daunting topic for interior designers. They are complex, lengthy, and written in legalese. But interior designers shouldn’t feel apprehensive about having a thorough understanding of the codes pertaining to single-family residences. 

Our first Design Brief will cover basic information about code formatting and application, as well as share the most significant changes that have been made in the last several years.

For a thorough documentation of residential code requirements for specific building features (stairways, fireplaces, electrical outlets, lighting), be sure to check out our Residential Building Codes Handbook.

Building codes are intended to ensure greater safety within the built environment, not to add needless requirements or costs to building construction. In the United States, single-family homes and duplexes are mostly regulated by the International Residential Code(IRC), which is free to access online here. The IRC is in use or adopted in 49 of the 50 states, plus Washington DC, Puerto Rico, and the US Virgin Islands. Wisconsin uses their own hybrid Residential Code, but it is closely based on the IRC. In Canada, codes for housing are covered in Part 9 of the National Building Code of Canada. 

Any building larger than a single-family or duplex residence is regulated by the more expansive International Building Code and other code publications that regulate mechanical, plumbing, and electrical applications. The IRC is largely comprehensive in that it includes mechanical, electrical, and other considerations for single-family homes and duplexes. However, other code documents and standards are referenced within the text.

Most building codes—including the IRC—are updated every three years to encompass emerging building construction strategies. The current version of the IRC was published in the Spring of 2024, with upcoming versions scheduled for 2027, 2030, 2033, and so on. However, each individual municipality (city or township) can choose which version they adopt and when, provided they are utilizing codes published within the previous ten years. Check with the municipality’s building department website (where the project home is located) to verify which version is being enforced. 

Several notable changes have been made to the IRC in the last few years, which are summarized in this article.