IBC vs IRC

By Brian Hansen, Project Manager | August 27, 2020

“The Code”  Everyone has heard that phrase, right?

If you are reading this blog, you are probably interested enough in buildings to know there is a published collection of base codes that govern the construction of all buildings constructed in the United States and other countries around the world. It sets the standards of what is safe and what rules contractors and design professionals should be playing by.

The International Code Council updates their codes every three years and, depending on the local authorities having jurisdiction, the adopted version may vary from state to state. This is because the state-level building authorities do not generally adopt the latest code automatically before getting input from their local contractors and design professionals. Upon receiving feedback, the state officials tend to amend the code as they see fit and while they may adopt a majority of the code right away, they may put a delay on (or possibly never adopt) others.

Here in New Hampshire we adopted the 2015 version of the IBC in September of 2019. Our neighbors in Massachusetts adopted the 2015 version at the start of 2019.

The two most prominent building codes when it comes to constructing buildings, renovations, and/or remodels are the International Building Code and the International Residential Code, each having its own specifics and applications depending on the project.

In short, the International Building Code (IBC) is the code that any building can be constructed from, whether it be commercial, industrial, or multi-family residential (except for one and two-family dwellings, including townhouses, up to three stories in height which must comply with IRC). It addresses health and safety concerns for buildings based on prescriptive (for each individual building element) and performance related requirements (when elements combine to achieve some clear level of building performance). This code is nearly 700+ pages and because of its vast extent of information, these types of buildings generally require a code summary in their design and sometimes often refer to a licensed design professional for input.

Alternatively, the International Residential Code (IRC) is broken down to focus on one and two family homes and town houses up to three stories in height and much easier to follow. Because the information is limited to a certain building type (i.e. residential), this code may seem to have more flexibility when compared to the IBC that has to account for everything from skyscrapers to power plants.

Here at Team Engineering we inspect and design both commercial and residential buildings, so we are very comfortable with all portions of the code.

*When selecting which codes to reference, we remember this simple rule:

IRC:  1-2 family residential buildings (including townhouses), no greater than 3 stories in height

IBC:  Everything else

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