Chapter III - An Introduction to the International Residential Building Code.

Ascertaining which building codes have been adopted in your state is the first step in determining the engineering requirements on your project. As I promised on the web site, I'm going to give you a free PDF download of the building codes for the state you live in.

Download Your Local Building Codes Here

Once the code set is downloaded, the PDF format allows you to easily and quickly search the contents electronically, which is a HUGE time saver! This ability puts all of the code information at your fingertips.

Questions about the code compliance of any part of your design can be efficiently researched with a keyword search under the relevant topics or section.  That doesn’t mean that actually reading and interpreting the code is enjoyable, but at least all the relevant facts and figures can be easily accessed, and the search function helps you avoid tedious thumbing through 700+ pages for the info your looking for. 

The 2006 IRC consists of 700+ pages because it must cover every contingency of design and material; it can be very intimidating, but just remember that the simpler your design is the less of the code will be relevant to your particular project.

If you are unable to locate the building codes for your local jurisdiction via the above link perhaps it’s time to make some personal contacts in your local building departments. You could start by calling on your most local government body that has jurisdiction over the property where you will be building. They will be able to provide you with specific information about which building codes are currently being used as guidelines in the area. You should also ask for any local changes or modifications that have been adopted by that local jurisdiction.

Again, as background for those who want it : As state and local governments around the country came to be more and more involved in the regulation of construction, private organizations were formed to promote comprehensive model building codes. In 1927 the Uniform Building Code was issued by a group of Pacific coast building officials who later became known as the International Conference of Building Officials (ICBO). A similar group called the Southern Building Code Congress International (SBCCI) introduced the Southern Standard Building Code in 1945. Five years later, the Building Officials Conference of America (BOCA), based in Illinois, put out its Basic Building Code.

While the model code groups have helped bring some order, it is estimated that today there are still over 2,000 variations in local codes nationwide.

No wonder it’s confusing!

In 1994 the three bodies mentioned above formed the International Code Council (ICC), and since then they have worked to become a unified national organization with a single set of model codes known as the I-Codes. Codes are still not completely unified however; the National Fire Protection Association (NFPA) still maintains its own model building standards that are used in many states, often in conjunction with the I-Codes.

Model building codes have no legal standing UNTIL an authority having the jurisdiction to do so adopts them.  

Rather than drafting its own building codes, a local authority will usually choose to use the model building codes instead. The model building codes are either adopted (accepted without modifications) or adapted (modified) to a particular jurisdiction and then enforced by the adopting authority. Of course the developers of these model codes urge jurisdictional authorities to refer to their model code in the laws, ordinances, and regulations passed by the jurisdiction. When a model code is referred to, or referenced, in any of these legal instruments that particular model code becomes law in that jurisdiction. This is known as adoption by reference. To make thing even more confusing, it is possible that the jurisdiction may delete, add to, or revise any portion of the model code it is adapting.

Model codes are constantly under revision and there is a 3-5 year update cycle. This means there is new edition of the building code issued every 3-5 years. BUT, the length of time that it takes to review and approve a new code means the currently enforced version of the local code is most often not the most recent edition of the model building code on which the adopted code is based.

The end result of this is that different jurisdictions use different versions of the same code. The number designates the year of the model code – (IBC-2000 was published in 2000).

For example: The City of Phoenix Code incorporates IBC-2006, The Connecticut Code incorporates IBC-2003 and The Nebraska Code incorporates IBC-2000

Keep in mind that the IBC or IRC for 2006 will in large part be the same as IBC or IRC for 2003, with changes, omissions and additions from the previous version noted in the margins of the latest version.

Any discussion of structural engineering concepts for residences must be framed around the standards spelled out in the International Residential Code, which has become the most widely adapted code source in the United States today. We are excluding the IBC (International Building Code) since it includes commercial building and we are concentrating on residential structures.

The engineers at the International Code Council (ICC) have been tasked with considering and accounting for all of the variable construction materials and methods in general use today. In addition, other considerations, such as the local seismic and weather conditions in different regions, are factored in to arrive at a uniform code model that serves as a comprehensive code of building construction adaptable to any region in the nation. It’s the closest thing we have to a national building code and when a community adopts the International Residential Code it becomes, in effect  “the local building code”.

At the local level, other engineers on the building department staff are tasked with verifying load calculations and the stress assumptions that are a required part of every construction plan. It’s their job to verify the calculations on any given project and give it a Yea or Nay. Sometimes this is a relatively simple matter, as in the case of a traditional wood framed home, where a simple check of the floor, ceiling and wall-framing guides.

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