Building Code Basics

There are two model building codes that form the basis of almost all of the building codes in the United States. The International Residential Code for One- and Two-Family Dwellings (IRC) covers one- and two-family homes of three stories or less, and the International Building Code (IBC) covers all other buildings. Other model codes that are referred to in the IBC and the IRC (and may be relevant to roofing) include the International Fire Code, the International Mechanical Code (covers HVAC systems), and the International Plumbing Code (covers roof drainage). The International Energy Conservation Code (IECC) is of particular importance to low-slope roof design due to its R-value requirements, which affect the amount of insulation that has to be included in roof assemblies. All of these codes are produced by the International Code Council (ICC).

The primary roofing chapter in the IBC is “Chapter 15 – Roof Assemblies and Rooftop Structures“. However, many other parts of the code deal with aspects of roofing; for help finding them see the Quick Roofing Guide to the IBC provided by

The primary roofing chapter in the IRC is “Chapter 9 – Roof Assemblies“. For help finding other parts of the IRC that deal with roofs, see the Quick Roofing Guide to the IRC provided by

Always check with your local building inspector’s office to be certain which version of the building code is in effect in your area. New versions of the IBC and the IRC are produced every 3 years, but they are not adopted or put into effect by local authorities every 3 years. In fact, they are not adopted with any consistency from country to country, state to state, or even city to city. You can usually find out which code is in force by going o the website of your local government, although some of these websites are so hard to navigate that it makes more sense to simply call and speak to someone in the building inspectors’ office. If you do call, in addition to asking which year’s code is in effect, but sure to ask about amendments to the code that might affect your project.

An important thing to be aware of is the fact that the majority of governing authorities that adopt the codes do so with amendments. Local authorities can (and they do) add things, remove things, change the language, and make exceptions to the model code, so it’s not enough to simply know which version of the model code has been adopted.

Even governments at the municipal level in many states have further amended the version of the code adopted (and amended) at the state level.

So what does all of this mean? It’s important that you double-check, read, and understand the relevant sections of your actual local code.

Why should you care? Not all roofing companies perform work that complies with your local building code. The most common way they “cut corners” to save money is by not removing all of the felt on the roof down to the roof deck. Although this may be a code requirement, the result is an installation of a non-compliant roof!

With Affluent Exteriors, you can be confident that all of our work will comply with all local building codes for your property.