International Residential Code (IRC) vs Local Codes

[escanlan (Emmanuel Scanlan, TREC# 7593)]

@Pat_Flemming

Emmanuel Scanlan, thanks for taking the time to post your detailed reply.

I see that the IRC does not nullify any provisions of local codes, and manufacturer’s specifications take precedence over the contents of the IRC.

The manufacturer’s requirements take precedence over the codes if they are following one of the many other standards in use, or if their materials/systems have been engineered using acceptable engineering practices, or if they have their materials/systems tested/reviewed by the ICC Evaluation Services Division (http://www.icc-es.org/) or another accepted test and evaluation organization.

So, this seems to be relevant in situations were local codes are more strict/stringent than the IRC. What about the opposite? What if the IRC mentions a clause that a local code doesn’t?

Long, long ago in a land far, far away … The IRC at one time did specify that any deviations from the building codes must meet the intent of the codes and be as strict or more strict than the basic requirements in the codes. Unfortunately the International Code Council (ICC) who are the keepers of the codes buckled under pressure and took that language out of the codes to make builders, local officials, etc., happy.

As for the codes stating a requirement that is not covered in a local building code amendments unless the local building department has specified otherwise, and they have officially adopted the codes, then the codes are to be followed. However you do need to keep in mind that the local Building Official can render a different interpretation that they have not officially written in an amendment. This can be done on a case by case basis or even through their own internal memos.

Back to my example: the IRC no longer recognizes moisture-resistant, paper-faced drywall (“green board”) as a suitable tile backing material in wet areas such as tub and shower surrounds. However, there is no such language in my local/national building code.

Do I have a case again my builder that is using green board in my shower stalls. Can I reference the IRC?

The IRC sections you are looking for are R702.3.7 and R702.4. These section numbers are from the latest 2015 IRC code cycle. If you are using a different (older) code cycle they should be in that same area of the codes.

Answers in blue above. Please do come back and let us know how it worked out with your builder.