Cover your bottoms… covering of I-joist floor joist in unfinished spaces such as unfinished basements.

There is a new requirement in the 2012 IRC about floor joists that requires them to be covered. This is mainly aimed at the engineered/manufactured I-floor joists.

2012 IRC- R501.3 Fire protection of floors.

Floor assemblies, not required elsewhere in this code to be fire-resistance rated, shall be provided with a 1/2-inch (12.7 mm) gypsum wallboard membrane, 5/8-inch (16 mm) wood structural panel membrane, or equivalent on the underside of the floor framing member.

I found this to interesting and significant. When talking with a friend who is a firefighter one of the greatest concerns for firefighters in newer construction was with engineered materials such as I-joists and trusses. The reason is that under a fire scenario these materials do not have the same ability to remain structurally strong for as long as dimensional lumber. Creating a greater risk for a firefighter to fall through during a response.

It is now required that 1/2” sheetrock (gypsum board) or other approved membranes will need to be installed on the underside of floor assemblies of structures using manufactured joist in construction or dimensional wood 2x8 or smaller.

This change is for the protection of Fire personnel during a response to a structure fire.

Here is a link that will help bring the reasoning into light-

It’s not lightweight construction. It's what happens when lightweight construction meets fire.

“If you think it's expensive to hire a professional to do the job, wait until you hire an amateur.”

Red Adair

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