Simple Strategies to Meet the IRC’s New Fire-Protection Requirements

Last year, nearly 30 percent of new homes in the U.S. had partial or full basements, according to the Census Bureau’s Survey of Construction. The heaviest concentration continues to be in the Northeast and Midwest, where more than 70 percent of new homes were built atop basements.

The 2012 International Residential Code (IRC) brought significant changes to fire protection requirements for the floor systems above basements. Section R501.3 of the code requires that floor assemblies, not required elsewhere in the code to be fire-resistance rated, must now include a 1/2-inch gypsum wallboard membrane, a 5/8-inch wood structural panel membrane or the equivalent on the underside of the floor framing member.

Often referred to as “membrane protection” requirements, the code also allows several exceptions, including homes with an automatic sprinkler system or floors installed over some crawl spaces.

Many states have already adopted similar language to the 2012 code. They include:
• Pennsylvania – Act 1 of 2011
• Ohio – RCO Section 502.14
• Massachusetts – 8th Edition 780 CMR, Chapter 51, R501.3

Other states that have adopted membrane protection requirements in at least some jurisdictions include Alabama, Colorado, Illinois, Iowa, Kentucky, Maine, North Dakota, Tennessee and West Virginia. Verify existing or pending requirements with your local building official.

The new code will make homes safer, but complying may be problematic and more expensive.

But it doesn’t have to be that way.

Weyerhaeuser has developed an economical and hassle-free solution: Trus Joist® TJI® Joists with Flak Jacket® protection, which feature a proprietary coating that enhances the joists’ fire resistance and enables the floor assembly to meet these new membrane protection requirements.

The Flak Jacket coating, which puffs up when exposed to fire, thereby protecting the engineered wood underneath, meets the 2012 IRC by providing fire endurance equivalent to dimension lumber. This means builders have a straightforward product solution for compliance.

First and foremost, it eliminates the need to install either fire sprinklers or gypsum board in basement ceilings, which saves the builder the added hassle and time. Using Flak Jacket also avoids substituting an uncoated joist with 2×10 dimension lumber, which may not have the same strength properties, length availability, consistency and straightness as an engineered product.

Perhaps most important, installing TJI Joists with Flak Jacket protection allows builders to keep their standard design. They don’t have to change their building practices. The product is lightweight and installs like traditional joists, including using the same hangers and hole charts. Other fire-protection options can be more difficult to handle and install.

As more states continue to adopt fire-protection provisions similar to the 2012 IRC, TJI Joists with Flak Jacket protection provide a cost-effective, less-intrusive solution to compliance, ensuring builders can meet the new provisions without getting burned by the need for extra materials and labor.

For more information, visit or download a Product Overview or Frequently Asked Questions. If you would like additional information or to arrange for a product trial contact our Technical Support team or call us at 888-453-8358.

Glyn Boone
Glyn Boone
Glyn Boone, PE is Senior Engineer for the Weyerhaeuser Engineered Wood Products team. Glyn has over 25 years of experience in wood engineering. He also enjoys woodworking and providing engineering support in developing countries and in situations of disaster relief.