In many parts of the country, wildfires have become a growing annual concern. Just as the Gulf and Atlantic coasts have fortified houses for hurricanes, homeowners and builders in areas of high fire danger are paying closer attention to exterior materials that help reduce the chances flame spread. Decking should be no exception.
Here’s what suppliers and buyers need to know.
Understanding Fire Resistance
Evaluating building materials for fire resistance first requires knowledge around common terms.
Ignition Resistance
The state of California, and surrounding states that have adopted its standards, have an “ignition resistant” designation for building materials that resist catching fire or burning easily and that may slow the spread of flames. Ignition-resistant decking is less likely to catch fire compared to traditional and composite decking materials.
Flame Spread Index
Flame spread ratings are based on the measure of how quickly and how far flames travel across the surface of a material. This indicates a material’s resistance to fire and its potential to contribute to the spread of flames. Flame spread ratings range across an index of 0 to 200. A Class A Flame Spread Rating, the best rating, has a range of 0 to 25; Class A indicates superior fire resistance, meaning the material is highly effective at inhibiting flame spread. Class B has a range of 26 to 75, and Class C has a range of 76-200.
Ratings for flame spread are incorporated into the model building codes as published by the International Code Council, including the International Building Code (IBC), the International Residential Code (IRC), and the International Fire Code (IFC), to name a few.
WUI (Wildland Urban Interface) Compliance
Wildland Urban Interface refers to areas where houses and areas prone to wildfires meet. These areas are at high risk of wildfires, so building codes have specific requirements for materials like decking. Here’s what makes a deck WUI-compliant in the state of California (and other neighboring areas):
• Resists flame spread: WUI-approved decking has a flame spread rating from an A to a C. An A rating means it has the lowest rate of flame spread and burns more slowly.
• Resists embers: Wildfires often shower sparks and embers, which can ignite materials. WUI-compliant decking resists catching fire due to flying embers.
Some jurisdictions designated as WUI areas, especially in California, Colorado, and Nevada, require that certain building products meet the Class A Flame Spread Index rating.
However, it’s important to note that just because a product is WUI-compliant does not mean it has a Class A Flame Spread Index rating — and vice versa. In order for a material to meet the standards for a Class A Flame Spread Rating and WUI compliance, it would need to undergo specific testing for each classification.
TimberTech® Decking for Fire Zones
PVC decking is made from 100% polymer (PVC) material and typically no wood fibers, making it a good fire-resistant decking choice for fire-prone areas. But not all types of PVC decking are created equal. It requires specific, advanced engineering to create PVC decking that reduces flame spread enough to earn a Class A flame spread rating.
Two of the TimberTech® proprietary Advanced PVC decking collections—Vintage and Landmark—combine authentic wood looks with unparalleled performance while also offering an Ignition Resistant designation, Class A Flame Spread Rating, and WUI-compliance.
In addition, TimberTech® offers four collections—Harvest, Porch, Reserve (fire-resistant SKUs only), and Premier (square-shouldered boards only)—that are WUI-compliant and carry a Class B Flame Spread Rating.
Protect the Framing
For an added layer of protection, TimberTech® now offers TimberTech® Aluminum Framing. Not only does the aluminum framing offer rot-resistance, it won’t burn like wood and won’t rust like steel. TimberTech® Aluminum Framing comes with a Class A Flame Spread Rating, the highest available, meaning that it is unlikely to contribute to aggressive flame spread. TimberTech® Aluminum Framing also offers long spans, lies straight and flat, and is lightweight and easy to cut. (Learn more here.)
Beautiful, Reliable Decking
Specifying decking with high fire resistance and WUI-compliance provides peace of mind that homeowners can enjoy outdoor spaces while knowing they’ve taken proactive steps to help protect their deck against fire hazards. The TimberTech® Vintage and Landmark collections deliver authentic hardwood looks in eye-catching colors, ensuring you can get the look you love with the performance to match.
This article was repurposed from the TimberTech blog. Connect with your Weyerhaeuser rep to learn about the built-in innovation of the complete TimberTech® portfolio.
