If you’re looking for a backyard build that combines all the nature-inspired beauty of traditional wood with the leading materials science of composite decking, look no further than TimberTech. An additional benefit: Our The TimberTech AZEK® Vintage Collection® boasts a Class A Flame Spread Rating. Because your deck should fight moisture and flame spread alike.
What Is ‘Flame Spread Rating’?
Flame spread rating is calculated by the distance a flame travels across a material, divided by the amount of time it takes to travel that distance.
Testing for flame spread rating involves burning materials under controlled conditions and measuring the speed and extent of flame spread.
Materials with Class A Flame Spread Rating are those that hit a certain threshold indicating less flame spread and/or slower time to travel as compared to other materials below Class A.
Where Does Class A Flame Spread Rating Come From?
The International Code Council (ICC) and affiliate group, the International Building Code (IBC), develop standards related to building construction. These standards take into account fire-safety related factors like:
- Fire protection systems (sprinkler system requirements and design)
- Materials used in construction
- Elevators and escalators
- Means of egress (or leaving a structure)
The IBC recognizes the benchmark from a third organization, the American Society for Testing and Materials (ASTM): Standard Test Method for Surface Burning Characteristics of Building Materials, or ASTM E84.
Flame Spread results range on an index from Class A (the best) to lower classes. Lower classes indicate that more distance was covered by the flame in the same amount of time, or that less time was needed for the flame to travel the same distance, as compared to a Class A material.
What to Know
FLAME SPREAD RATING INDEX =
A numerical reference that measures how fast and far a flame spreads during a 10-minute test.
CLASS A =
Flame Spread Index of 25 or less; the best possible rating, awarded to fire-retardant building products, like concrete.
What Is WUI Compliance?
WUI stands for “Wildlife Urban Interface” and was adopted by the California Building Commission a decade and a half ago. WUI designates areas that are within or adjacent to communities deemed “at-risk” for wildfires. WUI-compliant building products, therefore, mean those below a certain threshold for flame spread.
Some jurisdictions designated as Wildland Urban Interface (WUI) areas, especially in California, Colorado, and Nevada, actually require that decking products meet the Class A Flame spread rating.
One of those products? The TimberTech AZEK® Vintage Collection®.
The Vintage Collection

Leading Tech
The most advanced synthetic material technology, without the use of wood particles in the core or cap.

Superior Performance
Backed by industry-leading warranties: A 50-Year Limited Fade & Stain Warranty and Lifetime Limited Product Warranty.

Fully Synthetic Material
Engineered to not only protect against invasion from moisture, insects, and other harmful agents but to curb flame spread.
Why Does TimberTech Offer Class A Flame Spread-Rated Decking?
Put simply? Because Better Tech Means Better Deck. We combine sustainable manufacturing processes with innovative materials science so that your composite deck boards can keep their shape, hue, and beauty — even when faced with harsh conditions.
WUI-Compliant TimberTech Products

We know feeling great about the performance of your home is important. With WUI-compliant composite decking, you can feel good about your outdoor living space, and about your role in protecting the planet.
Ready to see and feel better tech for yourself?