Azek pioneered co-extrusion and a trend setter in modern synthetic decking. Azek uses a cellular PVC core under it’s proprietary polymer outer layer. The Azek polymer is the second hardest and thickest capstock we have tested and one of the only brand that allows pressure washing for maintenance. Azek has enjoyed a excellent track record in the field and is the most reliable board you can install. Strengths of Azek decking include: ease of installation, low maintenance, cool to the touch on hot days, light weight. Azek can be dimensionally stable eliminating the need for gapping at the butt joints if it is face fastened. The Arbor collection colors rate high on our abrasion testing. When used with hidden fasteners systems gaps at the butt joints and borders can be difficult to manage due to changes in length with temperature changes.