Behind the Strength of Pella’s Proprietary Fiberglass
Pella's proprietary fiberglass material is the strongest material for windows and patio doors, engineered for lasting durability.*
*Disclosure: Pella’s proprietary fiberglass material has displayed superior strength over wood, vinyl, aluminum, wood/plastic composites, and other fiberglass materials used by leading national brands in tensile and 3-point bend tests performed in accordance with ASTM D638 and D790 testing standards.