Pergola Metal Inserts . Our special 2′ x 6′ aluminum rafter and 2′ x 8′ aluminum beam inserts allow for spans up to 18’long, giving you a greater shade area with fewer posts! We pride ourselves in making quality american products that are sourced locally and fabricated at our shop in bennet, nebraska. 4K PergoSoleil(TM) Panels 4K Aluminum Aluminum pergola, Backyard from www.pinterest.com Expressly denies any and all warranties of quality whether expressed or implied, including but not limited to warranties as to the fitness for a particular purpose. 4k cantilever can cantilever up to 15ft wide x 12ft extended out with only two posts. Unlike gazebos for instance, pergolas are extremely affordable too.