System 9 System 9 System 9   System 9 Post & Beam Extension Simple clean design and attractively detailed interior woodwork -- A traditional wood post and beam extension. Choose from finely detailed oak or pine interior and bronze, white or sandtone maintenance-free aluminum exterior. Slow growth Canadian woods provide stability and strength. Aluminum tracks drain away water. The traditional post and beam model can easily be customized to accommodate different roof slopes, special shapes or any unique design you require. Our exclusive reverse mortise and tenon joinery actually gets stronger the more you put weight on the joint. Fine quality detailing in the woodwork and spacious 36" wide glass sections make System 9 a superb choice. 100% of ALL Four Seasons Products Use Tempered Safety Glass! Our glass is four to six times stronger than ordinary window glass and much safeter too. In fact, our tempered safety glass has smooth rounded edges and meets ANSI 297.1-1984 codes for safety. If broken it would shatter into harmless rounded pellets.