With the Spa Pad, installation is extraordinarily simple: Four hi-tech polyethylene pads replace the need for a concrete spa foundation. Each pad is 50″ x 50″ x 3″, available in gray, lightweight (31 lbs. each), extremely chemically resistant and UV stable. Four pads (two sets) needed for one spa. A 10′ x 10′ (3 m x 3 m) area must be level and cleared of debris for proper installation.