I'm planning this summer's project for next spring. On top of my park bench I'm building a 2 and half foot by 8 foot warm(electric heater for early spring)/cold storage and was wondering what material would be best to use. We get hail here in the spring and last time I needed to do this was in the 70's (Plexiglass). Got any ideas maybe cheeper or better? just thought I"d bounce it off you guys first. Figuring about 3 foot to 5 foot high.