There are alternatives to wood based plywood... 
Comparison of different products (pdf).

Technical specifications (pdf).

Durapoly 4' x 8' Sheets
Durapoly looks more recycled than the others and has a rougher surface, but is still good for jobs where appearance is not critical. Natural or Gray color only. This is paintable, but may not hold the paint with traffic. 4 x 8 sheets only - yes you can order 1 sheet , but minimum freight charges apply(usually $200 in freight) Usually, it is more economical to order at least 5 sheets We can do special runs(sizes and colors), but need 600 sheets to alter from the program above.
Thickness (MM) Price/sheet Weight Pallet Qty 1/4 nat 6  $     92.70 40 60 1/4 grey 6  $    102.00 40 60 3/8 nat 9  $     97.20 55 50 3/8 grey 9  $   106.90 55 50 1/2 nat 12  $   131.10 77 40 1/2 grey 12  $   144.20 77 40 5/8 nat 16  $   165.00 97 30 5/8 grey 16  $   181.50 97 30 3/4 nat 18  $   185.40 108 25 3/4 grey 18  $   203.90 108 25 1" nat 25  $   332.10 150 20 1" grey 25  $   365.30 150 20 1.25" nat 32  $   382.00 193 16 1.25" grey 32  $   420.20 193 16 1.5" nat 38  $   455.40 229 14 1.5" grey 38  $   501.10 229 14