BuyPlastic it Plastic Sheet 3/4" x 24" x 36" Brown-White-Brown lor re, HDPE Board, High Density Polyethylene Panel 4.6 out of 5 stars 62 1 offer from $150.85 . 1/4" x 24" x 48" Mocha Brown it StarBoard ST HDPE Sheet. It will not warp, rot, or delaminate when exposed to humidity or water.