Practically nonabsorbent, HDPE won't swell when exposed to moisture. It is denser and more rigid than LDPE, plus it's more chemical resistant.

Also known as starboard, these sheets and bars won’t degrade when exposed to salt water, humidity, and UV light.

Also known as pipe-grade HDPE, these sheets are about four times more impact resistant than standard HDPE and hold up outdoors, and in wet environments.