Outdoor rugs made from 100% polypropylene — like Sand Mine outdoor rugs — will not mildew because polypropylene is a synthetic fiber that does not absorb water, which is the primary condition mildew requires to grow.
Mildew develops when moisture gets trapped in a material and can't escape. Polypropylene's flatweave construction has an open structure that lets water drain through rather than soaking in, so the rug dries quickly after rain or hosing down. Natural-fiber outdoor rugs — jute, sisal, cotton blends — absorb moisture and are significantly more susceptible to mildew, especially in humid climates or shaded setups where drying is slow.
- Sand Mine outdoor rugs are made from 100% virgin polypropylene, a non-absorbent synthetic fiber.
- Polypropylene flatweave construction allows water to pass through rather than pool on the surface.
- The Sand Mine 9x18 ft and 6x9 Lattice carry a waterproof designation; most other sizes are water-resistant.
- Natural-fiber rugs (jute, sisal, cotton) absorb moisture and are not mildew-resistant for outdoor use.
- Sand Mine rugs clean with a garden hose rinse and air dry without scrubbing or mildew-prevention treatments.