Shockwave drainage boards channel water away from foundations. In below-grade applications, its crush-resistant memory protects walls and waterproofing membranes during backfill. Made of recycled closed-cell foam, the board is environmentally friendly and comes in 3x4-foot sheets for less waste during installation. Its R-value is not affected by underground moisture. Mar-flex Waterproofing and Basement Products. 800-498-1411.