Tyvek DrainWrap is engineered with vertical grooves on the material’s non-woven surface, providing bulk water drainage by channeling it to the outside. The housewrap resists air infiltration and water intrusion and allows moisture vapor to diffuse through the sheet. DrainWrap is recommended for use behind fiber cement and primed wood siding, and can also be used in conjunction with foam-board and other flat substrates. 800.448.9835. www.tyvek.com. Circle 165.