Tyvek's CommercialWrap D helps meet challenges of heavy rainfall, windblown water, snow and humidity, while preventing water intrusion and accumulation which can lean to mold and water damage. CommercialWrap D controls air leakage, which can impact the efficiency of HVAC systems. It also prevents water infiltration, which can reduce the effectiveness of insulation, and cause wood damage and corrosion. It also allows water vapor to escape when moisture does get in, letting wall systems dry, helping prevent mold, and protecting and improving building air quality.