Does CRC use Ice and Watershield, and what is that? Ice and Watershield is the solution for winning the battle against water penetration in your roof's most vulnerable places. WinterGuard®, our favorite brand of Ice and Water Shield, is a composite material of asphalt polymers, formed into a rolled sheet. The asphalt makes it vapor-tight, and the polymers make the asphalt elastic and sticky. This protective barrier is able to stretch and seal around nails driven through it. Placing WinterGuard® at the eaves, in valleys, and around chimneys and other obstacles on your roof, provides your first line of defense.