Ice and water shield is a type of self-adhering waterproof membrane commonly used under slate roofing to provide extra protection against water infiltration, especially in vulnerable areas like eaves, valleys, and around chimneys or skylights. Slate roofs, known for their durability and natural resistance to water, can still face issues when ice dams form during winter. Ice dams occur when melting snow refreezes at the roof's edges, causing water to back up under the slate tiles and potentially leak into the structure below. Using ice and water shield beneath the slate acts as a barrier that sticks directly to the roof deck, preventing water from seeping through cracks or fissures in the slate itself or from compromised flashing.
Homeowners or DIY enthusiasts can perform a simple check by inspecting the key areas prone to ice dams for any signs of water stains inside the attic after winter storms or heavy snow melt. Look for loose or missing slate tiles and inspect flashing around roof features for visible damage. While applying ice and water shield requires some roofing knowledge to ensure proper adhesion and avoiding trapping moisture, taking photos of your roof’s underlayment during replacement can help document proper use for warranty purposes. When calling a roofing contractor, ask if they use ice and water shield rated for slate and if their installation includes proper overlap and sealing details to prevent ice dams. Also, inquire whether their work complies with manufacturer guidelines to maintain warranties and durability.