What is an alternative to ice and water shield in tile roofs?

The use of two plies of underlayment bonded with interply adhesive serves as an effective alternative to ice and water shield in tile roofs. This method provides superior protection against moisture infiltration, which is a critical concern in roofing applications, particularly in areas prone to ice dams and severe weather conditions.

By utilizing two layers of underlayment, you create a more robust barrier against water. The interply adhesive seals the two layers together, reducing the likelihood of water penetrating through seams or potential weak points. This is crucial for tile roofs, which can have gaps and spaces that make them more susceptible to leaks compared to other roofing materials.

In contrast, single-layer methods like tar paper may not offer the same level of protection, as having just one layer increases vulnerability. Foam insulation, while beneficial in terms of energy efficiency, does not specifically address water infiltration issues. Metal flashing is used for waterproofing along joints and edges but does not serve as a full underlayment solution across the roof surface. Therefore, the choice of two plies of underlayment with interply adhesive stands out as the most suitable alternative to ice and water shield for tile roofs.