For use as a synthetic underlayment to be applied over the deck prior to installation of the final roof covering. It also is intended as a secondary layer for shedding water after installation of the roof system. Synthetic Guard can be used for wood shake, asphalt or composite shingles. Non-woven surface. Polypropylene 5 × 5 Scrim. Lay lines and cap-nail locations printed on the underlayment. Also includes additional high wind and Florida cap-nail locations.