Shingle Grip is a non-hazardous additive that is designed to increase the foam generated with your bleach cleaning solutions. Thicker foam will aid in extending the contact time of 12.5% Sodium Hypochlorite "bleach" to cling onto roofs, walls, etc. Shingle Grip also Contains an extra penetrating surfactant to accelerate a more effective and advanced bleach cleaning. Directions: We recommend adding 1 qrt (32 ounces) per 55 gallons of 12.5% bleach solution. Shingle Grip produces extra thick foam when using 2 qrts.