Applying Penetration Primer for Roofs
Use a brush to scrub the Bostik Penetration Primer well into the roof surface. Apply only a thin coat and make sure there is no pooling. Let it dry completely before overcoating. Bostik Penetration Primer for Roofs should be applied using disposable brushes whenever possible. It can also be sprayed thinly and evenly. Allow drying thoroughly before overcoating.
Apply generously to saturate the surface with fibre cement or old roofing felts. Priming should extend at least 75mm beyond the area to be waterproofed.