The surface must be sound and thoroughly cleaned before Vetoseal XW770 is applied. All loose particles, old mortar, laitance, dirt, paint, etc., must be removed by brushing with a stiff/wire brush or other suitable means. Fungi or Algae should be scoured away using hypochlorite type bleach or proprietary fungicidal solution and then washed with water. Remove all traces of oil and greases with an industrial-grade chemical degreaser or another suitable degreasing agent.