R400 Rubber Application for Conventional Gravel Roof

  1. Inspect the entire roof surface. Excess gravel should be removed and all blisters should be cut open and allowed to dry. Remove all debris, trash, etc.
  2. Apply the Cement Catalyst/Portland Cement mixture to the entire roof surface. The mixture must be made liquid enough to flow through the gravel. Apply the slurry until the gravel is covered or until a “level” surface is obtained. The slurry system can be installed with a soft pushbroom or squeegee. The slurry should be applied in two coats, allowing the first coat to dry before applying the second.
  3. After the slurry has cured for 3 days, apply the Pro Bond 200 to the entire surface. This sealer usually dries in less than 1 hour.
  4. Apply the R400 Rubber to the entire surface in 2 coats of 11 mils each. Two complete coats should have a thickness of 22 dry mils.
  5. Anywhere where water ponds or lays , Polyester Membrane must be used. First put a coat of R400 down, then immediatly roll a section of fabric out, then immediatly roll another coat of R400 over the fabric, then allow to dry. After drying you need to apply 2 additional coats of R400 Rubber over the fabric, or until no fiber strands are visible.
  6. No top coat is required with R400 Rubber. Due to the non chalking surface, there will be some dirt pickup.

Installation Notes

  • On a gravel roof surface, one 5 gallon bucket of R400 Rubber will cover 200 square feet of gravel roof, which will result in 22 dry mils of waterproofing.
  • On a gravel roof surface using Polyester Membrane, one 5 gallon bucket of R400 Rubber will cover 90-100 square feet of gravel roof. It is recommended that where the ponding water lays, R400 Rubber must be embedded with the Polyester Membrane.
  • If spraying the R400 Rubber, it must be chased with a roller

Helpful Videos