Can I use this on top of my decking boards to stop the water from going to my deck below? Is it water-resistant/proof?

Our 3/8" Pre-Cut Heavy Duty Rubber Rolls are semi-porous and could still potentially allow water to flow to the deck below. To prevent this, we recommend using our Rubber Floor Finish and Sealer to fill in the small pores and use our Seam Sealer glue to fill in the seams around the rolls. This will make our rubber flooring water-tight and prevent any water from flowing to the deck below.