Will these provide a solid water-proof surface if applied on a 2nd story redwood deck that has a patio underneath? We want that lower patio to be protected from rain. If not these, would a different product of your work?

Our Flagstone Rubber Pavers are semi-permeable and would not be a waterproof surface over another patio. The only way to make these rubber pavers waterproof would be to add a sealer to the flooring. Our Rubber Floor Finish and Sealer would work, but you would need to reapply it quite often to ensure no water gets through the tiles. Also, we would recommend sealing the space between the tiles with our Seam Sealer glue.