I'm very impressed with this product! I began using it 2 years ago on cedar siding in the Pac NW. In our wet climate it seems to be doing its job, repelling water, very well. Another plus is that it is a dream to use--once you adapt application to its runny consistency (I find that applying to vertical surfaces is best done with a tank sprayer followed by wiping down with a good sized rag, wet with the stuff. 2 coats are best. Better yet, spray your boards on the flat and roll with a 1/2 inch nap roller. As someone who believed that you had to go with oil-based finishes on exterior applications, I appreciate the easy, water-based clean up and not needing to breath in noxious fumes.