Four years ago we built a new patio and used concrete pavers and polymeric sand in the joints. The polymeric sand has been a nightmare. My father-in-law and I built the whole thing and installed the sand as our final step. About 75% of it never set up. We thought maybe it was because we never used a Vibraplate to get the sand settled into the joints properly -- otherwise we followed all the directions perfectly. The place we bought the pavers from (who had recommended the sand) said they would come out and redo that part of the project for us. So two professionals came out, shop-vacced all the sand out and even used the Vibraplate. This time I would say 50% of it never set up, despite them following the directions perfectly and we didn't get any rain on it too soon, etc. We left it and have struggled with it since then -- lots of moss growing because it's wet all the time (it's on the north side of our house and gets a lot of shade), and just looks horrible.

I just went through a few linear feet of it to remove all the wet stuff, but left the cured stuff. This is what it looks like. As you can see, there are some spots where it's set up perfectly, but a lot where it didn't that I have since dug out. (Ignore that the pavers need to be cleaned -- I live on a gravel road so that is a constant battle of dust.)

Are there any other products out there that work better than polymeric sand? Or has it improved in the last four years? Any foolproof brands of polymeric sand? I've thought about just putting in pea gravel but I think that will just be a mess too when it rains. I don't mind doing the dirty work of removing the sand and starting over, if I know it's something that will work.