Along time ago I coated my basement with a coating that came in a 5 gal bucket, it was a dry powder and you mixed it with water and painted it on. I think the name of that type was called **** tight, and I haven't had any water issues from water seeping through the blocks. I remember it was hard to apply and took quite a long to time to put on. The last that we put on was also powder but I believe it was a different name and wasn't quite as good. If I ever have to do anymore coating of blocks I am going to try to find something already mixed and a little easier to apply, even if costs more. We had a study built for my wife and a basement under it for my mule and someone told my wife to use driveway sealer filler on the outside of the blocks to seal them. The drive way sealer filler went on easy enough but I haven't had it back filled yet so I don't know how well it will work to prevent dampness. I know one thing though the blocks looked nice if having a black foundation under your building would be okay. I mentioned painting one of my buildings completely with the driveway sealer but the wife don't think much of that idea. Has any of you used the driveway sealer that way, and is it possible to put some kind of tint in it to change the color a little?