The Xypex treatment that will be successful in waterproofing of CMU (concrete block) depends largely on the quality of the CMU. In some regions of the world the CMU is very “tight” where as in other regions it is really very porous. It is my best understanding that the relative tightness of the block has mostly to do with the nature of the sand in the region in which the block is being made.
The outcome of this is that in some areas where the CMU is quite tight, CMU water holding structures are waterproofed easily with a two coat applications of Xypex Concentrate followed by Xypex Modified or just 2 coats of Xypex Concentrate. However, in areas with less dense CMU a two coat system of Xypex Concentrate followed by Xypex Megamix I is required.
Certainly Xypex can and is used for waterproofing of block based Koi ponds. I would recommend contacting your local Xypex dealer or local Xypex Technical Representative (this
information can be found on the Xypex web site) and ask their advice on how best
Posted on 31 Mar 2014