Concrete sealer cost per square footJun 14, 2016 · Negative - Side Waterproofing is not a Primary Seal There has been some recent discussion and inquires on the Tremco PQ 200. PQ 200 is Tremco’s crystalline waterproofing product and it should not be considered as a primary waterproofing membrane in below grade applications. Noeep.phppiwiizdCostar 2k Flex is a flexible two component waterproofing membrane with tough-elastic properties suitable for both positive and negative side waterproofing of interior and exterior concrete and masonry surfaces. Application Areas. Indoor and Outdoor; Horizontal and vertical application