5. Why two base compositions? What are the application differences between the solvent and water based products?

A short-form answer to this problem does not exist. Concerning product differences, with respect to carrier bases (solvent vs. water), the first notable difference is price. Solvent based products are certainly more expensive than the other water based products. Concerning differences in application, water based products may have a tendency to ‘blush’ or ‘cloud’ if misapplied to a dark brick substrate, that is why Combocrete hesitates to recommend the application of water based materials to brick or brick veneer substrates. While, on the other hand, Microcrete and Stain-Blok products water-based products perform quite well on these substrates. One very important comment concerning the difference between water and solvent based products …. you must understand that all clear liquid waterproofing products are designed to resist the penetration of water into the substrate. Application of a second coat of water based product, therefore, would be impossible since the first coat would prohibit, or repel, the second water based coat from penetrating the first coat. The attempted second coat would simply dry on the surface and eventually turn into a chalky residue.