EPOXY BASED MOISTURE VAPOR REDUCTION SYSTEMS
Two part solvent less Epoxy Coatings based on Bis A or Bis F epoxy resin (EEW190 type) and a modified cycloaliphatic amine of the 1,3 BAC type (Epoxycure 423) are an excellent starting point for these systems.
Hydrostatic pressure in concrete floors can be caused by, in the case of newly poured concrete, the cement hydration reaction.
Water vapor transmission (WVT) in existing or old concrete may originate from temperature and humidity differences inside the concrete and room space above.
Wet conditions below ground level can cause a hydrostatic head. Forcing water vapor up through the pores of the concrete and cause blistering to a coating.
A two-pack (Epoxy Resin\Amine) solvent-free Epoxy is, by itself, a very good vapor barrier coating (.4 grams MVT) then can be further reduced by the additional of the Platey Mineral Fillers. These products arrange in a platey pattern with each other in the epoxy coating and provide an additional moisture barrier and reduce the MVT rate below .2. These products are used at low levels with very good effect.
EC 422A and EC 423 offer the formulator range of cure times, low application viscosities and through cure times permitting a good return to service window. The cure profile of EC 423 in particular, assures a water barrier in high humidity conditions of summer applications. These are gained at the sacrifice of work life but this can be handled by smaller mixes on the job site.