By Kevin Klotz
We frequently asked about using our moisture mitigating primer on old, moist concrete and new “green” concrete. Believe it or not, those two situations are similar, bringing into play both primer choice and cure time.
In nearly any concrete coating job where moisture vapor pressure is a potential issue, we recommend using our WearCOAT 1080 Moisture Mitigating primer. It’s a versatile, 100-percent solids epoxy primer that excels at containing moisture vapor pressure to protect the resinous flooring products to be applied above it.
WearCOAT 1080 is also a great choice in new construction, as it allows green concrete to be coated seven to 10 days after the new concrete is poured which is much quicker than waiting the customary 28 days for water in the new concrete to gas off. This two- to three-week time savings allows the construction process to be sped up considerably – something general contractors and building owners appreciate.
However, here’s an important catch: WearCOAT 1080 can’t do both! If you need the primer to reduce moisture pressure from below the slab on green concrete, you have to wait the full 28 days for the concrete to cure. This is true of any moisture mitigating primer.
Green concrete that has only cured for 10 days still has moisture in it. When you apply a coating to that concrete, it doesn’t create the same chemical and mechanical bond that it does with fully cured concrete. So, if additional moisture vapor pressure from ground water is present, the primer can’t be counted on to hold that down.
If you know that a proper moisture barrier was put down beneath the concrete the pour AND you don’t anticipate additional moisture issues from below the slab, then using WearCOAT 1080 after 7-10 days is a good choice. If you think there may be moisture issues – for example, where the new slab sits on a high water table – or if you’re just not sure, it’s best to wait the full 28 days after the pour before priming.
At CFI, we are always happy to help contractors out of tough situations. If you need help with a coating job – even if it’s not our product – click to reach Customer Service or call +1-215-723-0919.