This month’s feature in FLOORS is entitled “Below the surface – it’s what’s beneath that counts” so I found it fitting to comment on the importance of moisture content in flooring.

Testing concrete screeds for excess moisture is a common epoxy flooring requirement, where epoxy (impermeable membrane) coatings are to be installed over them. While several standard moisture test methods are available, no single test shows everything that should be considered in choosing the timing of when an epoxy coating can be applied.

Fortunately, experience and some simple tests can help determine if the moisture content in a screed is within an acceptable range for the application of epoxy coatings.

The simplest way of testing is to take several sheets of clear plastic about 150mm x 150mm and seal around the edges with insulation tape. Leave these sheets overnight and inspect the next day. If the screed is darker under the plastic and there are water droplets under the plastic sheeting, this represents moisture still present in the screed.

The rule of thumb in my opinion is anything over 5% is too high to apply epoxy coatings over. Some experts will argue that 8% is still acceptable. Always remember that this is a moisture % and not a moisture level.

Jeremy Stewart
Flooring specialist and owner
of Quartz Carpet

*The views expressed in this article are not necessarily the views or opinions of FLOORS in Africa.  This article has not been solicited or sponsored by FLOORS in Africa.