By Sam McNaughton, Sika Technical Services Advisor - Flooring

Surface Preparation

A Sika Tramex Moisture Meter offers a rapid and effective testing method to ascertain a screed’s suitability for a resin finish. The size of a standard calculator, the moisture meter comprises probes that are pushed onto the floor, and a gauge that measures the substrate’s moisture content.  

I’d like to install a resin floor, but the substrate beneath the existing surface is likely to be damp in places, which will affect the new floor’s long-term performance. Breaking-up and replacing the old substrate will add considerable time and cost to the refurbishment, so is there an alternative solution?  

For a high-quality resin floor installation, the moisture level of the substrate beneath should not exceed 4% by weight. For substrates which record higher levels, there is an industry-approved system capable of reducing moisture and ensuring a screed’s resin-based suitability.

Depending on the area of the slab, it’s recommended that multiple readings are taken to give an accurate representation of its moisture content. For an alternative method, the calcium carbide test is advised. It involves taking core samples from a concrete floor which are crushed and mixed with a chemical compound – calcium carbide.The process takes a few minutes per concrete sample, but it is considered to be a more accurate moisture reading method.
Attaining an accurate substrate moisture reading is essential for a resin floor’s long-term performance.Concrete and screeds which exceed the 4% moisture level will result in the resin floor to de-bond or suffer osmosis: floor ‘blisters’ caused by escaping moisture. Sika has the solution to eliminate such issues – Sikafloor®-81 EpoCem®, a guaranteed temporary moisture barrier that can also be used as a self-smoothing floor screed.
A three-part, epoxy-modified, cementitious, fine textured mortar, the Sikafloor® EpoCem® system comprises a moisture-tolerant primer, Sikafloor®-155 WN. The primer allows moisture to pass from the substrate to the Sikafloor®-81 EpoCem® which scavenges the excess moisture lowering the percentage to <4% by weight, leaving a resin-ready surface.

Liquid Barrier

To ensure its performance, the Sikafloor®-81 EpoCem® must be applied to a minimum 2mm thickness and allowed to cure for around 24-48 hours depending on the substrate temperature, before being over coated with a vapor tight seal coat. The substrate temperature should be a minimum 8°C before the resin is installed. Economical, fast and easy to apply, the genius of Sikafloor®-81 EpoCem® is its superb ability to remain liquid resistant, yet permeable to water vapour.With businesses facing ever-tighter health and safety standards as well as environmental regulations, the demand for resin flooring will doubtless increase as the 21st century progresses. Sikafloor® EpoCem® system is the high-performance platform on which many of these seamless, safe and aesthetically-pleasing surfaces will be built.