Courtesy of DriTac Flooring Products LLC
I want to use a combo moisture control/adhesive system, but I keep hearing I need 100 percent coverage. Is it really that important? And how do I do that?
Larry Scott, VP of field technical services at Clifton, N.J.-based DriTac Flooring Products LLC, answers:
Unlike bond-only flooring adhesives, MS polymer or urethane moisture control system adhesives must be applied completely and meticulously. Such projects hinge on total connection between the flooring, adhesive and substrate—you need to create a monolithic membrane and 100 percent coverage of adhesive to the back of the boards, or moisture penetration of the wood flooring will result, potentially causing the entire system to fail. Such a mistake would be similar to rolling out a polyethylene film and cutting holes in it. Anything short of complete board coverage will negate the moisture control feature of the adhesive altogether.
An equally important consideration is the flatness of the concrete substrate. Not flattening the subfloor properly could result in the boards not being properly bonded with the required adhesive membrane, crippling the installation project and voiding any warranty that might be in place.
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To ensure 100 percent coverage, start by cleaning the substrate, inspecting its flatness and correcting any areas to be within flatness requirements. Throughout the application process, the recommended trowel must be used in tandem with a 100–150 pound roller. Doing so will not only vastly improve your likelihood of achieving total coverage, but it will also prevent any warranty from being voided by improper usage of a trowel or roller. During the process, periodically check the adhesive coverage by pulling an installed board and inspecting its backside. If it is at all lacking coverage, scrape up the adhesive altogether and reapply fresh adhesive until coverage is 100 percent. Utilize the V-notched side of the proper trowel to meet the necessary spread rate. While not required, keying or flat-troweling the adhesive onto the concrete could also aid the process and prevent subtle errors.
