What is it, and where is it used?
Stopgap F78 is a one-part, two coat water-based waterproof surface membrane that cures to suppress residual construction moisture where relative humidity (RH) levels are up to 95%. Unlike two-part epoxy resin based systems, it comes ready to use in a bottle, which can be resealed for future use.
Pigmented blue to allow visual control of coverage uniformity, Stopgap F78 can be used over concrete and sand/cement screeds and, like any effective waterproof surface membrane, can dramatically speed up the installation process in a new build. This is because residual construction moisture can be suppressed without having to wait for the moisture to evaporate naturally, which takes approximately one day per millimetre, up to a thickness of 50mm.
Why it is needed
Waterproof surface membranes, or damp proof membranes, are required when a subfloor records RH levels of 75% or above (or 65% or above if wood floors are being installed) when measured with a digital hygrometer. Waterproof surface membranes may not be necessary in every installation, but if a floorcovering is installed over a subfloor containing excess moisture, it is highly likely that, further down the line, the presence of moisture will cause the floorcovering to fail, so testing for excess subfloor moisture is a crucial step in every installation.
So Stopgap F78 can help to protect against floor failure. But how does it work?
Stopgap F78 waterproof surface membrane is applied in two coats directly over clean and absorbent surfaces using a pre-coated roller. The technology behind Stopgap F78 means that, when cured, it creates a waterproof film over the surface of the subfloor, effectively suppressing any excess residual construction moisture. At the same time, the composition of F78 still allows the trapped moisture to slowly evaporate at a much reduced rate, which protects the subsequent subfloor preparation products and any floorcoverings installed that may be sensitive to moisture.
Each coat of Stopgap F78 waterproof surface membrane will be dry within 30 minutes, after which the flooring installation can proceed without delay.
Find out more
You can find out more about Stopgap F78 and the rest of our range of waterproof surface membranes on our website, or watch it in action in our video.
If there’s a product in the F. Ball range that you’d like to find out ‘why it works’, please let us know.