Stopgap F78 is a solvent free, one component, ready to use system which dries rapidly to provide a waterproof surface membrane. Stopgap F78 impedes the passage of residual construction moisture from affecting subsequent floorcovering installations, therefore allowing early installation of floorcoverings in fast track building programmes. Stopgap F78 must be applied in two coats and can be used to isolate residual construction moisture where relative humidity values are up to 95%. It is pigmented blue to allow the user to visually control coverage uniformity.