11. Render

11.1 Refer to the Render policy

11.2 The render will not be painted until the moisture content in the render is no more than 15% as indicated by an electrical resistance test. Alternatively, it must be left to cure for a period of no less than 28 days or the use of an epoxy primer (or similar product) is to be applied to the surface prior to painting

11.3 The issue with painting cementitious substrates (concrete/render) that “looks dry” without testing the actual moisture content is that the addition of finishes such as vinyl/paint will seal the concrete and change the internal equilibrium of the concrete moisture – meaning the moisture deep in the wall will migrate towards the “observed” dry substrate and then the surface that was thought to be “dry” will become excessively moist and cause delamination of the finishes and or bleaching of the pigment in the paint system.