Does Kerafex maxi Mapei like a bit of damp if present? I have been told that since cement adhesives contain cement and cement has low permeability properties it is ok to tile provided the subfloor is not completely submerged in water. I have spoken to a tiler and he has told me that i could go the liquid dpm however he found it a bit o.t.t. I would love to have other comments from people on this forum who have already come across this problem. Also would you use liquid dpm underneath the slc or brush it over the slc?Thanks again.
Dotto,
https://docs.google.com/viewer?a=v&q=cache:5A1SmlG7I2YJ:www.ardex.co.uk/pdfs/ARDEX%2520K15HB.pdf+ardex+k15+hb+technical+sheet&hl=en&gl=uk&pid=bl&srcid=ADGEEShWycUTS1onJpsJp1b3nNfIY3hc7W_3exegkMBFY2IZ3md4rPyRx4W-vcCShypeQJIVAPBwKPFZIOur0a6OwW-4jZyKDL6RsSar80igOeH-pMDiwyWVaknay-WF6x3d1Vlul7lu&sig=AHIEtbRcNeVig8QjX1sjN-Bofosh6j8N2w
Technical sheet for the SLC you are proposing clearly states that direct to earth substrates
must have an effective DPM. I don't know how bad the damp problem is there, if you have a damp meter take a reading and then call the Ardex Technical Dept and discuss it with them to see which Ardex DPM you need if in fact any of them are suitable given site conditions.
Cover yourself and do it by the book. You don't want problems arising in 12 months. The advice that other tiler gave you, in my opinion, it wasn't very professional. SLC is not stable when exposed to damp
that cannot dry out. The aggregates in it are so fine that it has very poor characteristics when exposed to water over prolonged periods. And while the tile adhesive won't suffer if it gets damp, the tiles themselves may discolour if damp is coming up from underneath, especially if they are porous natural stone, or ceramic (the biscuit on the back of the tile is porous). Porcelain might be okay, but the SLC definitely will not be okay, so don't take any risks.
I would also recommend painting that DPM up the wall too because if you're right and damp's coming in through the solid wall then you don't want it entering the SLC from the side or it will cause all the same problems as if you didn't bother with the DPM on the floor...
Best of luck with it, and don't be afraid to ask questions, especially to the Technical Depts of the materials manufacturers.
