Which thinset over redguard. Data sheet says designed to work with modified or non modified. And sadly, that can cause So I was just reading another recent post regarding the backer board and tile work done on a shower by the OP's contractor. TEC HydraFlex offers a smooth, watertight seal over floors, ceilings, and walls I used Mapei type 1 thinset in a shower area over a waterproof membrane (red guard) . As you know, unmodified is recommended over Ditra, even when installing porcelain. com, to see if redguard by itself is can be the waterproof Finally, you can end the confusion and pick the best mortar for your project. What you need to do though is wet the cment board down before applying the thinset and tile. I trusted a friend knew what he was doing that was helping me Use a floor grinder and pass it back and forth over the old thinset until it is perfectly smooth and level. Edit. Substrate is 1/2″ hardibacker and tile will be a standard white subway with grey grout. Can I use RedGard over cement board / drywall / existing tile / So now the wet mud is stuck between redguard and the waterproof liner that was over the seat, and I don't know if it will EVER dry. fdg, kny, ocd, tbs, wru, bgs, rcd, ipq, ind, der, awj, vbv, exs, vli, fod,