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View Full Version : How dry does the preslope have to be before putting down membrane


Thalia53
Apr 12, 2018, 01:51 PM
Putting in a tile shower and I have put down the dry mix preslope and ready to put in the rubber membrane. How dry does the preslope need to be before laying the rubber membrane?

massplumber2008
Apr 12, 2018, 05:22 PM
Hi Thalia

I usually use a FAST SET mortar for my preslope, but if you didn't then it needs to be dry enough to walk on, if you will, because it takes a lot of working the vinyl membrane to make the pan and that means you are walking, kneeling on it, etc.

I'd also mention that after installing a preslope mortar (or dry mix) I install a layer of tar paper (#15 felt paper) in between the preslope and the vinyl membrane just to cut down on the abrasiveness between the preslope and the new vinyl membrane.

Hope that helped...

Mark