Redgard over shower pan mud [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-24-2012, 09:02 AM
Can i apply redgard over shower pan mud as extra protection,even though i have a vinyl pan liner installed under mud

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Richard Tunison
06-24-2012, 09:15 AM
No. You will be creating a "moisture sandwich". You want the water that gets through the grout to migrate through the deck mud down to the liner and out through the weep holes in your clamping drain.

Did you install a pre-slope under the liner?

06-24-2012, 10:14 AM
yes have preslope under final mud pan just thought since im doing the walls with redgard over durock that has no vapor barrier behind it that i might do the shower pan as extra protection thanks

06-24-2012, 10:30 AM
The pre-slope is under the vinyl liner, right?

Richard Tunison
06-24-2012, 10:32 AM
Your construction should look like this except omit the wire mesh.

06-24-2012, 10:49 AM
I still have thoughts regarding how much water really soaks through deck mud and actually leaves the shower through the weep holes.

I picture the deck mud staying constantly wet. More like a sponge. It would have to be completely saturated and have more water being added to make it so wet that it would drip water into the weep

Have a decent grasp on gravity. Also capillary action and lots of fun stuff. What keeps the water from just sitting there contained within the deck mud and growing mildew and mold?

Lets say the grout does leak. Now you have wet deck mud. Will it ever dry out? If you didnt take a shower for a month and tore that floor apart. Would you guys expect to find dry deck mud that shed its moisture out so beautifully into the weep holes? Or find a moist stagnant smelly mess?

These are just thoughts. I build my shower floors similar to above. No mesh but we use hop mop shower liners here.

Im gonna do a test for the fun of it. Will take left over deck mud and pack it somewhere. Once dry i will drop water on top and see how fast it appears and hopefully drips out of the bottom. Maybe its so sandy that it flows much better than im expecting.

As we get smarter and develop new products the idea of using a material that leaks on purpose seems silly to me. 100 years ago when we got portand and sand and lime and natural earth deposits it makes sense to build with whats available. Now we can make materials using machines.

Happy Sunday. Love learning here.

06-24-2012, 03:21 PM
pre slope to drain then oatley vinyl liner then sloped mud to drain.I never put felt or plastic behind durock on the shower walls so im going to add redgard to face of durock then tile

06-24-2012, 04:19 PM
Mike, you have an adequate shower pan. Just use your direct bonded waterproofing membrane on your shower walls and you'll be fine. :)

My opinion; worth price charged.

Richard Tunison
06-24-2012, 04:35 PM
Good on you Mike. Now we want to see pictures of your progress!

Houston Remodeler
06-24-2012, 06:00 PM
I still have thoughts regarding how much water really soaks through deck mud and actually leaves the shower through the weep holes.

Wait until they clog. :eek: Then you'll find out how important they are. We do a fair amount of business on the forum concerning clogged holes and the resulting damage.

Gary K
06-24-2012, 07:00 PM
Like Paul said, if the weep holes are cloged, then you just have a bed of muck, breeding mold and who knows what else.

10-16-2012, 08:05 AM
My tile contractor plans to not use vinyl in the shower pan because he doesn't like the way it folds in the corners pushing out the hardibacker -- he will put redguard/hydroban on the pan as a moisture barrier -- what would the picture look like in this case? Thanks,

Richard Tunison
10-16-2012, 09:22 AM
Hi J.

When using a vinyl liner you need to notch the wall studs to accomodate the thickness of the liner and folds.

When using a liquid membrane you must use a drain that has a proper bonding area such as the laticrete drain made just for that system. Another option is using the "divot" method. You can do a search here and see what the divot method is all about.

Edit: I see this has been answered in your original thread but I'll leave it here.