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Doing an elaborate bathroom remodel. I have some specific questions about the mud pan.
What is the correct mud mix and thickness?
Is expanded sheet metal typically used to reinforce the pan? If so what steps are taken to prevent puncture of the liner?
Is it best to let the pan cure before getting on it to set the tile?
This shower is too deep to reach from the outside to the back. The pan is curbless with floor framing recessed enough to allow atleast 2.5″ of mud and the necessary fall from outside the shower.
With the above considerations would wet mud set be the way to go?
Thanks in advance for your brilliant input.
joe d
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Joe, I would begin by pre-sloping the substrate to the drain flange before installing a polyvinyl liner. Has a metal pan already been installed instead of a polyvinyl liner? Most tile distributors sell 80 lb bags of floor mud that will do just fine for your pan. If your local distributors don't carry pre-mixed floor mud, you can purchase 60 lb bags of Quickrete Sand Mix at HD for about three dollars per bag. If you have access to portland cement and sand, the typical mix ratio is about 4:1 sand to cement. You're going to mix your mud with a minimal amount of water, just enough to allow the mud to look like damp sand. The reason for this is workability. You're going to float this pan by hand and shape it with a wood float. If it's too wet, the job will be tedious, messy and ultimately frustrating. There are various techniques for floating a pan. If you're working with an adjustable PVC drain strainer, set the strainer to the desired height above the liner, about 1 3/4" is fine. Take into account how much fall you want from the shower wall to the drain. Tile size is an important consideration. The larger the tile, the more difficulty you may have when setting the tile over a steeply sloped pan. Obviously, mosaics conform best to steeper slopes than 12X12 tiles. About 1/8 to 1/4 inch of slope per foot of run is fine. Cover the metal strainer with duct tape and trim neatly. Coat the body of the strainer and adjustable threads with vaseline to prevent the mud from locking the adjustable strainer when the mud hardens. Protect the weep holes on the drain collar by glueing a paper coffee filter with spray adhesive to the drain collar. This is important, the weep holes must remain unclogged by pan mud to ensure that excess water has a place to drain. Sounds like you're floating a recessed pan to a point just shy of level with the existing floor surface. No curb. After mixing your pan mud, spread several shovel-fulls along the length of one of your walls. Using a wood float, tamp the mud to form a horizontal ledge about three inches wide and spanning the length of the wall. The thickness of this ledge should be equal to the height of your strainer plus your calculated slope - about 2 1/4 inches, maybe, for your job. Using a level, ensure that the surface of this legdge is flat and perfectly level. Do the same at the base of the remaining three walls, so that you have a continuous mud ledge all the way around your shower. With your remaining mud, fill in the center of the shower pan. You will cover the drain strainer with mud, if your measurements were correct. Using a wood float, firmly pack and compress the loose mud. Tremendous force is not necessary here, just enough force to increase the density of the loose mud. Using your level as a screed, or any other suitable straight edge, place the screed to rest across the pan on your level ledges and gently cut away the excess mud that you packed by "pulling" the screed across the bed toward you. Use your wood float to pack and fill and voids and to smooth the surface. Use a level to check for depressions that may not be readily visible. Now, find the top of your strainer under the mud. It should be about 1/2 inch below the surface. Take a small piece of wood scrap, maybe 12 x 1 X 3/4, rest the edge of this small wood screed ontop of the drain strainer lengthwise and rotate it in a circular manner to cut your slope around the drain. Work the slope with your wood float to make an easy transition. Use a steel trowel to finish the surface. When complete, raise the height on the adjustable strainer to the thickness of your tile plus thinset. I recommend allowing the pan to cure before setting your tile. You could wet-set the pan while the mud is still plastic, but if you make a mistake and need to pull out or move a tile, it becomes a nightmare because you'll pull the pan mud with it. Some setters advocate sprinkling the pan with dry thinset and then spraying with a mist of water before setting the tile. I'm not confident of the resulting bond from this method. The best way to wet-set is to soak your tiles in water if non-vitreous, and back-butter with thinset before sticking onto the mud.
*More info from the dark side...pictures included.
*Thanks to both of you Frank P. and Mongo.I feel comfortable that my questions were answered between the two of you. Gotta run and meet the plumber.joe d
*You're welcome Joe, and a big thanks to Mongo. The master has spoken, with pictures to boot! 'Nuf said.
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Doing an elaborate bathroom remodel. I have some specific questions about the mud pan.
What is the correct mud mix and thickness?
Is expanded sheet metal typically used to reinforce the pan? If so what steps are taken to prevent puncture of the liner?
Is it best to let the pan cure before getting on it to set the tile?
This shower is too deep to reach from the outside to the back. The pan is curbless with floor framing recessed enough to allow atleast 2.5" of mud and the necessary fall from outside the shower.
With the above considerations would wet mud set be the way to go?
Thanks in advance for your brilliant input.
joe d