I have taken a new direction on my shower pan after speaking with someone from the company that supplies the paint on product that I am using (Redgard).

Here is the summary...

- I have put down the first mortar bed to form the pre slope for the paint on liner with approx 1/4" slope per foot (1/2" near drain to 1 1/4" at wall). We used a quikrete sand topping mix. This is a blend of sand and Portland cement right out of the bag. I think about 3 to 1 mix sand to cement. After 2 days, you can rub your finger or a broom across the top and it will slowly brush off the top layer of the bed. If you broom across the same area several times you could broom away approx 1/8” of surface. This is what one would expect from a normal deck mud (I believe). Can I redgard on top of this “deck mud” now? If so, do I need to do anything to the deck mud mentioned above prior to redgard coating?

- Should I water test the redgard? If so, what is the best way to do this?

- Redgard instructs to add some sealant between the redgard and teh drain, but this doesn't make sense to me. Should I add any sealant between the redgard and the drain? If so, can you explain type of sealant and where to seal?

- I plan to redgard the first mortar bed mentioned above, and the curb made of 2x4, and go about 12” above the mortar bed on the plywood inserts in between the studs. Then add second mortar bed with deck mud on top of redgard (1 1/4” near drain to 2” thick at wall)). Then add durock to the walls and curb. I plan to keep durock about ½” above the final mortar bed. Then redgard and seal all of the durock as well. Do you think that this sounds reasonable? If not, please let me know what you recommend.

I'm not sure where you got your information or directions to doing a shower pan, conventional drain and liquid membrane but its all wrong.

To do a liquid membrane with a conventional drain requires you to make a divot around the conventional drain and build the shower pan in one shot.
Once the mud bed has cured for 72 hours you apply the liquid to the pan and into the divot covering the bottom section of the clamp style drain. After you have done two or three coats of liquid you can finish assembling the drain clamp with silicone and place some tile spacers over the weep holes in the clamp drain. You need to make sure the weep holes do not get blocked. Next step is to fill the divot with drypac mud to the proper height.

For the above method all backer board should be installed first including the curb area.

All the walls,curb and mud bed can be coated at the same time.

If you have access to be able to change the drain to a Schluter Kerdi drain it makes the whole process much better and easier.