Show pan installation

I am about to install a shower pan as a part of the Kohler-Sterling package which includes the three walls. Should I put down roofing felt or some other material underneath? I dont want to put mortar. Thanks.

It's your call, but mortar will really beef up the base. What I did was to use a 25 lb bag of Armstrong self leveling floor compound. This is intended to fill and level a floor prior to laying asphalt tile, but it worked qreat for filling under the shower pan. I set the shower pan level, installed the drain, and then poured in the compund. It is a liquid so you can pour it in on the at the back or sides and it will find and fill the low spots. It does tend to ooze out until it sets up a bit, but I just caulked with strips of towel to contain most of it and after it set up, the rest was easy to remove. If this is on a wood subfloor, I think a layer of plastic or felt would be in order just to hold the goop until it set up.

I always use a 40 mil shower pan liner.

tmg

Kohler will know. What do they say?

i think Kohler is good about mentioning using mortar underneath, even in their basic documentation. What will they tell you when you call their tech support phone number? They may help you by defining a recommended alternative. I would like to know.

david

Without additonal support under your shower base, you will probably have movement which could eventually stess the base and cause cracking. A bed of the Armstrong product mentioned or Durabond 90 will make for a much more stable and durable installation as well as a better feel when standing in the shower.

Guy

I am getting ready to install a Sterling shower base with walls myself ("Ensemble" made of Vikrell). The installation manual seems to say it's perfectly fine fine right on the subfloor as long as it is level to within 1/8" over each dimension and the studs are plumb to within the same 1/8". They recommend using shims if necessary. That's my plan. Also, they seem more worried about people trying to install this right onto joists than right onto subfloor, which it seems is the preferred/most common approach.

There are about 22 spots of the base, plus the front lip, that contact the floor. Also, a sheet of some special woven polyester is included, the stated purpose of which is to minimize squeaks. The manual specifically says to use woven polyester type of stuff, not roofing felt, for this.

I've thought about leveling compound, but I've never used it. You basically make what amounts to a very shallow lake of the stuff the exact size and shape of the shower base and its properties as a liquid ensure a perfectly level surface, no?

Finally, as far as movement of the base, you put in roofing nails or flathead screws in right over the lip to each of the studs. That should hold it pretty well, no? I noticed the shower base in there previously had construction adhesive long the lip that contacted the studs as well. Would this be a BAD idea?