Thin set layer under mortar shower preslope
Hello all, new to the forum, thanks for having me. Background is in Commercial Real Estate Sales and Leasing, also have a few years construction experience running subs/projects just before retiring in 2008. Married for half my life with 2 beautiful daughters.
For the sake of full disclosure, I have to confess I have been on another forum with questions about a DIY Tile shower I am currently building.
I did search the forum for answers to my question and also scrolled randomly thru some of the topics. I did find a couple posts containing what I thought were partial answers but……..wanted to post my question straight up.
Now for my question: I have just finished a dry pack mortar preslope for a new Tile Shower. I see a lot of videos online that show a thin bonding layer of thin set being applied to the concrete slab (i have a single story home in AZ with a concrete slab floor). I did not apply this layer of thin set prior to building my mortar preslope. How important is this thin set layer to bond the mortar to the existing concrete? The shower is walled on 3 sides with 3 stacked 2x4s at front curb. I am being advised that best thing to do is break out the existing pre slope (only one person commenting so just looking for some other real world situations or knowledge), put down thin set and rebuild mortar preslope. The advice includes a comment that it will probably be ok as-is but………..
I do like to do things the right way, simply spaced on doing the thin set. Trying to determine how important it really is before tearing out and starting over.
Any comments, questions or criticisms will be greatly appreciated. Ive got really thick skin?
Thanks in advance for any help with this issue.
Stay safe out there!!!
Scott
Replies
You're fine as is. Preslope isn't going to move, and if you used the proper mix ratio, properly packed, keep moving forward.
I have never installed a shower preslope on a thinset bed and I've done more showers than I can recall.
Frankie
Frankie
Thank you Frankie! This helps put my mind at ease. Pre slope is well packed and sloped and smooth. Really didn’t want to break it out and could not see reason for it. Would have bee easy to do if I had remembered prior....obviously not so easy now. Have found others in threads since I posted question that have done it without Thinset. All no issues if pre slope done right. Be safe out there and thanks again!!!
I'll second Frankie's input. I assume you'll be installing a pan liner over this pre-slope. I have done a few pans this way on framed floors and was advised to start with essentially a release layer of felt under the pre-slope mortar. I also reinforced the pre-slope with wire mesh each time, though I doubt it was really necessary. Once it's in place, it has nowhere to go with the pan liner, mortar bed, and tile on top of it.
If you haven't already bought a pan liner, I really like Noble products. You can buy a PVC liner from Noble just like the stuff on the roll at Lowe's and HD, but it also makes a liner and other products of CPE, which is supposed to be a longer-lasting material. For the last few showers I have done, I've switched to framing the pre-slope with tapered shims and plywood and then bonding NobleSeal TS membrane (a tileable membrane) directly to that ready for tile. It allows you to skip the mortar bed build-up/curb build-out, which allows me more accuracy in laying tile. Noble has some very nice, very rugged low-profile drain assemblies to go with it.
Thanks Flash 28! Yes I am putting down an Oatey PVC membrane on top of the preslope then slope top mortar bed following the pre slope. Thanks for the heads up on the Noble products. They do sound easier. I will check them out.
Scott