A 1/4" trowel isn't enough for a floor tile. You want at least 3/8" to bed it in well and support it. You also need to back butter. Can't answer about stairs, and I don't like tile on stairs. You never get the proper nosing, and that creates a slip and trip hazard.

Multimax is all about the mixing and slaking. Follow the directions, and use distilled water.

Yes, prime wood substrates first, as a belt and suspender thing. Advantec is supposed to be waterproof and not wick water out of the thinset, but it also can be a bond breaker if you don't scarify it a bit first. Scarify and prime for the best bond.

Thanks McDonald. I have a 3/8 trowel too. That may have been my plan? All my tiling tools are in a box and needing sorted.

Thats inconvenient to use distilled water. Maybe I should return it to Floor and Decor and get the Platinum instead. Or does all thinset need distilled these days?

I'll get some primer for the Advantec. It was high on my list of "maybe needed". The Advantec just feels weird for adhearing products.

QUESTION: what happened to my ability to connect to the JohnBridgeForum? I get an error message that is something like this "forbidden 401" iirc.

Are you using the right bookmark for JB? https://www.johnbridge.com/vbulletin/forumdisplay.php?forumid=1

Have you posted in the Tile the World FB group? That is where most pros have moved to over JB. https://www.facebook.com/share/g/1GQEdSdyYy/?mibextid=wwXIfr

Geyser, thanks for the feedback, yes I have posted in the FB forum just a few days ago. I was an occational poster over in JB forum for over 10 years. Then one day i just got the 403 Forbidden message. I was in the middle of this project and loved having the support. Now that is gone. Your link takes me to the 403 Forbidden page too.

Geyser, can you look me up over at the JB forum, @enduring, and post the following on my latest project that I started in about May 2025: Due to the '403 forbidden', error code I can not get back to the forum for updates and contributions to the forum. Thank you CX and others for you much needed help.

This project is in the following picture. This is the dry layout. I used one of those green lasers for the first time. I found the center of the room and things look fairly good for the edges. So I need to get the primer, before the Stratamat install. I cut the Stratamat into 36" widths because as I recall it was a bear to install in 2013 because it was too wide at about 45" for me to work off the roll. I did it but hopeing having 36x45" rectangles makes the job easier in my 100sq square.

I’m away from home right now. I’ll catch you up later today.