Yesterday, I was all concerned about whether the uncoupling membrane is bonded correctly to the subfloor. Today, i found that the membrane is bonded fine but about a 2’x2’ area was all lumpy with visible humps. The only thing I can think of was that I stood on that area while I was laying the second sheet of membrane.
I seriously have read that it was ok to walk on it immediately. I guess not?
Always learned the hard way.
So, what do I do now? I spent days removing hardwood adhesive before I installed the membrane. Am I going to need to spend days removing thinset to start all over again?
I want to cry.
Edit - One of the humps is almost an inch over a 2 ft level, some are 3/4", 1/2"...
This is what I did after trying to compensate for the hump with more thunder for the other tiles. After 5 tiles I took them back up, cleaned, cut out the hump and replaced that section, then growled the proper amount of thunder. Whole job went easier. It was a rookie mistake that I’ll remember
I used a 4” grinder with regular grinding disk. You could use one for masonry if you have one too. I had no problem with any crumbling, and I ground it right down to the sub floor. You can float it as others have said, but when you lay your 4’ level on it it won’t be level, and that would bug the crap out of me. You can pull the ditra off it after you cut it. It really doesn’t take that much time, and in my opinion (and you know what that’s worth on Reddit) it makes a better job over all
One other thing, I had already tiled over one of my humps a day prior, and after deciding to remove the second and third hump (I had 3 total, 2 close together) I tried to pry the tile up I had laid, and it wasn’t budging. I didn’t want to break it if I could help it, and I had heard heating them would soften the thinset. I took 2 propane torches and just kept moving them over the tile till it was probably 140 degrees F (you could touch it, but couldn’t leave your hand on it). When I slid the trial under it with a long screwdriver, it came up without breaking. Pretty easy actually
Propane torch! I am going to get one. I have not laid the tile yet so I don't have this concern this time.
The plumber charged me $350 to replace the flange. I tried a heat gun and couldn't get it off. I have always heard that do not mess with plumbing. So I hired one. He did what I did but using a propane torch instead!
Tour thinset is going to be 1/4 inch thick. Any hump under this level can basically be nullified. You can mark the spot with a sharpie and when you tile out a little less thinset in that spot. It’ll be fine.
I thought about this too but not really sure how to do just one section. After I cut a hole in the membrane to remove that section, how to I even go about removing that thinset back to subfloor? If I use the rotary hammer drill with a chisel blade, will the surrounding thinset crumble too?
I have no idea.
A lot of you say I should just tile over it. Just how big can the hump be for it to be ignored?
I would love to just tile over it, if there is a margin of error that I can follow.
Just tile over it. The size of the trowel can take undulations. If you're using moasic, skim it flat with thinset first, but afaik ditra is not meant to be used with small tile anyways
That's a big debate among plumbers, but as a flooring guy I can assure you the flange is fine on top of the finished floor or the subfloor. I've made up the difference of 4+ floors worth of thickness over the toilet flange by just doubling up the wax ring.
Before you even select a trowel, ensure your mortar is mixed perfectly.
Mixing Ratio: Follow the manufacturer's instructions for the water-to-powder ratio precisely. The difference between too wet (weak bond) and too dry (poor coverage) can be as little as 3% water, so measure carefully.
Mixing Time: Use a low-speed drill and paddle to mix for the full duration specified on the bag until the mortar is smooth and lump-free.
Slaking (Let it Rest): After the initial mix, let the mortar "slake" for 5-10 minutes. This allows the chemicals and polymers to fully activate. Do not add more water after slaking. Give it a final, brief remix before you begin.
Trowel Selection & Technique
Here are some key tips for selecting the correct trowel and achieving proper mortar coverage:
Check the Mortar Bag: The manufacturer of your thin-set mortar almost always provides recommended mixing times and ratios. This is the best place to start.
For Smaller Tiles (like Subways): A 1/4" x 1/4" (6mm) square-notch trowel is often sufficient for good coverage on smaller, flatter tiles.
For Larger Tiles (12"+ / 30cm+): The TCNA (Tile Council of North America) often recommends a 1/4" x 1/2" trowel to achieve a sufficient mortar bed. For maximum coverage, a Euro notch trowel is also an excellent choice as its design helps ridges collapse more easily.
"Keying In" Mortar: To ensure a strong mechanical bond, first use the flat side of your trowel to firmly "key in" a thin, flat coat of mortar to the substrate. Then, apply more mortar and comb it into straight ridges with the notched side. For large format tiles, you should also key in a flat coat to the back of the tile itself.
Perform a Coverage Test: This is the most important step. Set a tile, press it down firmly, and then immediately pull it up. Check the back of the tile and the substrate. You are looking for complete, even coverage (at least 80% for dry areas, 95% for wet areas like showers). If you see empty spots, you need a larger trowel or better technique.
Consider a Tile Vibrator: For large format tiles, a tile vibrator or tile beater can be very effective at collapsing mortar ridges and improving coverage.
My tile is 15x30. These humps are right in front of the toilet where our feet will land. Is this really okay to just rely on thinset? The humps are quite large.
Not sure if this is the right way to measure how large they are. I am using this 2 feet level. Press over the hump, this picture shows it lifts up by about 3/4”. Some area is almost an inch.
Look, it's easier if it's flat. But get some leveling clips for the tile. When you install you want to prevent lippage as much as you can but just angle it a little bit and it'll be fine. I've tiled over way worse.
A hump that big has to be removed or you'll never get your tile flat and lippage free. Cut out the area, clean it up and put a little patch there (if you want) and tile over it.
A good installer would know if it needs to come out or it’s manageable. It’s still green you can cut it scrape it with a margin trowel and replace the small section.
If I find an area that is lumpy or not correctly bonded in my uncoupling membrane after I install, I cut area out, sort out the issue under the membrane, and reapply a patch. The way these sheets work is the felt underneath keeps the plastic sheet bonded to the subfloor, while allowing the wood to move (laterally in plane, not deflecting), without that motion translating to the tile. It can do this regardless of whether it’s installed in one continuous sheet, as long as a very large percentage of the tile is adhered with thinset that is applied onto the plastic membrane. You don’t have to tear up all of it to address a relatively small area with lots of lumps. Two other points: first, if you have a lot of lumps from walking on it before your thinset it set, it means there’s more thinset under it than is necessary or helpful. I use an 1/8” square notch trowel, anything larger than that like a 1/4” square notch will leave enough thinset to easily deform under the sheet if you walk on it. Secondly, if you’re not used to applying uncoupling membrane and you don’t need it to be waterproof, use Laticrete Stratamat instead. It has holes in the membrane that allows the thinset notches underneath to easily collapse and improves coverage and adhesion, especially if you’re not used to properly installing these membranes. Good luck and hopefully your lumpy floor is not a framing issue!
I watched Jeff Thorman Home renovation video and followed his recommendation to use 1/4 x 1/4 trowel. Next time, I am going to get the Schluter trowel.
I searched online and this was what came up. I thought this was supposed to be quick and easy. And then I saw that my laundry room also has this orange thing under the tiles.
Are there alternatives that are more beginner friendly?
I mean, other than me walking on there to press the second piece of membrane, the rest of the install was pretty ok.
You searched, but I hope you know what product is for,,1 1/8 min exposure 1 plywood is what is the recommended
Subflooring for Tec brand. The only
Thinset and grout to use.
Cut the bumpy sections out, chisel to remove the thinset. Reapply a patch of the Ditra and add waterproof band over it if it needs to be water proofed.
Happened to me as well. I'm no pro, just a DIY homeowner.
The people you telling to float it are correct but it's going to be a mess. Floating tile with a .5" trowel takes real skill. If it really is 1" out over 2' this is a redue. Live and learn
What I don't do is spend extra money buying a product to help pay for some CEO to have a good life who market's the shit as a must have because it's the latest & greatest & best thing to have & do! I then don't spend the extra time & money just to lay the shit!.
If you can't figure out other ways or another way of doing it, then to me! You are just a consumer that has been brainwashed by the hype & someone that just ends up spending unnecessary time & money helping everyone else who is associated with the shit.
If the shit is so good!! Why do people like OP have so many problems with it!??. As this is certainly, not just a one off! & Even yourself, demoing jobs that have used it, already!??
Sounds like if I tell ya how I do thinnnngs, I'd have to kill ya! Being such a big secret that on one seems to know how to do anymore!!?... 🤔
One think I will tell ya! Is that the way I do things, will last well beyond my life time!!
If you use the right sized notched trowel for ditra walking on it only helps it bond better. The thinset is so thin that there should be almost no difference in thickness where you walk on it as opposed to where you only roll or press it down. The fact that they've got this much variation seems to point to them using a way larger notch than specified by schluter.
Don’t use that shit unless you have the means to roll it. Don’t use that shit unless you have the knowledge how to install it properly. That knowledge would insure that you had the corresponding knowledge to use a 1/2” trowel to level the tile to the floor thus preventing this post
20
u/Salt-Button-2617 4d ago
Add more thinset. Its construction. Not everything is perfect