Help with uneven floor after using SLC twice!

[DevinD]

Hello everyone, first post here... I've started renovating my guest bathroom and I've gotten to the point the last thing on my list is flooring and then I'm good to reinstall my toilet and the new vanity. I've used the SLC twice now. The first time there were some uneven spots and it seemed to be a bit wavy on the surface, so I thought maybe it wasn't enough. I used a bit more the second go round and so far have raised the floor about 3/16" to 1/4" in height, but I'm still having the same problem.

I've primed the flooring per the directions both times and am applying it directly on top of the concrete subfloor.

Just to outline why this is an issue, I'm using click and lock porcelain tile that needs the floor to be absolutely level and even. I'm using the underlayment that came directly from the store, recommended by the manufacture. The tiles aren't lining up right and have a wobble in several places.

Steps I've taken:

- I've sanded down a few spots that somehow made some "points", basically like little mountain tops. Still had the wobbly tile issue.
- I've laid down the SLC once with the exact amount of water recommended for the mixture and noticed it was almost grainy in some places. With that I assumed I had possibly done one of two things: Not mixed it thoroughly enough, or it was too dry.
- Second jab at the SLC, I mixed it VERY thoroughly with the maximum recommended water and allowed it to dry for about 36 hours. Still same problem.

P.S. I used a trowel to "coax" the SLC to move around in order to make sure it was a bit more even prior to leaving it.

I'm looking for sort of two possible solutions. One being the mistake I may be making with the SLC, or what can I do to easily bring the tile to a more level position. Banging my head against the bathroom wall here... literally and figuratively.

 

[Mark Brown]

Did you prime it really well and what are you laying it over?

 

[DevinD]

Great question, I'll add this into the initial post. I primed it both times until the floor was pretty well saturated and pink. I'm laying it directly onto concrete subfloor.

 

[Mark Brown]

Hmmmmm...
that is a doozie, usually when stupid things like that happe with slc its over worked, over watered or under primed.

Sounds like none of these?

Wish I was more help.

Wait a second.... in two lifts you think you maybe raised the floor 1/4 of an inch?

 

[DevinD]

Hmmmmm...
that is a doozie, usually when stupid things like that happe with slc its over worked, over watered or under primed.

Sounds like none of these?

Wish I was more help.

Wait a second.... in two lifts you think you maybe raised the floor 1/4 of an inch?

Correct, in two lifts. It's about flush with the flooring from the hallway next to the bathroom now. I was thinking it may be because I had not used enough or raised the floor level high enough to even out the high spots, however the floor was completely coated both times (especially the second layer). My only concern is the flooring becoming too high at this point. Thanks for the active responses Mark!

 

[Mark Brown]

Yeah mate, you just didn't use enough.

Slc isn't really what people make it out to be, I would never recommend it unless looking for a 1/4 or more. It doesn't flow at 1/8 well at all.

I'm gonna say that's what is at issue

 

[C.J.]

What self leveler are you using? Some flow better than others and they can be tricky when doing a thin pour.

So now you need to map out your floor and mark the high and low spots so now you know exactly where you need to direct your attention whether it be sanding down or adding more leveler. Using a straight edge or level you need to crawl around and map out your floor. This will help you determine what you need to do next.

 

[DevinD]

Thank you both for the help.

I used Mapei Self Leveler Plus, so not sure if that is one of those that wouldn't flow better than others.

Moving forward now, what would be the preferred method: Raising the floor some more (noting that this would push it pretty dang high at this point), or just trying to sand it down?

 

[Mark Brown]

Get a straight edge on it like CJ says, then break out a 14 inch trowel and float it.

Are most the "waves" all in one direction and the same ish height? If thats the case, then it is easy to fill the gully.

Self leveler plus from mapei is a consumer grade novaplan which is all I use. It does not love being poured low, it can be done but it isnt happy about it.

You gonna be alright and we can figure this out without adding any more bulk height..... unless its a whole lot worse than I imagine

 

[DevinD]

Get a straight edge on it like CJ says, then break out a 14 inch trowel and float it.

Are most the "waves" all in one direction and the same ish height? If thats the case, then it is easy to fill the gully.

Self leveler plus from mapei is a consumer grade novaplan which is all I use. It does not love being poured low, it can be done but it isnt happy about it.

You gonna be alright and we can figure this out without adding any more bulk height..... unless its a whole lot worse than I imagine

Thank you for the reassuring words... its definitely been disheartening to say the least. Trying to do something ourselves to save a bit of money and still improve value of our first home here haha. I'll plan on marking out the low or high (depending on which is the worst upon closer inspection) with a pencil and post the progress here. I can't thank you gents enough!

 

[Mark Brown]

Got any pictures of this??
If you got what I think you got, you wont be in a lot of trouble.

 

[DevinD]

Got any pictures of this??
If you got what I think you got, you wont be in a lot of trouble.

Sorry for the late response. I’ve attached a few photos. For reference the strange looking marks are spots that had peaked for some odd reason that I had sanded down. The gap under the level is what the problem is I feel. Upon further inspection it seems the area closest to the walls are higher than the middle. So it’s sort of valleyed in the center, with a little waviness.

I watched a few videos the past several days about ‘floating’ tile on a floor. Just sort of looks like a dryer mixed mortar and the tile goes on top? Not sure 100%… feeling uneducated but trying to learn!

 

[DevinD]

Still stuck on this problem if anyone has any specific suggestions!

 

[C.J.]

Couple options since you’re doing a floating tile. You can try and repour leveler but since that didn’t go so hot the first two times prolly best not to try it again. Mark suggested hand floating the low areas. That’s a good idea that most pros would do. May or may not be your thing. You can also build up the low areas with layers of roofing felt. Layer them out like a topographical map. Or you can lay something down in the low areas like a dowel or use tap cons screwed down to the appropriate height. Just something that you can use for reference to gauge how high you need to float up those areas so you’re not guessing. Sorry for not having one single magical answer but instead you have a few options. A roll of roofing felt might not be so bad since it’s not permanent. You can play with it and adjust it as necessary.

 

[DevinD]

Couple options since you’re doing a floating tile. You can try and repour leveler but since that didn’t go so hot the first two times prolly best not to try it again. Mark suggested hand floating the low areas. That’s a good idea that most pros would do. May or may not be your thing. You can also build up the low areas with layers of roofing felt. Layer them out like a topographical map. Or you can lay something down in the low areas like a dowel or use tap cons screwed down to the appropriate height. Just something that you can use for reference to gauge how high you need to float up those areas so you’re not guessing. Sorry for not having one single magical answer but instead you have a few options. A roll of roofing felt might not be so bad since it’s not permanent. You can play with it and adjust it as necessary.

Thank you for the advice CJ! I’ll try and see what I can do with the roofing felt first and if it doesn’t work out I’ll try another route.

 

[Tile Tom]

Why the floating porcelain tile? Why not a traditional mud job?

It sounds like more work than it's worth trying to monkey around and make that system work.

 

[C.J.]

Here’s a traditional tile job that I coulda swore was a floating tile until one popped up and I saw thin set.