Self leveler required vs lay down tile per instructions? - TilersForums.com

[adfl1912]

I have a 12'x'12' room on concrete slab. The floor is relatively flat, but using a 8' spirit level, I can see there are slight high and low spots. I'm installing 8" x 48" porcelain tile so Im assuming they are prone to breaking easier if the floor isnt perfectly flat due to their length.

Do I really need a self leveler in this situation? I'm using a standard mastic adhesive and my thought is the thickness of the mastic will level out the floor tiles. Maybe even back-butter the tile to get better adhesion?

Im not one to skimp or take short cuts but the floor really is quite flat... but not perfectly flat.

I guess my question is, can mastic (used according to instructions) be used not necessarily as a leveler, but in it self level the floor for tile?

The most unlevelness (not a word) Ive found is less than 1/4" end to end on a 8' spirit level.

Thanks!

 

[Old Mod]

Hi and welcome to the forum.
When you say mastic, are you meaning ready mixed in a tub?
Here, ready mixed tubbed adhesive isn’t suitable for porcelain.
Back buttering porcelain is a must.
It improves adhesion by over 50%
If the sub floor is reasonably flat, self leveller isn’t a must.
You can trowel the floor then also trowel the tile, giving you the necessary lift to clear minor imperfections.
Make sure they are fully bedded by lifting the occasional tile to check you’re being consistent.
Make sure you work the tile into the adhesive.
Excess adhesive seeping between the joints is a good thing, its a sign of good coverage.
Hope this helps.
Good lick.

 

[adfl1912]

Hi and welcome to the forum.
When you say mastic, are you meaning ready mixed in a tub?
Here, ready mixed tubbed adhesive isn’t suitable for porcelain.
Back buttering porcelain is a must.
It improves adhesion by over 50%
If the sub floor is reasonably flat, self leveller isn’t a must.
You can trowel the floor then also trowel the tile, giving you the necessary lift to clear minor imperfections.
Make sure they are fully bedded by lifting the occasional tile to check you’re being consistent.
Make sure you work the tile into the adhesive.
Excess adhesive seeping between the joints is a good thing, its a sign of good coverage.
Hope this helps.
Good lick.

Yeah.. Im from the States, so all of my terminology and measurements are wack compared to the rest of the world.
When I say mastic, Im meaning the stuff in the tub, but it doesn't have to be ready mixed; there is powder form you add to water as well.
In the States, I have an option of either mastic or thinset. thinset is an organic compound and can attract mold which is why I believe mastic is the way to go. What is the product called in the United Kingdom?
I will definitely back butter the tiles.
Thanks for the information.

 

[LM]

Hi and welcome.
Without question go with a powdered adhesive and at least a 1/2inch trowel. From what you say a flat skin to the tile should be fine but as 3_fall says if you go with a notched back butter make sure all trowel serrations are in the same direction and that they run 90° to the length of the plank tile, this let’s the air escape easier.
Also assuming that your concrete slab is standard depth is it more than 6 weeks old? It has to be cured properly.

 

[adfl1912]

Hi and welcome.
Without question go with a powdered adhesive and at least a 1/2inch trowel. From what you say a flat skin to the tile should be fine but as 3_fall says if you go with a notched back butter make sure all trowel serrations are in the same direction and that they run 90° to the length of the plank tile, this let’s the air escape easier.
Also assuming that your concrete slab is standard depth is it more than 6 weeks old? It has to be cured properly.

What does "flat skin to the tile" mean? Perhaps no notches on the tile?

Just so I Understand, should the trowel serrations on the tile run the same direction as in image one? or like in image two? (serrations on back of long tile)

Concrete floor is 25 years old so it better be cured! Thanks!

 

[LM]

Trowel in the direction of image 1 on both the floor and the tile. A flat skim is when you use the flat side of the trowel where there are no notch’s to spread a thin coat of adhesive to the tile to insure good adhesion, if the floor is relatively good this way is sufficient but if you notch skim the back of the tile it would allow for more discrepancies.

 

[Steve6690]

FWIW I think you're making life extremely difficult for yourself by laying 200mm x 1200mm porcelain plank tiles onto a floor which is out by up to 6mm. If there's any "bow" in the tiles it'll be even more difficult.
Also, from what I've read about mastic here :

https://www.tiletools.com/mastic-vs-thinset-use/

it's probably not suitable for your intended use.

 

[adfl1912]

FWIW I think you're making life extremely difficult for yourself by laying 200mm x 1200mm porcelain plank tiles onto a floor which is out by up to 6mm. If there's any "bow" in the tiles it'll be even more difficult.
Also, from what I've read about mastic here :

https://www.tiletools.com/mastic-vs-thinset-use/

it's probably not suitable for your intended use.

Thats hilarious that there is actually a forum called, "American Tile Setters Advice Forum"

So yes, I had it backwards. Mastic is NOT what I want to use, but instead use thinset. Do you also agree with this?

Ill check for bowing in the tiles. Good thought!

 

[Old Mod]

Yes you definitely want to use thinset.

 

[Lou]

Yes there is and we are getting more and more members from the States joining us every day for advice