Do I need to back-butter my tiles?

[essexsi]

Hi all,

I have been reading a great deal on this website as I have a DIY job. I am fitting 600x300 ceramic tiles to the walls and 300x300 ceramic to the floor in a walk in shower that will be tanked.

I was all set, thanks to advice on here , to use a 10mm square notched trowel for the adhesive.

However, I have been reading other threads which has confused me. The advice is that I may need to back butter the tiles and also use a round notched trowel. This is because of the tile size and that its being fixed in a wet environment.

I think it is because I have been reading too much I have info overload!!

Is back buttering where you apply adhesive to the wall/floor, apply adhesive to the tile, then fix the tile? Do I need to do it to either my wall or floor tiles? Still a bit confused round or square notch?

Thanks for any help. Cheers Si

 

[Perry]

all floors should be if you are not using a solid bed trowel its easy 😛ete

 

[beanz]

all floors should be if you are not using a solid bed trowel its easy 😛ete

Why? I'm just curious, as i've never seen anyone do this, except for on light stone where they are worried about the ribs bleeding through!?!

 

[White Room]

I tend to do it because of the profile on the back of the tile

 

[Perry]

all floors should be solid bed thats why i use PTB if you have scissor lifts on them all day you need to

 

[doug boardley]

back buttering is giving the tiles a ribbed bed of adhesive, back skimming is giving the back of the tile an un-ribbed skim of adhesive, these methods are to be used with normal spreading of your adhesive ie on your wall/floor. I use a round notch trowel on floors and areas that are subject to a lot of water, this is a solid bed technique. A square notched trowel is used in areas that aren't subject to drenching.
Hope this clears things a bit

 

[White Room]

Glad your on the ball Doug, back skimming is what I meant to fill the profiles😳

 

[Perry]

i allways use a 13mm square trowel

 

[Mozza]

Pete, do you mean you use a 13mm square for floors? What would you use if your after 100% cover on walls?

 

[225driver]

i was always told to back skim the floor tiles as you need 100% coverage back skimming fills any voids on the rear of the tile then trowel floor as normal should get 100% coverage. This is what i do please enlighten me if im wrong

Andy

 

[doug boardley]

you've been told right 225driver

 

[225driver]

Cheers Doug thats reassuring

 

[beanz]

I honestly can't see why you would need to back-skim!?! Surely if you are floating the tile into the addy it'll go into the voids too? I know when i've layed a tile, then pulled it up, the whole tile had adhesive on; it doesn't just sit on the ridges...

 

[doug boardley]

as whitebeam mentioned beanz, it's when the biscuit is profiled, it fills out the profiles and makes sure you get total contact

 

[essexsi]

Thanks for all your input.

As its a shower room the floor will be getting wet regularly, so from your info I will need a solid bed under the 300x300 tiles going on the floor. I will get a solid bed trowel.

Now with the 600x300 wall tiles I take it I will be ok with a 10mm square notch trowel with adhesive only on the wall, no back buttering on the tile. Correct? If it makes any difference there is a sort of profiling of small squares on the back of the tile. What I am trying to say is that its not smooth!

Thanks very much for your help. Si

 

[White Room]

I would probably use a bigger trowel if the walls arnt to flat but would back skim the tiles to fill the profile

 

[Perry]

Pete, do you mean you use a 13mm square for floors? What would you use if your after 100% cover on walls?

Depends on the tiles i use 13mm on the walls with 600x600 that what i tile most of the time 😛ete

 

[doug boardley]

Thanks for all your input.

As its a shower room the floor will be getting wet regularly, so from your info I will need a solid bed under the 300x300 tiles going on the floor. I will get a solid bed trowel.

Now with the 600x300 wall tiles I take it I will be ok with a 10mm square notch trowel with adhesive only on the wall, no back buttering on the tile. Correct? If it makes any difference there is a sort of profiling of small squares on the back of the tile. What I am trying to say is that its not smooth!

Thanks very much for your help. Si

I'd back skim them Si

 

[essexsi]

Thank you all for your input. Very much appreciated!

The walls have been skimmed, lovely and flat so no excuses!

So 10mm square notch to spread on the wall should be ok, and then back skim the back of the tiles just to fill the profile. Is that just to build the sunken areas level with the rest, or should the skim be over the back of the whole tile?

Sorry to ask more, but when putting the big tile on the wall how much pressure should I put on it to bed it in. If spreading 10mm on the walls, should this be pushed down to about 5mm or more? I don't need a rubber hammer for it do I !!!!

Thanks for your time and help. Si

 

[White Room]

Just to fill the whole of the tile profile which should give more a solid bed behind the tile, check the tile by putting one on and pushing and perhaps sliding slightly to one side and then taking off to give some idea how much coveridge there is on the tile.

 

[beanz]

I'd be very surprised if you weren't getting 100% coverage with a 10mm trowel anyway, if the wall is as flat as you say. 😉

 

[Bolter]

Thank you all for your input. Very much appreciated!

The walls have been skimmed, lovely and flat so no excuses!

So 10mm square notch to spread on the wall should be ok, and then back skim the back of the tiles just to fill the profile. Is that just to build the sunken areas level with the rest, or should the skim be over the back of the whole tile?

Sorry to ask more, but when putting the big tile on the wall how much pressure should I put on it to bed it in. If spreading 10mm on the walls, should this be pushed down to about 5mm or more? I don't need a rubber hammer for it do I !!!!

Thanks for your time and help. Si

Walls are skimmed with what? Have you checked it can hold the weights you want to put on it?

Tiles and Adhesive Weight Per Square Metre - THE TILE SOURCE

 

[essexsi]

Thanks for all your input.

Thanks for the link bolter, another thing to worry about!! It was skimmed with finishing plaster as underneath the old tiles was browning plaster on breeze block.

The tiles are 600x300 ceramic and at a guess are 0.8mm thick, I will have to check tomorrow. With a 10mm adhesive bed that takes me over the 20kg weight limit by my calculations. Oh bugger!

How do you get that below the limit though? Surely one 600x300 tile is the same as two 300x300?!? Is it all to do with the adhesive thickness?!

cheers Si

 

[beanz]

8mm ceramic will be fine. Your bed won't be 10mm, that's just your trowel size. Once you've pushed the tile home, it'll be about 3mm i imagine. 😉

 

[essexsi]

Thanks beanz. Appreciate that. I'm easily confused at the moment, I have read everything to do with tiling but it just gets muddled up!!!

Just to confirm, checked today and the tiles are 8mm thick.
Do you think I will be OK with 600x300 ceramic, 8m thick with a 10mm square notch trowel, pushed down to 3mm?
Does tanking affect the weight at all?

Thanks for all your help! Si

 

[beanz]

I've no idea on weights for tanking membrane's, but everything you hang on the wall needs to be taken into account. "Usually" any tiles under 9mm thick should be fine weight wise, and i can't imagine 1m of membrane making much difference to be honest. 😉

 

[essexsi]

Thanks for your time beanz.

Really put me off doing it when I went through to bolters link! You have reassured me a bit, but there is still a little doubt nagging. Sometimes its best not to know these things!!

This really has made me realise what goes into this tiling malarky!

All the best Si

 

[beanz]

No worries mate. 😉

In all honesty there are a lot of tilers out there that have absolutely no idea about max weights for different substrates, so i wouldn't sweat it too much. 😀

 

[essexsi]

Cheers chap.
I have found this forum to be very friendly and extremely helpful. Not so helpful that someone has offered to come round and do it for me though!!

Cheers Si

 

[smurf21]

For a large format tile like the one you have i would still back skim the wall tile..but after putting one or two on just pull a tile of and see what coverage you have on the back of the tile this will tell you all you need to know..

 

[essexsi]

Thanks smurf. Will def be back skimming them!

I will pull a couple off and take a look, I guess I am looking to get as close to 100% coverage as possible.

Is it ok to just put the tile I have pulled off straight back on. Or do I have to scrape off all the adhesive from both wall and tile and do it again?

Cheers Si