Tiling Advice - Any good reason I cant use mortar as Wall Tile Adhesive

[SledgehammerSteve]

Christmas Greetings All

Can Anybody give me any good reasons why I should not use mortar to retile entire bathroom walls with large ceramic wall tiles (31cm * 41cm each tile)

The problem I have is the walls from top to bottom aren't exactly plumb/square, and to get the wall square means either replastering the wall square (and then waiting 1-2 months for it to dry - correct me if I'm wrong), OR making up the gap with the tile adhesive. Problem is the gap comes to a maximum of 1/2 inch. and all the ready mixed tile adhesives are 3mm max thin bed. I was going to build the bed up 3mm a time but it takes 2 days to dry out and I'd still be doing the job next Christmas. I sucessfully stuck a few tiles using unibond waterproof cement tile adhesive which to me seems to be a really good product - much better than the crappy unibond thin bed readymixed which I started off with then took down cos I didnt like the way it was setting (slight cracks in places)

I could continue using the cement adhesive but as it needs to go on pretty thick in places, and isnt particularly cheap, I am seriously considering using a mortar mix. It doesnt seem all that different to me. I was hoping somebody could warn me of any dangers before I start. I was thinking of using a mix of 1: 0.5 : 6 portland cement,lime, silver sand. Will I be able to tile on top straight away (probably 1 row at a time until it sets). Any worries about mortar drying out and shrinking / spoiling tile layout. Can it be applied as fairly substantial blobs rather than continuous as I will need some play to get the tiles even, square and vertical. Anything else?

Thanks for any advice

(I'd be interested to hear what John (Schmidt) and AerMAX think)

SledgerhammerSteve

[Andrew Gabriel]

I think tile adhesive also contains, as name suggests, adhesive. I suspect tiles might pull off mortar without a lot of effort.

Also, I think you will find accurately placing tiles, getting them level, and not having them slide down the wall pretty impossible if you are having to slap 1/2" of mortar or tile adhesive behind them in one go. It does sound to me like you are going to have to use a two stage process; first get the wall flat (at least, a lot flatter than 1/2" out -- doesn't need to be finish coat quality), then tile the flat wall.

[Christian McArdle]

Why not plaster the wall flat with the mortar (instead of bonding plaster), let it set for a couple of days and then use proper waterproof adhesive for the tiles?

Christian.

[take away nojunk]

Don't use mortar for tiles, it won't work, its not an adhesive (the tiles wont stay up for long if at all). Dot and Dab the walls to make them plum then skim next day, wait 48 hours and seal, unibond and water mixed is fine for this, then tile as normal, email me if you want more advice or are not sure what i'm on about, Tel

[Dave Plowman]

I think they used to use mortar in the old days - I had a splash back in my kitchen so done. And they took some removing as the walls were also skimmed in mortar, with a thin skin of plaster on top.

[Dave Plowman]

You ever tried removing mortar splashes from a variety of surfaces when its set?

[take away nojunk]

I did of course mean plumb !!!!!

[take away nojunk]

same as paint, but is paint an adhesive?? Maybe i should have said its not a light materials adhesive, its used for heavy gauge materials i.e bricks & blocks, you don't see many bricks & blocks stuck to other walls now do you!

[Andrew Gabriel]

In the old days, I think it was done with sand/cement/lime render, and then a very thin coat of cement, maybe pure with no sand, or just with just a small amount of sand, to stick the tiles to the surface of the render. (I was told, but it was a while ago and I might have mis- remembered.)

Modern tile adhesive will be much easier to use though.

[SledgehammerSteve]

Hi When I used the Unibond cement based adhesive (which behaves like mortar and spreads on wall using plasterers trowel, but I dont know if its any stickier than mortar), I put on about 8mm thick in 1 go with no problems with the tile slipping. They've set really well too- in fact stuck onto the wall like the Rock of Gibralter! which is more than I would have got with the Unibond

3mm ready mixed. I was planning to use a dryish mortar mix and hope it will behave the same way as the cement based tile adhesive already used. I think I'll have to try out a single tile first to check how it behaves and sets, unless there are any more good reasons why this is going to end up as a failure.

SledgehammerSteve

[Toby]

Yep, this is definitely one case where the powdered tile adhesives outperform the ready-mix generic stuff by a mile.

[Rick Dipper]

I had a bumpy wall, I used "dollops" of tile adheasive placed onto the tile. You them press the tile into place.

You can only do one row at a time as you have to keep the things there while they dry. This is IMHO a job where having time an patience makes it better, mine is OK, but not brilliant, I was short on time.

Grouting was fun, that had to be built up in two layers, because in places it was a long way from the "slot" to the wall.

Rick

[Dave Plowman]

I *think* mine was actually repairs to war damage, as no other room in the house had this type of 'plaster'.

Yes, but mortar based ones are pretty expensive.