Poor adhesive coverage on tile?

[hellboy]

Hi guys,

Finally got to start my tilling which didn't go too well! Using 7mm thick 200x100 subway, BAL SPF onto Elements backer board with a 8mm trowel.

Laid a couple of rows in the shower and checked the odd tile for coverage. I'd guess I'm getting around 80% on average, even when giving the tiles a little push forward and to the side.
As the coverage was poor I removed the tiles and tried again, but no joy. I'm conscious of the requirement for 95-100% coverage on shower walls, so need to ensure I do this properly.

The adhesive is like peanut butter consistency, troweled onto the wall and then combed vertically at 45 degrees. When laying the tiles, I'm giving them a little push to ensure a good bedding (apparently avoids air pockets).


The tiles also have an annoying .5mm ridge around the edge, which makes using the cross spacers a right pain the backside.. Any tips there? we're aiming for a 2mm grout joint. Are you supposed to push the spacer all the way in?

Watched a %^$ ton of YouTube videos and read advice, never quite as easy once you get that trowel in your hand!!

Any advice is much appreciated and will no doubt save me some cash (more adhesive and tiles!).

Thanks all and have a good weekend.

 

[JaimieH]

Can't see your image I'm afraid. Generally speaking if your trowel isn't achieving the right coverage on the back of your tiles then the first option is to increase the size of your trowel. A 10mm would be better in your case. The other option you have is to back skim each tile with the flat side of your trowel (or a 4" scraper). This fills all voids and increases the coverage as well as greatly increasing the bond with the adhesive. This is something that is usually more necessary with larger format tiles than smaller ones but in your case it would definitely help. Don't mix your adhesive too dry in this heat and If your tiles are ceramic it would be worth sponging the backs of them with water before laying too. As for using spacers I always push just one leg into the joints and remove them before grouting. Good luck.

 

[hellboy]

Thanks Jamie,

Tips are much appreciated. I'll get out and grab me a 10mm trowel and another bag of adhesive! Funny you mention about the heat, I was paranoid about the adhesive going off too soon, only had the stuff in the bucket for a couple of hours and it seemed to be drying out. Question on that, the 'bucket' time says 5 hours. So mix what I'll use in that time, but do I need to cover the bucket?

 

[JaimieH]

No you shouldn't need to cover the bucket, just mix smaller amounts so that it doesn't go off too quick.

 

[hellboy]

Thanks Jamie.

Last question, I promise!

I've just checked through a box of the tiles, seems the majority are 'cupped'. Cost 15 quid a sqm from CTD, should I have got the more expensive ones? Can take them back if needed.

Cheer man

 

[JaimieH]

It's your choice but you'll struggle to get an acceptable brickbond finish if you have cupped or bowed tiles. If you are stacking the tiles it might not be too noticeable though. How are you doing it?

 

[hellboy]

Brick bond, the bow isn’t huge but definitely there. About a mil when on a flat surface.

 

[JaimieH]

Once the whole wall is tiled and grouted you'll probably not even notice, especially if you've chosen a similar coloured grout to the tiles. I can't see it though so it's easy for me to say that.

 

[hellboy]

Thanks, I think I’ll just crack on and cross my fingers, this ‘little’ diy project has seriously dragged!

 

[JaimieH]

It's character