Tiling onto concrete floor - what went wrong?

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gpd

I have a fair bit of tiling experience: the bathroom floor and walls tiled (over a year ago, and have had no problems), and the kitchen walls tiled and part of its floor (more recently)... but I haven't had this happen yet.

I'm using BAL's excellent adhesive range, and have followed their fixing guide. However, the remaining parts of flooring to be tiled are concrete and I'm not using BAL's recommended adhesive for concrete floors. I'm using their "ctf4" and have several bags, so I would rather not purchase a different adhesive.

Basically what has happened is the adhesive didn't adhere properly to the first tiles that I started laying. The ones that I started laying were from two different mixes. I do think the first mix was too dry and almost all those tiles eventually showed themselves to have loose areas the next day, and I took almost all of them up. At a later point I ended up pulling up the rest because I could tell they were also fairly loose. With the ease that they came up, I know leaving them down would have caused problems with movement later. Most but not all of the adhesive stayed stuck to the floor rather than the tiles, although has since started coming loose from the concrete floor as well (I haven't scraped it all up yet).

I'm just glad I'd only laid a small part of the remaining floor before the problem showed itself.

I have two possible solutions in mind, other than making sure the mix isn't too dry, but wanted to get advice from those with more experience. Firstly, I didn't prime the concrete floor and I'm wondering if this has allowed the concrete to suck all of the moisture out of the adhesive, causing it to be too dry to properly adhere to the tiles (and to a lesser degree, adhere to the concrete), and would the acrylic primer seal the concrete and thus prevent the absorption and solve the problem? Secondly, I considered whether I need to put an additive into the mix with this specific adhesive in order to use it on a concrete floor?
 
Are you using ceramic or porcelain tiles ?? That ctf 4 takes about 16 hours to go off how long have you left it before going on it perhaps it didn't set I'd of just used rapid set myself
 
1st problem is you didn't prime the floor, always prime & mix primer 3 or 4 to 1.
Lay adhesive on the floor with the flat side of your trowel so it's keyed into the substrate & then comb it with the teeth of the trowel.
Back butter your floor tiles using the flat of your trowel again.
Mix your adhesive to a nice creamy consistency & you shouldn't have any problem.
 
if your using bal addy or any produst they have mixing instructions on the rear if you have never used a product take 5 mins and read the instructions that takes all the guess work out of mixing.
then lay as stef said above. also size of notch trowel is important .i mainly use a 8 or 10 mm
 
Just finished my fun job for the night. Hammer, chisel, and a load of mess made taking up the set adhesive.

Are you using ceramic or porcelain tiles ?? That ctf 4 takes about 16 hours to go off how long have you left it before going on it perhaps it didn't set I'd of just used rapid set myself

Ceramic. Yeah it wasn't walked on for 16+ hrs. The only rapid set I've used before is BAL fastflex which is great for its purpose, and it sets fast which is good for walking on but annoying that I have to do small mixes and keep thoroughly cleaning the tools, mixing bucket and laid tiles' surface. And the floor I'm tiling is very big (over 20 sqm)!

I'm using the ctf4 for the concrete portion of the floor simply because it was left over from tiling walls, and presumed it would be fine on the concrete floor as it is a rigid and not flexible substrate. BAL's fixer guide recommend "BAL Green Screed" adhesive for concrete floors but I am seriously turned off that as it states that ONE WEEK drying time should be allowed for the adhesive!

1st problem is you didn't prime the floor, always prime & mix primer 3 or 4 to 1.
Lay adhesive on the floor with the flat side of your trowel so it's keyed into the substrate & then comb it with the teeth of the trowel.
Back butter your floor tiles using the flat of your trowel again.
Mix your adhesive to a nice creamy consistency & you shouldn't have any problem.

Will do all of those this time. Thanks.

if your using bal addy or any produst they have mixing instructions on the rear if you have never used a product take 5 mins and read the instructions that takes all the guess work out of mixing.
then lay as stef said above. also size of notch trowel is important .i mainly use a 8 or 10 mm

Always do, and there certainly is no mention of an additive needed where it mentions concrete floors on the back of the ctf4 bag. The only mention of BAL's additive is "further applications achieved by including Admix AD1 to provide flexibility, improved adhesion, and reduced water permeability".

It is seeming like my two fatal flaws were that the mixes were way too dry, and I didn't prime the surface.
 
Your adhesive may be out of date!
If you've had it over 12 months and how has it been stored?
 
Just a thought how old is the concrete floor?

Think you have read the fixing guide wrong for fixing to green screed, you must tile onto it within a week..
 

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