Tiling bathroom floor urgent help needed please

Hi guys I am in need of an urgent help
We've got a new built house and due to all the costs to get it we've ended up a bit toooo tight with cash hence I'm doing any extra work needs doing by myself. I am usually open to all basic diy jobs but never tiled before.
I've installed the plywood on bathroom and ensuite (1.2 cm) And went to Homebase to get a primer. I did ask for advice and I was offered one.
I applied the primer to the plywood (seemed to be white like paint) allowed it to dry as the guy instructed. I laid tiles with flexible rapid set mapei adhesive. After two day when walking on top of the tiles I could feel that they aren't firm. Tried to take one up and the surprise, they came up easily.... it was a it of a shock for me when checking that primer I realised it's a paint primer... so yesterday I went to top tiles and bought the bal bond primer, but couldn't carry any work due to a disturbing pain in my back.
Any advice you can give me guys? Should I scrape that first "primer" out or just apply the new bal primer? Or anything else I can do? We are really lost As we wanted to move on before Christmas but things went to a tragedy....
Thanks for whoever is going to help me and merry Christmas to all of you.

You will have to lift all the tiles - remove all the adhesive - sand off the paint primer.
Then make doubly sure that the flooring boards are firmly fixed/screwed down.
Then apply the new tile primer according to the instructions - and when appropriate carry on tiling as normal.

If you are not used to manual work your back troubles could come from all the bending and kneeling thats involved in floor work?

I have already lifted all the tiles and could easily scrape the adhesive of the floor too as it really didn't stick at all, it did however stick tiles firmly which I think I will need to buy new tiles as scraping every single one is not worth the effort. I haven't sanded the floor yet as I was hoping I can just get away with applying the new primer on top of it but needed to double check with somebody that knows... will do as you said.
My back indeed hurts because of the work as I had to tile kitchen walls and floors, bathroom, ensuite, laminate floor throughout the house and indeed I'm not used to this

Always make sure the sub floor is fully screwed down into the joists, not just nailed.

Neat pva glue and screw 12mm ply over the top.

Tile straight on top, I never prime, never had problems In last 10 years.

Only thing priming will do in my eyes, is to stop the adhesive going off to quickly when on the floor, if using rapid.

You also need to be so careful with rapid, as if it's gone off slightly on the floor, the tiles won't stick correctly.

I didn't put any glue between the plywood and what I believe is a chipboard, I've only used screws with 12cm distance between each one and the plywood seems to be solid and not moving. Due to the size of the floor, the rapid adhesive didn't get hard before I was done. The thing is, the adhesive was stuck to the tiles that it impossible to scrape but not to the floor

Doesn't make sense to me, tile adhesive sticks to bloody everything...

Other tiles, paint, blar blar..

Tiles adhesive needs a flexi additive .
http://www.screwfix.com/p/mapei-lat...tracking url&gclid=CIb3vPGXkNECFSEM0wodm1AMlw

xr4x4 said:

Always make sure the sub floor is fully screwed down into the joists, not just nailed.

Neat pva glue and screw 12mm ply over the top.

Tile straight on top, I never prime, never had problems In last 10 years.

Only thing priming will do in my eyes, is to stop the adhesive going off to quickly when on the floor, if using rapid.

You also need to be so careful with rapid, as if it's gone off slightly on the floor, the tiles won't stick correctly.

Click to expand...

PVA is not suitable for tiling. The slightest hint of moisture and it's live again. Take a read of this: http://www.accesstraininguk.co.uk/news/post/2013/07/12/Prime-or-PVA-before-Tiling.aspx

OP, Remove all traces of the paint primer and I would personally speak to Home base Customer Services as they have given incorrect advice.

12mm ply is no good for tiling either. 18 mm minimum, primed back and sides to prevent moisture ingress and you can tile straight over it.