Would you prime this concrete floor?

[DJT75]

Hi
Doing my first bit of floor tiling this weekend & I'm not sure If I need to prime it or not.

It's a 3 sq metre porch, currently has carpet & underlay on top of some crappy old very thin 'plastic looking' council flat tiles. The tiles are completely loose from the concrete below.

There doesn't appear to be any adhesive to pull up, it would simple be a bit of a scrape around & a good hoover to leave a decent concrete floor to tile on. But should I be priming it?

If so what products would you recommend & how long do I have to leave it before I can start tiling.

I'm laying 300mm-300mm ceramics using BAL rapid set adhesive & BAL wide joint grout. I assume 5mm grout lines are appropriate here?

thanks

 

[grumpygrouter]

I would just give it a good clean and a vacuum, then use a diluted 1:1 with water solution of BAL APD. This just helps to lock the dust in. Tile when dry....less than an hour I would say. 5mm joints will be fine.

 

[DJT75]

I would just give it a good clean and a vacuum, then use a diluted 1:1 with water solution of BAL APD. This just helps to lock the dust in. Tile when dry....less than an hour I would say. 5mm joints will be fine.

Perfect thanks.

 

[DHTiling]

Or just a wipe over with a damp sponge on such a small area....use the flat side of the comb to burn in the adhesive then comb out the toothed bed..

 

[chrisroe]

why not prime

if in doubt then prime

i prime every job and i just dont know why this question keeps getting asked ?

 

[DJT75]

why not prime

if in doubt then prime

i prime every job and i just dont know why this question keeps getting asked ?

erm....because I'm new to all this

 

[doug boardley]

erm....because I'm new to all this

lol:lol:, I tend to prime most substrates with a 1:3 sbr to water mix, as grumpy says, if only just t seal the dust in

 

[Ajax123]

Might be better to use SBR or Epoxy in this instance. Unless I am mistaken Bal APD is an acrylic. Old Council Vinyl Tiles used to be stuck down with styrene based glues (like Evostick) Styrene Butadiene dissolves acrylic so has the potential unless you know the floor is perfectly clean to give you some problems long term. Neither SBR nor Epoxy will be affected the same way.

 

[chrisroe]

erm....because I'm new to all this

Sorry i wasnt having a go at you

just the question i think maybe the training schools need to look at some of the info and regular questions we get asked on here and maybe take our advice on

 

[DJT75]

Sorry i wasnt having a go at you

just the question i think maybe the training schools need to look at some of the info and regular questions we get asked on here and maybe take our advice on

No worries.
The training does cover it - like you some of the trainers say if in doubt just prime it. But I was interested in the view of others equally as experienced & as you can see I've had a variety of answers, including a completely different angle from Ajax123.

However. this stuff has been down for donkeys years, it's a small porch & I've just shelled out for some APD on a job I'm not getting paid for (mother-in-law) so it's going down! :yikes:

 

[heavytrevy]

I always prime if im waterproofing over hardiplex /plaster/concrete.
If ur just sticking/tiling with thinset to a mortar screed / concrete slab u can get away with using a damp rag a couple squares ahead of where ur workin.

Also if ur tiling hard concrete anywhere from 35 mpa- 50 mpa i recommend
shot peening or and acid wash so ur thinset has something to grab to, although not needed if the slab has been broom finished /wood floated.

Hope this clears a few things up.

Regards
Trev

 

[Bolter]

I say if in doubt, prime it! Always follow the directions on the bottle