Tiling bathroom and new stud wall

[feasty33]

Hi,

I've had a quick search of existing topics but not really found what i'm after.

I am in the process of refitting our bathroom, including knocking down the wall between existing bathroom & toilet to make one room.

The existing walls are blockwork (like breeze blocks, but thinner), as was the wall i removed.

I have put up a stud wall to effectively block up the redundant door to the loo.

I plan to tile all of the bathroom walls and, having done it before, know what i'm doing with tiling onto the existing plaster/blockwork.

What i don't know is about tiling onto the new stud wall.
From what i've read i don't need to skim it, but do i need to prep it in any other way, eg primer or similar?

Also, i've read about the no-no's of using PVA as a bonding agent, but the PVA i saw in B&Q said it was ok to use as a bonding agent for tiling!?!?
It was Evostick i think.

The wall in question is 950mm wide by 2370mm tall and is in the opposite corner to the bath/shower (about 2.5 mtrs away).


Any advice much appreciated

Dave

 

[Richard C]

From what i've read i don't need to skim it, but do i need to prep it in any other way, eg primer or similar?

Use only waterproof tile backer board in wet areas, not plaster board. If it’s a dry area, you can use Moisture Resistant plasterboard & tile directly onto that. No need to skim, it’s a waste of time, money & will reduce maximum tile weight, important if your planning on using large format tiles. If you have untilled areas which you need to skim do that first (wasting into the tile area) but the PB must be acrylic primed first. Generally you should not prime unless the adhesive manufacturer recommends it but if using cement based powder adhesive which you must if laying large format or thick tiles (usually above around 250mm), it must be acrylic primed as cement in the adhesive can react with the gypsum in the PB or plaster

Also, i've read about the no-no's of using PVA as a bonding agent, but the PVA i saw in B&Q said it was ok to use as a bonding agent for tiling!?!? It was Evostick i think. The wall in question is 950mm wide by 2370mm tall and is in the opposite corner to the bath/shower (about 2.5 mtrs away).

It depends what type of PVA it was but, as a general rule, it's safer NEVER to use PVA as a tile primer, standard PVA is water soluble, will inhibit adhesive drying & your tiles may fall off if it subsequently gets wet. I’m sure there are some who are clued up but follow the advice of BNQ staff at your peril; there are no tiling products in BNQ I would personally recommend you use. Use only quality trade products, BAL, Webber, Mapei etc (but not the one in BNQ); cheap own brand & DIY products sold by in the sheds are mostly crap.

I know you say you’ve “done it before” but I would strongly advise you read the tiling sticky & forum archive posts thoroughly before you buy materials or do any more work, it may prevent you making disastrous & potentially expensive mistakes. If you’re thinking of tiling over a suspended timber floor, be aware that these can be problematic & need special consideration if you want to avoid tile failure.

 

[feasty33]

Hi Richard,
Thanks for your reply.

BTW this was the PVA that i saw
http://www.bostik.co.uk/diy/product/evo-stik/Super-Evo-Bond/87

I have weighed the tiles that i have, and a 1 mtr square pack weighs in at 15.4 kg. So i guess even adding 4 kg to that for adhesive & grout i still come in at well under the limit for the PB wall, but only just for the plastered block walls!

Because of this i presume that a ready mixed adhesive is not good enough, so would something like this be whats required?
http://www.tilefixdirect.com/product/BASPW20.html

And i take it that this adhesive needs primer to be applied first, for both the PB & plaster covered blockwork? If so what should i use?


Many thanks
Dave

 

[Richard C]

BTW this was the PVA that i saw
http://www.bostik.co.uk/diy/product/evo-stik/Super-Evo-Bond/87[/QUOTE]
It says modified PVA but as there are no data sheets, I’ve no idea what it’s modified with; neither does it state if it’s waterproof or can be used a tile primer. I wouldn’t take the risk & stick to an acrylic tile primer where recommended by your chosen addy manufacturer.

I have weighed the tiles that i have, and a 1 mtr square pack weighs in at 15.4 kg. So i guess even adding 4 kg to that for adhesive & grout i still come in at well under the limit for the PB wall, but only just for the plastered block walls!

Because of this i presume that a ready mixed adhesive is not good enough, so would something like this be whats required?
http://www.tilefixdirect.com/product/BASPW20.html

And i take it that this adhesive needs primer to be applied first, for both the PB & plaster covered blockwork? If so what should i use?

The weight will be OK but what is the actual size of the tiles? Quality ready mix adhesive works very well in the correct application but it relies on evaporative cure to set so all the moisture must escape through the grout lines. It’s fine for smaller, lighter tiles but once you start to get much larger than 250 x 250mm, setting time can be considerably lengthened & tiles can move around. It should never be used on tiles larger than 300 x 300mm & cheap adhesive may not set at all; we’ve had instances of tiles moving around & falling off the wall after a week & the OP has eventually had to remove them & start over with powder addy.

I mostly use Rapidset flexible
http://www.tilefixdirect.com/product/BARSF20W.html
but the drawback if inexperienced is the relatively short pot life of just 40 minutes; BAL SPF is also an excellent adhesive & much slower to set. It will be fine for the PB but you don’t really need a flexy adhesive over the render; probably not worth buying different adhesives if the quantities you require don’t mach. For powder addy over gypsum use an acrylic primer;
http://www.tilefixdirect.com/product/BAPR25.html

 

[feasty33]

Hi Richard,

Sorry, totally forgot to put the tile size on!
They're quite large, 361 x 276 x 9mm, ceramic.

So, to summerise:
Acrylic primer (for plasterboard only, or on both wall types? Sorry!)
http://www.tilefixdirect.com/product/BAPR25.html

Good quality powdered adhesive all round
http://www.tilefixdirect.com/product/BASPW20.html
I couldn't see a BAL product that was standard in terms of NOT flexible and NOT rapid set?

And powdered Grout
http://www.tilefixdirect.com/product/BAMXGW5.html
Unless there is a good quality powdered grout that isn't rapid setting??

Many thanks
Dave

 

[Richard C]

They're quite large, 361 x 276 x 9mm, ceramic.

Most definitely powder addy; are you sure about that sq/m weight? Seems a bit on the light side for 9mm thick tiles!

So, to summerise:
Acrylic primer (for plasterboard only, or on both wall types? Sorry!)
http://www.tilefixdirect.com/product/BAPR25.html

What are the other wall types; is it bare render & porous/dusty? is there paint, if so what sort of paint?

Good quality powdered adhesive all round
http://www.tilefixdirect.com/product/BASPW20.html
I couldn't see a BAL product that was standard in terms of NOT flexible and NOT rapid set?

These have a pot life of 5 hours, I’m sure they will be fine but I’ve personally never used either of them;
http://www.bal-adhesives.co.uk/products/ctf4
http://www.bal-adhesives.co.uk/products/wall-floor-professional
If in doubt check with BAL.

And powdered Grout http://www.tilefixdirect.com/product/BAMXGW5.html
Unless there is a good quality powdered grout that isn't rapid setting??

Similarly to their ever expanding adhesive range. It’s one of the new “one size fits all” BAL products that seem to be emerging with monotonous regularity lately; as an exclusive BAL user, I find their expanding product range increasingly confusing. It seems a bit like the “whiter than white OMO” TV adds of years ago; if you’re old enough to remember them

Personally never used it, I still use this;
http://www.bal-adhesives.co.uk/products/microflex
but it doesn’t have the colour range of the new products but if you just want white, I’d stick with it, it’s tried & tested by many.

 

[feasty33]

Hi Richard,

With regards to the weight, I put a brand new sealed pack of tiles on our digital bathroom scales (which i hope are fairly accurate!) and they weighed 15.4KG. The pack states that it covers approx 1m2, and I also calculated it to be 0.996 m2 without spacing for grout.

The other wall types are blockwork.
At the moment they are half tiled, half painted with matt bathroom type paint which will both be removed and taken back to plaster.
I have some patching plaster to make good once the tiling comes off!
So in theory, it should be bare plaster.


Dave

 

[Richard C]

At the moment they are half tiled, half painted with matt bathroom type paint which will both be removed and taken back to plaster.
I have some patching plaster to make good once the tiling comes off!
So in theory, it should be bare plaster.

Don’t bother with the patching plaster, you will have to leave it 10 days before tiling & its god awful stuff anyway. Use cement tile adhesive, that way you won’t have any delay in tiling over it & it'll be a far better tile base.

Not sure how your aiming to remove the "bathroom type" paint but don’t use a steamer or you could also inadvertently remove the plaster skim. If it’s well adhered there is no point, just score the surface well, use an SBR bonding primer slurry coat & tile away.

 

[feasty33]

Richard,

Many thanks for your continued advice, its really appreciated!

I think i am down to my last question now.
If i buy some SBR primer to make up a slurry coat to seal the old paintwork and plaster before tiling, can i use that same SBR mixed 1-4 with water to prime the new PB wall rather than buying another tub of APD primer for such a small area?


Many thanks
Dave

 

[Richard C]

can i use that same SBR mixed 1-4 with water to prime the new PB wall rather than buying another tub of APD primer for such a small area?

Yes.

On the painted walls, you must ensure the paint your tiling over is well adhered to the original plaster, as the tiles will only be held up by whatever they are stuck to & if the paint isn’t sound! Try a gaffa tape test; stick a strip of tape over the paint & pull it off slowly if the paint comes off with the tape you need to further prep the surface by scoring all over.

 

[feasty33]

Richard,

Thankyou for your time in answering my questions, it is much appreciated!


Dave