when should PVA be used?

Hi all, I am always keen to learn new skills, and was wondering when it comes to tiling when should PVA be used on the walls before tiling? I guess its just to waterproof the plaasterboard behind the tiles when in wet areas such as bathrooms? Do you need to PVA onto a rendered wall? Do you use neat PVA or watered down? Cheers

flyingsparks said:

when should PVA be used on the walls before tiling? Cheers

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simple to answer this question for you mate= NEVER

PVA should never be used in any connection for tiling, for the simple answer that it is water based and therefore NO-GOOD

you need to use an acrylic based primer such as BAL APD or ARDEX P 51
or BAL bond SBR

hope this clears things up for you mate

jctilingservices said:

flyingsparks said:

when should PVA be used on the walls before tiling? Cheers

Click to expand...

simple to answer this question for you mate= NEVER

PVA should never be used in any connection for tiling, for the simple answer that it is water based and therefore NO-GOOD

you need to use an acrylic based primer such as BAL APD or ARDEX P 51
or BAL bond SBR

hope this clears things up for you mate

Click to expand...

does this mean this can be applied to fresh plaster, does the primer act a waterproofer?

flyingsparks said:

Hi all, I am always keen to learn new skills, and was wondering when it comes to tiling when should PVA be used on the walls before tiling?

Click to expand...

Never, ever use PVA in tiling applications; if you need to prime use an acrylic or SBR based primer & then only when the adhesive manufacturer recommends it; but use a quality trade adhesive/grout, not chaepo DIY crap.

flyingsparks said:

I guess its just to waterproof the plaasterboard behind the tiles when in wet areas such as bathrooms?

Click to expand...

Standard PVA IS NOT waterproof, it remains water soluble & is why you should never use it on a tile base; use it in a wet area & your tiles could end up on the floor.

flyingsparks said:

Do you need to PVA onto a rendered wall? Do you use neat PVA or watered down? Cheers

Click to expand...

Based on the above - NO

xr4x4 said:

jctilingservices said:

flyingsparks said:

when should PVA be used on the walls before tiling? Cheers

Click to expand...

simple to answer this question for you mate= NEVER

PVA should never be used in any connection for tiling, for the simple answer that it is water based and therefore NO-GOOD

you need to use an acrylic based primer such as BAL APD or ARDEX P 51
or BAL bond SBR

hope this clears things up for you mate

Click to expand...

does this mean this can be applied to fresh plaster, does the primer act a waterproofer?

Click to expand...

Read JCT’s post again & mine back to the OP; most definitely not. If you need to waterproof, you must tank it. Begs the questions if your tiling why do you have fresh plaster? & what is the plaster over?

OK Thanks, got the message that you never use PVA!!

When do you use an acrylic based primer such as BAL APD or ARDEX P 51
or BAL bond SBR is it everytime you tile a wall or only in wet areas? What preperation would be required on top of an exsisting wall which I have knocked off old tiles and in places will use one coat to fill chases etc?

You only need use a tile primer if the adhesive manufacturer recommends one for the adhesive your using e.g. a gypsum plaster/plasterboard must be primed if you use a cement powder adhesive for large tiles, the background your tiling onto or for the particular tiles your using. In most cases a primer may not be required & can be detrimental to tile adhesion. If your tiling a wet area & it’s any sort of plasterboard, you should tank it if you want it to last but a waterproof tile backer board is a far better option. You also need to be careful with tile weights; plaster will only take 20 kg/sqm unplastered boards 32 kg/sqm.

Don’t use one coat plaster (or any plaster) to fill the chasses; it’s not the ideal tile base & you will have to wait for it to dry thoroughly (could be up to 4 weeks in some casses) before you can tile similarly if you use a conventional sand/cement render. If you use cement powder tile adhesive to fill & level, you can usually tile over this after 3 hours or at worst the next day. You should be using a powder adhesive anyway if your tiles are larger then around 300 x 200mm.

PVA is a plasterer’s best friend though.

What about using gypsum bonding to fill the chases to nearly full and then the powder tile adhesive to bring the chase up to level with the wall, or is it better to do all the filling using the tile adhesive?

ardex A45.

flyingsparks said:

What about using gypsum bonding to fill the chases to nearly full and then the powder tile adhesive to bring the chase up to level with the wall, or is it better to do all the filling using the tile adhesive?

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Richard C said:

Don’t use one coat plaster (or any plaster) to fill the chasses; it’s not the ideal tile base & you will have to wait for it to dry thoroughly (could be up to 4 weeks in some casses) before you can tile

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Use tile adhesive or you will still have to wait for it to dry out; Bonding is quiet soft & weak as a tile base anyway.