Pva Versus Primers | Always Use A Primer When Tiling, And Not Pva

[Scott]

Thats right scottiecom just the back and edges. Although it depends on your adhesive manufacturer, some say prime the face and some dont. You need to read the instructions to make sure.

 

[Homza]

Interesting thread. Questions about priming- In the UK do you prime every surface before you tile or only wood and plaster surfaces?
Over here the only time I prime a surface is before applying self leveling cement. Also if tiling over gypsum based self leveling (we call it gypcrete) installed by others.
Otherwise just use a latex modified mortar that is designed to bond to the particular substrate. We have ANSI 118.4 products that are latex modified for bonding to masonry surfaces and ANSI 118.11 for bonding to wood surfaces. They are adding ISO labels, Mapei has them already.
Most of the time I am setting over existing concrete. If it is a plywood floor we go with cement board/hardi/or Ditra over it.
For walls in showers I go with cement board but apply a surface applied liquid waterproof membrane. Usually the only time I am bonding to drywall(plasterboard) is for a kitchen backsplash.
Is the sealer to improve the bond, or to prevent the substrate from pulling the moisture out of the mortar too fast, or a combination of the two? Thanks.

 

[rubi]

Hi Guys now mabey at last the message about primers over pva might get through, Now all you tilers out tell the builder your working for to not do you the favour he thinks he is doing by putting PVA on the walls before you get there. Tell him whatever the substrate to LEAVE WELL ALONE:veryangry: and price accordingley for your own prep.

 

[DHTiling]

Interesting thread. Questions about priming- In the UK do you prime every surface before you tile or only wood and plaster surfaces?
Over here the only time I prime a surface is before applying self leveling cement. Also if tiling over gypsum based self leveling (we call it gypcrete) installed by others.
Otherwise just use a latex modified mortar that is designed to bond to the particular substrate. We have ANSI 118.4 products that are latex modified for bonding to masonry surfaces and ANSI 118.11 for bonding to wood surfaces. They are adding ISO labels, Mapei has them already.
Most of the time I am setting over existing concrete. If it is a plywood floor we go with cement board/hardi/or Ditra over it.
For walls in showers I go with cement board but apply a surface applied liquid waterproof membrane. Usually the only time I am bonding to drywall(plasterboard) is for a kitchen backsplash.
Is the sealer to improve the bond, or to prevent the substrate from pulling the moisture out of the mortar too fast, or a combination of the two? Thanks.

We also have Gypsum plster on the walls, so need priming if using thinset to prevent etterignite reaction.. and some times we have dusty screed floors , so a primer seals the surface to help create a bond as you say.. but not neat as this skins and will create a failure...

It can also reduce the moisture suction like you mentioned if a longer open time is required.

 

[-Woody-]

Great post. I've just purchased the Bal Primer for use on plasterboard and was wondering if I would have been better off with Bal Bond SBR?

Woody

 

[DHTiling]

APD is fine..

 

[-Woody-]

Thanks for the reply Dave. Are you saying that I should change the Bal Primer to the Bal Prime APD?

Woody

 

[DHTiling]

BAl primer is APD.. Acrylic primer..

 

[rubi]

Acrylic primers always used to be green or blueish thats how i used to tell then read the instructions

 

[inspectapart]

Re: P.v.a. Versus Primers......

Is Ultra Prime flexible additive primer o/k to use?