Plasterboard jointing tape

[Speedoman]

Hi

For cement boards in the shower area I use the cement board jointing tape.

For moisture plasterboards in the rest of the bathroom area, do you use the same plasterboard fibreglass jointing tape that you would use in bedrooms etc.

The moisture plasterboards are being tiled after.

Thanks

 

[Qwerty]

I use self adhesive fibreglass mesh joint tape for both. They are the same thing for cement boards & plasterboard

 

[Speedoman]

I use cement board tape for cement boards because it is alkali resistant

 

[SJPurdy]

If using cement based adhesive then the tape should be alkali resistant.

 

[Speedoman]

If using cement based adhesive then the tape should be alkali resistant.

thanks

 

[Speedoman]

Spoke to the technical department at Knauf and they told me to use alkali resistant tape if using tile adhesive.

If not using tile adhesive then use white tape as it is stronger than fibreglass jointing tape.

 

[Qwerty]

I got some advice on this some years ago.


Basically I was told that they are both fibreglass tapes, but the ones branded as alkali resistant are coated with a type of latex polymer so the alkali content in the cement doesn't break down the mesh hence why they have a thicker shiny finish to them. I was told that the coating only delays the reaction (if it occurs at all) not totally.


I posed the question of what if I used standard glass fibre tape, but primed it with acrylic primer at the same time as the substrate (after laying it of course) so alkali in the cement wouldn't degrade it. They agreed it would be fine, so that is what I did.