Bathroom Wall Prep And Adhesive Advice.

[Cabnero]

Hi Guys. I've got to tile my Mums bathroom later in July for which you have already answered some questions. I've just got a couple of quickies re the prep if you dont mind.

The walls are half tiled which will be coming off so no worries there. Above the tiles however, there is a painted , I think render, which has a bobbly finish, not smooth. In the main the paint seems pretty sound but I was going to scrape the walls to flatten them as much as poss. This should loose hopefully miost of the paint. I was goint to use 12.5 mm Marmox in the shower area and 12.5mm plasterboard for the rest. My questions are:

Does the wall need priming before I fix the Marmox board, and indeed the PB.
Will Dot and Dab be sufficient for the plasterboard or is it best to use screws also? If so do I need to use washers as well for the plaster boards? BTW the tiles are 600 x 300 porcelain.

I usually use Bal addy but Ive been looking and Ardex X7 seems more reasonable. Is this ok to use. Presumably its best to keep the same manufacturers for the primer and addy?

Many thanks for your assistance and any additional comments.

 

[Spud]

without seeing it its difficult to say if you get the paint off then it wont harm using a coat of sbr primer , x7 is a good adhesive so no worries there , are you going to dot and dab the plasterboard with the x7 or just the marmox boards ?

 

[Cabnero]

Thanks Garythetiler for answering. I was going to use dot and dab adhesive for the pb and the tile addy for the marmox. Red the primer I was wondering, if there is paint left whether that could or should be primed? Any advice regarding mechanical fixing of the plasterboard.
Thanks again

 

[Spud]

sometimes if you prime the paint it causes it to pull off easier in my experience ,so best advice is to do your best to remove the paint before you tile, adding screws will always give the boards a fail safe if you want to do a belts sand braces job but I recently done my on bathroom and didn't add extra screws to the areas I used plasterboard

 

[Cabnero]

Nice one garythetiler. I thought that may be the case with regards to the primer and paint which is why I was thinking about mechanically fixing the plasterboard. Do I need to use washers with the screws? If so can I use the ones for the marmox board

 

[White Room]

If you do decide to add some screws to the plasterboard make sure the heads don't break through the paper face, you could try some washers but they won't pull in as they would with the marmox boards.

 

[Cabnero]

Ok whitebeam nice one.

 

[Cabnero]

One last question. Do you allow the addy to go off or do you screw through while it's wet. I presume you use normal plasterboard screws for the pb.

 

[White Room]

You wait for the dri wall adhesive for the plasterboard to set, then drill, plug and screw (not dry wall screws) to the substrate.

 

[Cabnero]

Thanks Whitebeam. Do the screws go through the dried addy only or do you space then evenly over the entire board. Sorry I know this is a daft question.

 

[White Room]

The screws go through the adhesive locations, the adhesive should be applied with dabs and evenly on the wall then fix the board.

 

[Cabnero]

Thanks whitebeam.

 

[Cabnero]

thanks for the answers guys one thing I forgot to ask is do you use normal plasterboard tape for the plasterboard joints then cover with the tile adhesive.

 

[Flintstone]

No need to tape the joints on plasterboard unless your plastering them

 

[Cabnero]

Cheers local tiler