Tiling on plaster

[DanG]

Hi Guys, been reading around and saw a reply on another thread by Dave quoting British Gypsum's tech sheet on bonding coat plaster. Went to the BG site myself and read the full sheet. It says there the weight limit for tiling on a bonding plastered wall with 2mm skim is 20kg/m2 which I believe includes weight of adhesive. I have just had 2 walls in a bathroom bonded but not yet skimmed and wondered if anyone had any ideas of how to get round the weight limit so I have a full choice on tile finish. I was thinking wedi board dot and dabbed with dowels but although they do make 4mm and 6mm boards they recommend 10mm min for walls. The corner of the bathroom where the shower will be I have already made provision for using aquapanel,wedi or tanked plasterboard so no problem there. Regards, Dan

[GazTech]

Hi Dan,
If the bonding is flat, screwing boards to it will be fine. Be sure that your fixings are into the block or brick behind the bonding plaster. I think the reason for boards being thicker on walls is because on stud walls, fixed at 300mm centres, a thinner board will still flex between the studs.......Gaz.

[DanG]

Hi Gaz, thanks for the reply. The walls are pretty flat so I guess I could use the thinner board. I really don't want to remove the brand new plaster from the wall. I was also thinking that using a board would mean no need to skim. Save 2-3mm thickness there so less messing about blending tiling to door architrave. Cheers, Dan

[GazTech]

The skim coat of Gypsum is the weakness, if onto plasterboard, removing it gives more weight limit from 20kg to 32kg per m2.....what is under the plaster skim on your walls ?

[DanG]

Hi Gaz, the walls in question are brick. The coating at present is new Bonding Coat. They are waiting to be skimmed with Thistle top coat. The present finish is flat. The builders are doing a good job but I was not there when the walls were bonded. I'm not saying I knew about the weight factor but I did want sand/cement rendering to beef up the walls after doorway alterations. The wall is rock solid though with the Bonding applied. As other walls in the house were being done with bonding they assumed I wanted the same in the bathroom except where I'd specified Aqua panel to be fitted by others. I'm not blaming the plasterers as they probably assumed I'd be fitting lighter tiles. However I want the choice of tile and all the ones I like including Travertine etc are heavy ! Dan.