fixing backerboard

[littlecookie]

i've just ripped off the tiles in my shower room ,around the cubicle the walls where dot and dabbed and the water had blown the plasterboard so i was going to stud it out then screw backerboard to the studs but the block work is so uneven ive had to dot and dab it again with plasterboard ,the bloke down at topps says i cant stick backer board onto bare plasterboards even if i plaster which i wasnt going to ,he says it has to be screwed with special screws .my plan is to stick the boards on with a rapid set or somekind of no nails also screw staright to the bloack walls just to be sure it holds ...................................any advice welcomed

 

[tnarg999]

hi cookie,
the guy at Topps is probaly right about backer board onto plasterboard.

You could have stuck a backerboard directly onto the blockwork having primed the block first (BAL APD). I was in a similar postition, but used a Marmox board dabbed straight on to the blockwork, rather than plaster boarding first (Marmox is like Wediboard). I used additional mechanical fixings through the Marmox board with a galvanised large washer. This went right through the dab and into the block work where I had sunk a fischer wall fixing(wall plug).

I guess it depends on how level is the wall now you've re-plaster boarded and what weight of tile you want to use? If the walls are level and the tiles weight less than 32kg sq mtr (including adhesive), I would tile onto the plasterboard having applied a BAL or Dunlop waterproofing system first to protect the substrate.

If the walls are not level, you could get them plastered, but plastered walls hold less weight than plasterboard, 20kg sq metre I think but might be wrong.

Hope this helps....