tiling on scratch coat ???

[PaulW55]

Hi I've done a search on this but haven't managed to answer my question

i've strip some tiles off today, the internal platerboard walls are fine but the external walls most os the plaster skim coat has come away with the tiles.
The scratch coat underneath is about three quarters or an inch thick in good condition, and flat

Can i tile straight onto the scratch coat, would i need any primer, prep etc, trying not to get it skimmed is i don't need to

cheers

[whitebeam]

I would remove as much of the existing plaster from the rendered wall and then prime with an acrylic primer which matches the adhesive your using...

What tiles will you be fixing.

[jay]

If the scratch coat is solid and flat yes it can be tiled.what area is it (shower) as for priming depends on your adh

[andy allen]

if the scratch coat is bonding plaster then it will need to be reskimmed.

[PaulW55]

the base coat is grey in colour (not cement) how do i tell if it is bonding coat on not

it is a shower area,

i usually use D20 adhesive

cheers

[Phil Hobson]

Hi is the scratch coat sand and cement? if so yes, If browning or bonding, no, if it is, sand and cement, then prime with the recommended primer your chosen adhesive manufacturer advises, if not you will need to skim imo.

[jay]

Have you thought about waterproofing

[Phil Hobson]

Note to self, I must type faster

[doug boardley]

sounds like it's a gypsum basecoat by your description, so it will need re-skimming.

[widler]

sounds like browning(gypsum) to me,as doug said it will need skimming

[whitebeam]

Good point about the gypsum coat, I jumped in thinking sand/cement for some reason..

[doug boardley]

also if it's in your shower area, you'll need a cement based adhesive, (bagged powder) not the D20 which is a dispersion adhesive.

[jay]

Good point about the gypsum coat, I jumped in thinking sand/cement for some reason..

That make two of us then BUGGER

[PaulW55]

thanks for the help

as it was a good base left i've just had a go and plastered my first wall, was impressed with the results, its looking good, still glad it bring tiled over tho