Tiling on polystyrene board?

[user123]

I guess this may be a complete nightmare idea to you all, but I have a few of 4'x3' polystyrene boards left over from insulating an 8'x8' potting shed I then recladded and turned into my nice and cosy and really neat studio space (will happily supply photos if interested:-)

Now looking at the boards, would it, in principle, be possible, to glue them with whatever adhesive (after I've cut them into the desired shape), onto a plasterboarded wall and tile onto that, and grout, to create a protruding 3D effect? That leads me neatly into any thickness polystyrene - a friend of mine for example fancies mosaics of (gold coloured and mirror tiles) stars on her bathroom wall and would love them to stand a bit proud from the surrounding tiles...if it was possible surely the possiblities for creating false arches etc could be quite interesting?

If you get what I'm on about over to you... thanks..

[pjc]

as long as it will hold the weight if its the hard solid type not the soft white stuff we used to fix it to the floors with cement based years ago then tile on top :Pete

[user123]

as long as it will hold the weight if its the hard solid type not the soft white stuff we used to fix it to the floors with cement based years ago then tile on top :Pete

Jewsons flooring insulation polyboard, yes, it's white seems firm and compact enough and when you cut it you have bits of polystyrene clinging to every avaliable surface - is that the right stuff? And did you mean cement based adhesive both between the plaster board and between poly board and tile or, would I need, if I wanted to use mosaic glass, special mosaic adhesive? Apologies if I seem a bit dense about this...

[pjc]

no that ain't no good u need the dense stuff adhesive would be ok