plasterboarding over existing ceiling

[pyounger]

my daughters new gaff has a fairly large bathroom with a ceiling ruined by some idiot sticking polystyrene tiles on it (yes it doesn't look like it's been touched since 1965!). I have no idea what they've used as adhesive for these tiles but trying to get one off is practically impossible. its like the tile has partially melted into the adhesive!

So I'm thinking plasterboard! But is there any reason why I shouldn't plasterboard over the polystyrene tiles? I'm also thinking of using MR board

 

[Alastairreid]

There was a thread on this same subject a few days ago, apparently the tiles give off cyanide gas and other nasties if they catch fire..even when sandwiched between plasterboard.
The consensus was to remove them.

 

[SFK]

Pyounger,
As above (Alistair) the Link to similar discussion here:
https://www.diynot.com/diy/threads/polystyrene-tiles.486258/#post-3957017
Summary of that is.... Best not to Overboard polystyrene tiles, better to scrape off polystyrene tiles with a Scraper or (perhaps) a Garden Hoe and then overboard.
sfk

 

[pyounger]

Thanks everyone for your input