Shower tray on slate tiles

[baggielad]

I’m installing a new resin shower tray on a suspended floor. The instructions state that the tray should be laid on 18mm marine ply. The new tray is around double the size of the old tray it’s replacing, and therefore, it will extend onto the bathroom flooring which is laid with slate tiles (300mm by 300mm) which are in turn laid on either plywood or chipboard.

My question is can I just lay the 18mm marine ply direct on to the slate tiles or should I remove them and the ply/chipboard they are on before laying the marine ply?

Thanks for any responses.

 

[AngelesPlumbing]

Up to you, mostly customer wants shower tray low as possible. Dont forget get a unibond