Plywood, MDF, or ? - for boxing in back to wall toilet and making "cupboard"

[Oxbow16]

Hi

 

The bathroom refit planning continues...!  

 

We're going for a back to wall toilet.  The boxing in will continue up to the ceiling, with a door above the toilet and internal shelving.

 

We want the boxing/cupboard to look as much like the joining walls as possible, and will paint them the same colour so it looks more wall than cupboard.  

 

What's the best thing to use?  It won't get wet as such, but will obviously be in a moist environment.  I was thinking ply to begin with, but just seen you can get moisture resistant MDF.  Or are there better options than those?  

 

Many thanks   

[Temp]

We have something similar in MDF. Looks just like plaster when joints filled and painted. However we had cracks appear at joints as it shrank slightly. Remade it with glued joints not just screws and it's been fine.