Building Steps to the bath

[dabomb3k]

at the moment i have a sunken bath that have steps leading up to a small flat area surrounding the bath..

im going to be taking this out within the next week as this was built previously with chipboard and has gotten wet and started to crumble..

my question is, what should i use to build the steps ? obviously its going to need to be able to withstand adults weight, but also i would like to be able to tile directly onto the steps

im also on a budget so the cheaper solution the better

 

[tpt]

marine ply is really the only option that will work in the long term

 

[Happyplumber]

WBP Ply will be fine ,tank it if you are worried about water Ingress