Cheap panelling/board options for rough wc walls?

[Safety First]

We have a little toilet built into a rough lean to on the rear of our house.
The render is really old and bubbled/cracked in places.

It needs walls that are fairly uniform and able to take some paint.

I would rather attempt cement render than skimming plaster but wonder if there are some options for a cheap ish boarding over.
Rather not go in there to hack off all the current render....


Don't want to loose to much volume. Tiny space already.....

Single skin exterior wall on one side- is a bit damp.

Plastic, plaster board (edge joins only - no skim), some type of wood, or are there materials I am not considering?

I have some experience boarding areas with water resistant neat match (££££££), boarded quite a few fireplaces with supalux board.... And can imagine getting a satisfactory finish with float coat to the walls of I was to cement render it.....

Decisions, decisions....?

 

[oldbutnotdead]

Chop the render off (treat yourself to on SDS drill with a stop chuck & a chisel), clean the pointing up & throw some external masonry paint at it.
If the render is failing outside then chop that off as well

 

[Safety First]

Chop the render off (treat yourself to on SDS drill with a stop chuck & a chisel), clean the pointing up & throw some external masonry paint at it.
If the render is failing outside then chop that off as well

Thanks. Hadn't even considered that option .