I am rennovating a toilet which sits under the stairs. Its a 1960 home with suspended wooden floor. But the toilet under the stairs has a step down and follows the same level as the garage. this makes me suspect there isnt a damp proof membrane. There has been no issues as far as i am aware(as i havent lived in house) - but before we do tile it and go do the work is there anything i should test or i could do before its tiled?
