That is really cheap. Almost seems impossible.
I called a contractor just to quote for the conversion :-
(i) cheap method - just overlay the tiles = $800
(ii) expensive method - hack and re-waterproof and re-lay tile = $1,300.
I has this evil thought to purpose puncture the waterproofing in the toilet then get HDB come and do.
Upstairs/downstairs 50/50.
I so bad hor!!!!!