if anyone is deciding whether to box up in the toilet or wet areas, please make sure the board use is calcium silicate board as it is water resistant not water proof though. if use gypsum board, it will be goner when it is in contact with water/moisture in the bathroom.

I think for toilet, the box up should preferably be water proof concrete and the pipes should be working well (preferably PVC as the pipe is very lasting).

using concrete will pose a problem in future. If there is any leakage, concrete will not be visible till the entire thing collapse. For board, you can start to see visibly where is the leakage, get someone in, cut the area affected, repair the pipe, cover it up and paint over will do. Repair cost is still cheaper than using concrete should there be any leakage.

if anyone is deciding whether to box up in the toilet or wet areas, please make sure the board use is calcium silicate board as it is water resistant not water proof though. if use gypsum board, it will be goner when it is in contact with water/moisture in the bathroom.

I've been staying for 7 years and it still good