Edit

The gap wasn't suppose to be there in 1st place. That is where the idea of having a mortar base comes in...to be parallel with the kitchen cabinets. & kitchen cabinets shud lie flat on the mortar base.

Hi... Just wanna ask what is the safest way to install storage water heater tank. Is it straight up on the wall or up the ceiling? It is about the safety that I am concern about especially when its up on the ceiling. Cos normally it is installed on walls...