Externally so that external pollutants should not enter the tank.
Internally so that internally stored water does not leak out.
I would suggest doing the waterproofing treatment to the complete tank including ceiling as water vapor tends to stick to the ceiling of the tanks and eventually over a longer period of time will cause corrosion of slab steel of the tank so if you are quality conscious get it done to the full tank.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.