Waterproofing treatment only 1% building construction cost but when ignore, it can be responsible for almost 90% of the damage.
Concrete is not Gastight & Watertight unless the pores are closed.
waterproofing means treating a surface to protect it from the damage that water could bring .

Which area in a building need Waterproofing →

Excellence In Lite Weight Concrete

Waterproofing Treatment Site Work Example