Why do some contractors drill holes in the bottom blocks when installing an interior sub-floor system?
The theory is that it will help the system function by letting the water drain from the block wall. The reality is that the water is leaking out of the wall already. That’s why you called a waterproofer in the first place!! By drilling holes in the block, you may initially evacuate the water faster, but you also allow silt and other impurities into the system and over time clogging the system.