Hydraulic Cement

Preparation 
To stop seepage or flowing water, enlarge the crack to a width and depth of at least 2cm (3/4”) by using a screwdriver or chisel to ream out a square or inverted “V”. This will allow the mix to “lock-in” with expansion. Clean and dampen the concrete surfaces for good adhesion.

Mixing
Add 3¾ parts Hydraulic Cement to 1 part potable water and thoroughly mix to the consistency of “putty” (more material can be added to stiffen the mix). Mix only small amounts. Warmer water will accelerate whereas cooler water will retard the set times.

To Stop a Leak
Form a ball of the putty-like material and force it into the crack or hole as it becomes warm and begins to stiffen. Work the material into a square or inverted “V” area and smooth off to match the surface area.

To Stop Flowing Water
Seal crack from top to bottom (point of maximum water pressure) and then force a plug of the hardening material into the remaining bottom area. After the initial set, the surface area may be dampened and finished by hand or trowel.