Mitchell’s HardoPlug is an ultra rapid hardening agent, in powder form, for cement. When mixed with fresh cement, it causes rapid setting within 1 to 2 minutes and is therefore ideally suited for plugging and stopping infiltration of water through concrete or brickwork.


HardoPlug is primarily used for emergency and immediate water shut off from holes, cracks and fissures or from any other spot where the water leakage is heavy enough to impede the proper application of waterproofing system. HardoPlug has been specifically designed for stopping gushing water, it is not a general waterproofer or vapour barrier. Once the inflow of water has been stopped with HardoPlug, the permanent waterproofing of the structure should be carried out with a suitable waterproofing product such as Mitchell’s FERROSEAL or Mitchflex 2K.


  • Quick setting
  • Resists high water Pressure
  • Easy to apply
  • Economical


  • For all preliminary waterproofing work on very wet surfaces.
  • For plugging holes and cracks in water tanks prior to the application of waterproofing coating.
  • For sealing and plugging high pressure water leaks in basements, underground structures, concrete pipes and ducts etc.


The area to be plugged with HardoPlug should be cleaned as much as possible. All loose material and unsound concrete should be removed. At the point of water penetration, the surface should be cut and a dovetail or rectangular type hole be formed, deep and wide enough to allow for proper plugging. A deeper cut will result in better plugging and sealing.
In a dry container pour sufficient quantity of HardoPlug and then add Cement (OPC), add enough quantity of cement to form a thick paste. In the meanwhile keep stirring the mix till the required consistency is achieved. The HardoPlug-Cement mix starts to set as soon as it is mixed, wait for a few seconds to let it harden enough and then with a gloved hand mould this paste into the form of a cone shaped plug and force this plug into the prepared hole. Hold the plug in place applying pressure of your thumb or palm till it has set firmly sealing and cutting off the water penetration. Depending on the pressure of water and weather conditions, it will take 1 to 2 minutes before HardoPlug is firmly set in place and then the hand pressure can be released.


HARDOPLUG is supplied in 5 kg units which will yield approximately 2.5 liters of mortar.


For further details and assistance for specific application requirements and for other product information please contcat Mitchell at the addresses given below.