Pressure Pointing | Grouting
Often referred to as ‘pressure grouting’ or quite simply just ‘grouting’, this is a process which involves inserting a grout material into an isolated space – of which neither volume or configuration are known – in a concrete or tile structure. Pressure pointing can be effective on open spaces which are up to 200mm deep. The material can be injected into the space using hand held barrel guns or mechanical mortar pumps which deliver cement or lime based material through a hose – the latter method is used more frequently when the application is more thorough.
The purpose of this technique is to either strengthen or reduce water flow through a formation, it can also be used to correct faults in concrete and masonry structures. Since this approach is used to control the rate of water flow, grouting has been used since the 19th century in the formation of almost all of the world’s largest dams.
The grout material which is injected into the pour can be either:
• Solution Chemical Mixture
The cement grout is made from a cement powder mix whereas the epoxy grout is made from epoxy resins and a filler powder. This resinous grout is very durable and near completely stain proof. Since the resinous, epoxy grout is made from two different resins mixed with a filler, the cured product is extremely waterproof.
To carry out any pressure pointing work, there will often have to be a preparatory cleaning of the surfaces using high pressure water jetting equipment to ensure that the holes are completely void and to ensure that there is nothing that will block the grout material.
The main varieties of grout include:
• Non-Shrink Grout
• Thixotropic Grout
• Flooring Grout
• Tiling Grout
• Resin Grout