Repointing, also known as Tuck Pointing, is the process in which cracked or deteriorated mortar joints between brick, stone, slate and other stone work is repaired. There are many reasons for mortar to deteriorate or crack. Deterioration of mortar is usually caused by extreme climate changes and inclimate weather. Damage can also be caused by chemicals such as excess salt used during the winter. Other times, it is caused by an installer using a low PSI mortar mix, which either adds too much sand to the cement ratio, or too much water to the cement ratio. Tampering mortar with water several times will weaken the cement mix.
Repointing/ Tuck Pointing is performed by grinding out roughly ¾ inches of the deteriorated mortar. If mortar is deteriorated enough to where it can be scraped out with a key and turns into dust, it needs to be grinded out until solid mortar is exposed. From there, the mortar joints would be washed off and cleaned to give the new mortar a solid area to bond to.
Conventional Repointing done with standard mortar, rather than a plastic cement morter, typically fails within a couple of years because of a harsh winter climate. Conventional mortar as a whole, does not have great bonding properties, especially when applied over an older cement.
It is important to use the proper mixtures and techniques to avoid motar failure. For example, we use a plastic cement that has a mixture of latex and acrylic. Latex is soft and flexible, where as the acrylic is hard with a high chemical resistance. Together, these additives create a plastic cement mixture. This plastic cement has superior bonding properties, chemical resistance, freezing/thawing durability and waterproofing properties.