Tuckpointing Seals Small Cracks, Averts Major Repairs

By Thomas A. Westerkamp  
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Sealing small cracks in mortar joints is a proven method of sealing the building envelope, as well as minimizing future investments of time and money in maintenance work. The more seasons a cracked joint is open, the longer the time water lies in the space and freezes in colder weather.

Serious damage can occur not only to the joints around the crack but to the brick or block itself. Entrained water will peel off the surface of brick or block materials, exposing it to further damage.

Tuckpointing is a two-stage procedure consisting of cleaning out old mortar and damaged bricks or stone from the joint and tuckpointing, or replacing, the brick, stone, and mortar. While a hand chisel and hammer will work, a good cleaning tool for mortar joints is an electric or air-chipping hammer with a chipping tool that is slightly smaller than the mortar joint as a way to prevent binding.

The technician removes all of the loose or powdering mortar, cleans the joint thoroughly with a wire brush, tamps down the joint with a plasterer’s brush, replaces the mortar with a mortar gun or small trowel, and smoothes the joint with a mason’s jointing tool.

A mortar mixture of 1:2:4 mortar, sand and water by volume is good for tuckpointing. The jointing tool smoothes the surface of the joint, bonds the mortar to the brick — which is especially important for the upper and lower edges of the adjoining brick or blocks — and shapes the joint to allow water to runoff more easily.

Care in this stage of the pointing job results in longer-lasting repairs. After the joint sets up, the technician sweeps it with a broom to remove excess mortar from the adjacent brick or block wall surfaces.

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  posted on 12/1/2008   Article Use Policy

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