Contrary to popular belief, homes built of brick and mortar don’t last forever, and occasionally a repair job, such as tuck-pointing work may be needed. To keep your home in tip-top shape, it is important to be able to assess the condition of your exterior and to know a few basic repair techniques. In this article the situations that create the need for tuck-pointing are discussed as well as how to do your how tuck-point repairs.
Old Mortars and Portland Cement:
Some old mortars have Portland cement in them and use animal hairs as a binder. Portland cement is made by burning a mixture of limestone and clay in a kiln. This mix helps to hold the bricks firmly in place.
Old mortars eventually break down and lose their ability to adhere to brick. Water can get behind brick due to poor flashing installation or structural damage to the roof. The brick and mortar absorb the water, and as the wall dries out the bricks chip and the mortar pops out. Before beginning repairs to masonry, locate the cause of the damage and eliminate it.
Tuckpointing consists of chipping out old, damaged mortar and replacing it with new mortar. Spring and fall are the best seasons for this work because temperatures of around 70 degrees are ideal for curing mortar mix. This is particularly important, as mortar that freezes before curing becomes brittle.
Tools for Tuckpointing
Two job-specific tools are required for the work: a masonry chisel and and a small trowel. Any masonry chisel that will fit into the mortar joint will do, but a plugging chisel is specifically designed for such work. A hammer, a soft brush, and a drop-cloth are also necessary.
How to Tuckpoint
The mortar joint should be chiseled out to a depth of ½ to ¾ inch. Hold the chisel at an angle and strike the end firmly with a hammer. Be sure to wear safety goggles when chiseling out the mortar joint. Work on removing inch-long pieces of mortar and try to chisel so that there is a rectangular groove in the mortar joint. Use a soft brush to clean out all loose particles and dust them out of the joint.
The mortar used for tuckpointing is a sand mix and only the amount able to be used in one-hour’s time should be mixed. Add water slowly, until the mortar is the consistency of cottage cheese.
Put a trowel on a small board. Hold the board under the joint to be pointed and push some mortar mix into the joint with the trowel making sure that there are no empty spaces. Let the mortar dry until a thumb can leave a distinct impression in it. Use the tip of the trowel along each of the mortar joints that have been re-pointed to smooth the mortar. When the mortar has set enough to prevent smearing, brush off any loose particles.
After the mortar has cured for two weeks, scrape off any remaining particles with a masonry chisel and then scrub the wall with water and a stiff brush.
Always work safely.