TuckPointing Notes

To replace the mortar effectively, there are some particulars that affect the finished repair project on your brick.

Clearing Joints - Relieving Stress. Probably the core issue, when it comes to repointing, is safely and cleanly removing the old joints. To achieve this, a narrower joint cold chisel might be needed other than the actual joint width. To relieve or minimize joint stress as it is being removed, the central part of the joint should first be removed. Then any mortar stuck on the brick.

First determine and confine the exact lengths to be removed. Chisel an opening at one end, removing the mortar, angling the waste side of the chisel tip angle from one side to the other, while working toward a cone, carefully going deeper and deeper until a void is created. This will be an end point and the removal should progress toward an opening - since adding impact on the filled mortar is likelier to extend the failing joint with any under the surface unseen.

An alternative is an angle grinder fitted with a masonry blade. But beware, straightness and accuracy have to be applied to avoid miscuts into the brick faces.

Mortar Mixing / Bonding Agents. Mixing the mortar is not always a straightforward task. Although, additives can be mixed-in for stronger bonds based on your application, be cautious of the proper mixing ratios since too much water can actually prohibit a proper drying cycle.

Many recent applications can do with a straight commercial grade Type S mortar, where only water is added. Others require that the lime and cement be mixed seperately. Masonry suppliers can be indispensable when it comes to these formulations and they may want to see brick and mortar samples.

Options for mixing the mortar include: the hand trowel for smaller repeat batches, the mortar hoe, which is basically a hoe with holes in it, and the heavy duty mixing drill equipped with a paddle.

When mixing to desired consistency, track water amounts as you add with a measuring quart container to easily duplicate the same on future batches. Mix conservatively to start, perhaps a 1/2 gallon. Re-tempering the mix is normally not recommended.

Mortar Colorants. Mix colorants in measured tablespoon and even teaspoon quantities. Taking all precautions to avoid breathing, and skin and eye contact as some colorants are toxic.

Mix samples, and allow adequate time before comparing tests with clean mortar joints being matched.

Tooling Joints. "Half-round" jointer tools are available in different arcs to form concave joints (pictured above before residue cleaning). The double-end jointers are also available for 'V joints'. A raked joint is scraped out with a square pattern tool to about 1/4" to 3/4" depth, creating a shadow from the recess. The flush joint is scraped level with a trowel edge.

Brick Availability. Damaging bricks on joint removal can usually be avoided. But sometimes it is unavoidable. Focusing on the fact that some bricks are no longer available for replacement, the repointing process should take all efforts in protecting the existing bricks that are already in place.