Brick pointing (sometimes referred to as tuckpointing or repointing) encompasses various techniques to restore, repair, or replace deteriorating mortar joints in masonry construction. While spot pointing focuses on a specific area, sometimes repointing an entire building may be in order. Here, we’re bringing you inside the repointing process for a deeper understanding.
Why brick pointing?
Over time, weathering and decay may cause voids in the mortar joints between brick masonry units, allowing an ingress of water. By ignoring the situation, the entering water can cause significant damage through the freeze/thaw cycle and salt dissolution and deposition.
The repointing process begins with the most critical step, removing damaged mortar to a depth equal to or slightly more than the joint’s width. Depending on the depth, several passes may be required, allowing the mortar to cure for at least 24 hours. It’s crucial to create the joint profile as rectangular as possible, so the new pointing mortar has ample opportunity to bond with the masonry unit. Please note, although a common practice, sound mortar generally doesn’t require removal during the repointing process.
To avoid damage to masonry units, removing old mortar must occur. However, this process based on an individual basis. Structures with softer materials, such as under-fired brick, often require hand removal of the mortar. However, Portland cement can be removed with a grinder or power circular masonry blade. Mortar removal from vertical joints typically occurs by hand or with small power chisels.
Novice repointing opens the door for several issues. Often, the work raises the mortar joint above the face of the masonry unit. The rise then causes the mortar edge to feather. Not only is the result aesthetically undesirable, but it can also cause erosion problems. Furthermore, depending on the mortar’s nature, the mortar that rises above the level of the masonry face can damage the corner of the masonry unit. In these cases, deteriorated mortar has generally not been removed to a sufficient depth.
Selecting mortar for brick pointing.
When repointing, it’s crucial to utilize like types of mortar. Comparing characteristics to the original mortar ensures compatibility. Items to consider include:
- Compressive strength
- Thermal expansion
For instance, if the original building processes used a soft lime-based mortar, the most appropriate repointing material will contain a significant amount of lime. Another critical item to note is the use of Portland cement mortar in older, soft masonry units often leads to severe damage because of physical incompatibilities. When in doubt, mortar analysis with an architectural engineering firm allows for trustworthy recommendations for mortar replacement compatibility.
Brick pointing, although a common practice, is relatively complicated in the details. Thus, the process is best left to experienced professionals.
For more information, contact the experts at Abbot Building and Restoration. For nearly a century, Abbot has remained committed to providing effective single-source solutions, quality workmanship, the highest safety levels, and devotion to exceptional customer service. Contact Abbot Building and Restoration today by calling (617) 445-0274, and be confident that your project in the hands of the experts.