Pointing is an essential process in masonry construction, specifically in the finishing of mortar joints between bricks or stones. It involves implementing joints with a depth of 10–20 mm and filling them with high-quality mortar to create a specified shape and style. Pointing is crucial not only for structural integrity but also for aesthetic value, especially in exposed masonry work, as joints are often the weakest spots where rainwater or dampness can penetrate.
In this article, we will explore the materials, preparation process, different types of pointing, and how each can enhance the durability and appearance of masonry construction.
Materials Used in Pointing
Mortar Types for Pointing Work
- Lime Mortar (1:2) – This mix includes one part fat lime and two parts sand or surkhi (a powdered burnt clay). Lime mortar is often used in older or historic buildings where lime-based materials provide flexibility and compatibility with original construction.
- Cement Mortar (1:3) – Made of one part cement and three parts sand, cement mortar is more commonly used in modern construction. Its strength and durability make it ideal for pointing in areas prone to moisture or where a strong bond is required.
Preparation of the Surface for Pointing
To ensure a strong and durable finish, the surface must be prepared carefully before applying the mortar. Here are the key steps:
- Raking Joints: All joints are raked down to a depth of 20 mm while the mortar is still soft. This creates a cavity for the fresh mortar to bond with the masonry securely.
- Cleaning and Wetting: Both the joints and the surface are thoroughly cleaned to remove dust and debris. The cleaned surface is then wetted to improve mortar adhesion, preventing it from drying out too quickly once applied.
Pointing Process
After preparing the surface, the actual pointing process begins. Mortar is carefully placed in the joints with a small trowel, ensuring it is pressed firmly to form a strong bond with the existing mortar in the cavity. Care is taken, especially in high-quality masonry work like ashlar or first-class brickwork, to prevent the mortar from covering the face edges, which could detract from the masonry’s appearance. Once applied, the pointed surface is kept wet for at least a week, allowing the mortar to cure fully and set.
Types of Pointing in Masonry
Pointing styles vary in both function and appearance. Here’s an overview of the most common types:
- Flush Pointing Flush pointing involves pressing the mortar flush with the masonry edges, creating a smooth finish with neatly trimmed edges. While it may lack decorative appeal, flush pointing is highly durable because it doesn’t allow space for dust or water to settle. Its strength and resistance to weathering make it one of the most widely used pointing methods.
- Recessed Pointing In recessed pointing, the mortar is pressed back by at least 5 mm from the edges, creating a vertical face. This type of pointing provides a clean, distinctive look, enhancing the overall appearance of the masonry by adding depth to the joints.
- Beaded Pointing Beaded pointing is formed by creating a concave edge in the mortar joint using a steel or iron tool. While it gives a visually appealing finish, it is more susceptible to damage than other types, as the concave bead can wear down or chip over time.
- Struck Pointing Struck pointing is a variation of flush pointing where the face is inclined, with the upper edge recessed by about 10 mm. This angle allows for efficient water drainage, reducing the risk of water penetration and making it suitable for areas prone to heavy rainfall.
- Rubbed, Keyed, or Grooved Pointing This is another modification of flush pointing, where a groove is formed along the midpoint of the joint using a pointing tool. The added groove gives a decorative look, adding both texture and dimension to the masonry.
- Tuck Pointing In tuck pointing, mortar is pressed into the raked joint, finishing flush with the face. Before the mortar sets, a narrow channel is cut into the center, which is then filled with white cement putty. This putty is allowed to project slightly beyond the joint face, creating a striking contrast. If the projection is done using mortar rather than putty, it is referred to as bastard pointing or half tuck pointing.
- V-Pointing V-pointing is achieved by creating a V-shaped groove in the flush-finished surface. This type of pointing provides a unique visual style that can enhance the architectural character of a building.
- Weathered Pointing Weathered pointing involves creating a V-shaped projection that helps direct water away from the joint. This projection is particularly useful in climates with frequent rain, as it minimizes water infiltration and reduces the risk of dampness.
Pointing plays a crucial role in both the functionality and appearance of brick and stone masonry. Each pointing type serves specific purposes, from improving water drainage to enhancing visual appeal. By choosing the appropriate type of pointing based on structural needs and aesthetic preferences, builders and masons can ensure that masonry construction remains durable, weather-resistant, and visually striking for years to come. Proper preparation, the right mortar mix, and attention to detail in application are key to effective pointing, making it a vital aspect of high-quality masonry work.