The type of cement used for pointing depends on the specific application and desired outcome. However, mortar is the most common material used for pointing, typically composed of a mixture of cement, sand, and water.
Here's a breakdown of common cement types used in pointing:
1. Portland Cement Mortar
Portland cement is the most widely used type of cement for general construction, including pointing. It's known for its strength and durability.
Portland cement mortar is a versatile choice for pointing various types of masonry, from brick to stone. It's available in different grades, each with specific properties:
* **Type I:** General-purpose cement suitable for most pointing applications.
* **Type II:** Moderate sulfate resistance, making it ideal for pointing in areas with potential sulfate exposure.
* **Type III:** High early strength, suitable for pointing when rapid hardening is required.
* **Type IV:** Low heat of hydration, ideal for massive concrete structures, although less common for pointing.
* **Type V:** High sulfate resistance, ideal for pointing in areas with high sulfate concentrations.2. Masonry Cement Mortar
Masonry cement is a pre-blended mix of Portland cement, lime, and other additives designed specifically for masonry applications, including pointing.
Masonry cement offers several advantages over traditional Portland cement mortar:
* **Improved workability:** Easier to mix and apply, resulting in a smoother finish.
* **Increased water retention:** Helps prevent cracking and shrinkage during curing.
* **Enhanced color stability:** Less prone to discoloration over time.3. Lime Mortar
Lime mortar is a traditional pointing material consisting of hydrated lime and sand.
Lime mortar offers unique advantages:
* **Breathability:** Allows moisture to pass through, preventing trapped moisture and potential damage to the masonry.
* **Flexibility:** Can accommodate slight movement in the masonry, reducing the risk of cracking.
* **Aesthetic appeal:** Provides a softer, more traditional look compared to cement mortar.4. Specialised Pointing Mortars
For specific applications or desired properties, specialized pointing mortars are available:
* **Colored mortars:** Offer a wide range of colors to match or complement the masonry.
* **Water-repellent mortars:** Enhance the water resistance of the pointing, protecting the masonry from moisture damage.
* **High-performance mortars:** Designed for challenging environments, such as areas with high traffic or extreme weather conditions.The choice of cement for pointing depends on factors like the type of masonry, the environment, and the desired aesthetic and performance characteristics.
