The type of mortar commonly used for bricklaying depends on factors such as the structural requirements of the project, environmental conditions, and local building codes. However, two of the most commonly used types of mortar for bricklaying are Type N mortar and Type S mortar:

1. **Type N mortar**:
- Type N mortar is a general-purpose mortar suitable for most standard bricklaying applications.
- It is composed of Portland cement, hydrated lime, and sand in a ratio of 1:1:6 (cement-lime-sand) by volume.
- Type N mortar provides good bond strength and flexibility, making it suitable for use in non-load-bearing walls, interior walls, and above-grade exterior walls.
- It offers a good balance of strength, workability, and weather resistance, making it versatile for a wide range of construction projects.

2. **Type S mortar**:
- Type S mortar is a stronger and more durable mortar compared to Type N mortar.
- It is composed of Portland cement, hydrated lime, and sand in a ratio of 1:1:4 (cement-lime-sand) by volume.
- Type S mortar has higher compressive strength and bond strength than Type N mortar, making it suitable for use in load-bearing walls, below-grade applications, and areas with high wind or seismic activity.
- It provides greater resistance to water penetration, freeze-thaw cycles, and other environmental factors, making it ideal for exterior masonry construction in harsh climates.

Both Type N and Type S mortars are commonly used in residential and commercial construction for bricklaying, depending on the specific requirements of the project. It's important to consult local building codes and specifications to determine the appropriate type of mortar for your particular application and ensure compliance with regulatory standards. Additionally, mortar mixes can be customized or modified with additives to meet specific performance requirements or address unique project conditions.