Brick masonry is an essential part of construction, providing both structural support and aesthetic appeal to buildings. Ensuring quality in brick masonry requires adherence to specific practices that address accuracy, appearance, durability, structural performance, weatherproofing, thermal performance, and movement accommodation. This article outlines key recommendations to ensure a high standard in brick masonry construction.
1. Accuracy and Tolerances
Achieving accuracy in brick masonry is essential for maintaining structural integrity and aesthetic consistency. Before beginning, it’s crucial to set standards for alignment with structural frames, openings, and adjacent elements. Checking lines and levels before laying bricks is highly recommended, especially in areas demanding high precision. For critical sections, laying two dry courses of bricks can minimize cutting, allowing better alignment with openings and reducing the need for later adjustments.
2. Appearance
The aesthetic quality of brick masonry largely depends on the skilled placement of bricks. Due to size variations in clay bricks, maintaining uniform perps and bed joints can be challenging. For those requiring enhanced visual accuracy, concrete bricks may be a better choice. One effective technique is plumbing every fifth perpend to create a visually pleasing, consistent appearance along the brickwork’s height. Additionally, keeping the brickwork clean as construction progresses prevents unwanted marks and debris accumulation. Protecting the work from rain, frost, and physical impacts by using boards or other barriers is essential, as exposure can negatively impact appearance. For projects where standard cleaning methods are insufficient, acid cleaning may be used cautiously and thoroughly rinsed with water to avoid damage.
3. Durability
Brick durability is crucial, especially in areas exposed to the elements. Choosing bricks suitable for the expected exposure levels is essential for longevity. Mortar strength should align with the brick’s strength, as mismatched materials may result in cracking. Proper curing of mortar is also necessary to reach desired strength levels and should be protected from frost. Using insulating materials under waterproof covers can prevent frost damage during curing, ensuring the wall’s strength and stability over time.
4. Structural Performance
Structural performance in brick masonry relies on proper support and restraint installation, including footings, lintels, shelf angles, wind posts, and cavity wall ties. Following manufacturer guidelines and building codes for these elements is critical. To avoid structural compromise, the rate of laying bricks should not exceed 1.5 meters per day. Using solid cross joints instead of smaller mortar dabs strengthens the brickwork, even if it requires more time and material. Shelf angles should cover at least two-thirds of the brick width for adequate load bearing. Cavity wall ties, although small, play a significant role by connecting walls and ensuring they function cohesively. Without proper ties, adjacent walls may work independently, undermining structural integrity.
5. Weather-Tightness
Weatherproofing an exterior wall depends on the cavity’s role as a barrier to water ingress. Mortar droppings and protrusions in the cavity can impede effectiveness, so keeping the cavity clean is essential. Partial or fully filled cavities are recommended to achieve effective thermal insulation. Following manufacturer guidelines for cavity wall construction can prevent issues with weatherproofing. Fully filled bed and cross joints are also critical to maintain weather-tightness, as unfilled joints can allow moisture penetration, compromising the masonry.
6. Thermal Performance
Proper thermal insulation prevents heat loss and ensures energy efficiency in brick masonry. It’s vital to prevent gaps in insulation layers, ensuring they are as dry as possible before and after installation. For buildings requiring high thermal insulation, fully filled cavity walls are the preferred option. To reach optimal thermal performance, follow specific installation instructions from manufacturers, which can also help prevent capillary water movement through joints—a common challenge in fully filled cavities.
7. Movement Accommodation
Brick masonry expands and contracts with temperature changes, requiring proper accommodation of movement to prevent cracks. Providing movement joints at appropriate intervals can absorb this expansion, preventing stress in the wall. Compressible materials should be used in these joints to facilitate movement, and masons should be well-informed about joint locations and specifications before construction begins, allowing for smooth integration during the masonry process.
8. Holes and Chases
Holes for pipes, cables, or other services can disrupt brickwork and pose a challenge to subcontractors. Detailed drawings showing the locations of these holes can streamline the process and help avoid delays caused by last-minute changes. By planning early, contractors can ensure a more efficient, organized workflow, minimizing disruptions to the masonry structure.
9. Lead Flashings
In some cases, lead flashing may need to be installed beneath the damp-proof course. To do this effectively, introduce a clean rebate in the brickwork or a wider bed joint incorporating a timber lath that aligns with the brick face. This method ensures the flashing is securely in place, protecting against moisture infiltration and improving the masonry’s overall longevity.
Conclusion
High-quality brick masonry construction relies on meticulous planning and careful execution across various aspects, from ensuring accurate placement to addressing structural and environmental factors. Following these best practices in site brick masonry construction will help produce durable, visually appealing, and thermally efficient brickwork. By focusing on these recommendations, builders can deliver masonry walls that stand the test of time, meeting both aesthetic and functional demands.