Have you ever marvelled at the sturdiness and aesthetic appeal of Australia's double brick walls? These structural marvels aren't just a key feature in the country's heritage architecture; they also continue to be a popular choice in modern construction. Let's delve into the details, benefits, and considerations of exterior double brick walls, favoured by homeowners and architects alike.
Exterior double brick walls, as the name suggests, are made from two layers of bricks with a cavity in between. This cavity, which forms a crucial part of the wall detail, not only adds to its thermal efficiency but also serves as a space for services like plumbing and electrical wiring. The wall detail involves several components, including the bricks, mortar, cavity, ties, and insulation, each playing a significant role in the wall's performance and longevity.
Construction and Materials
The construction of exterior double brick walls begins with laying the outer and inner leaves of bricks with a bonded pattern. This pattern provides strength and stability to the wall. The gap between the leaves, typically around 90 to 100 mm, forms the cavity. The cavity is filled with air, providing insulation, and can also accommodate services.
Bricks are the primary material used in these walls. They can be made from clay or concrete, each offering unique advantages. Clay bricks, for instance, provide excellent thermal mass, while concrete bricks are more durable and resistant to moisture. The mortar used to bind the bricks can also affect the wall's performance. A mix of cement, sand, and water is most common, but additives can enhance the mortar's properties.
Bricks: Types and Properties
Clay bricks, fired in a kiln, are popular in Australia due to their thermal mass, which helps regulate indoor temperatures. They are also durable and resistant to fire. Concrete bricks, on the other hand, are made from a mix of cement and aggregates. They are highly resistant to moisture and chemicals, making them ideal for use in areas prone to moisture or with high salt content in the soil.
Interlocking or-fecta bricks can also be used. These bricks have interlocking edges, reducing the need for mortar. This not only speeds up construction but also makes the walls more permeable to water, helping to mitigate the risks of water damage.
Mortar Mix and Wall Detail
The mortar mix can significantly impact the wall's performance. A common mix consists of one part cement to five or six parts sand. Additives like air-entraining agents or water reducers can improve the mortar's workability or resistance to freezing and thawing. The mortar should also be designed to accommodate the wall's movement due to expansion and contraction.
The wall detail also involves the use of cavity ties. These ties connect the inner and outer leaves, providing stability and helping to manage the wall's movement. They are typically made of galvanised steel or composite materials and provide a space for services to pass through.
Advantages of Exterior Double Brick Walls
Exterior double brick walls offer numerous benefits, contributing to their enduring popularity in Australian construction. They provide excellent thermal mass, helping to maintain consistent indoor temperatures. The cavity also acts as a barrier against noise, reducing sound transmission into the home. This is particularly important in urban areas where noise pollution is a significant issue.
The cavity also provides a space for services, reducing the need to run pipes and wires externally. This not only makes the building's exterior neater but also protects services from damage. Double brick walls are also highly durable, providing excellent resistance to fire and moisture. They are also low maintenance, withstanding Australia's varied weather conditions with minimal deterioration.
Thermal Efficiency
Double brick walls excel in providing thermal comfort. The thermal mass of the bricks helps to absorb and store heat during the day, releasing it at night when temperatures drop. This helps to maintain a consistent indoor temperature, reducing the need for heating and cooling. The cavity also provides insulation, further enhancing the wall's thermal efficiency.
In fact, double brick walls are so effective at providing thermal comfort that they often meet or exceed the Australian Building Code's thermal performance requirements without the need for additional insulation. This can lead to significant savings on heating and cooling costs.
Noise Reduction and Soundproofing
Double brick walls also provide excellent sound insulation. The dense bricks and the air-filled cavity work together to absorb and dampen sound, reducing noise transmission into the home. This is particularly beneficial in urban areas with high levels of traffic noise or in multi-unit developments where privacy is a concern.
Exterior double brick walls can significantly reduce noise levels, creating a quieter, more comfortable living environment. This can have significant health benefits, as excessive noise has been linked to stress, sleep disturbances, and even cardiovascular disease.
A well-constructed exterior double brick wall is a testament to Australia's construction heritage. Their durability, thermal efficiency, and soundproofing capabilities make them an excellent choice for modern construction. Whether you're building a new home or renovating an old one, considering exterior double brick walls could be a solid, long-term investment in your property's future. Explore the possibilities with an experienced architect or builder today, and discover the benefits of this tried-and-true wall detail for yourself.