wall ties for cavity walls

Wall Ties for Cavity Walls An Overview

Cavity walls are a popular construction method, especially in modern residential and commercial buildings. They consist of two separate wall sections, or leaves, with a space, known as the cavity, in between. This design provides numerous advantages such as improved thermal insulation, moisture control, and increased structural stability. Wall ties play a crucial role in cavity wall construction, serving as a key component that connects the two leaves while allowing for slight movement and drainage of any moisture that may enter.

What are Wall Ties?

Wall ties are metal fasteners, typically made from stainless steel, galvanized steel, or plastic, that are installed to connect the inner and outer leaves of a cavity wall. Their primary function is to provide structural stability, ensuring that the two leaves work together effectively and maintaining the integrity of the wall system. Wall ties also help to prevent the outer leaf from being blown away by wind pressure and contribute to the overall load-bearing capacity of the wall.

Types of Wall Ties

Several types of wall ties are available on the market, each suited for different applications and conditions. The most common types include

1. Double-Skin Wall Ties These ties are used to connect two leaves made from materials like brick, stone, or concrete. They are designed to handle lateral loads and are essential in ensuring the overall stability of the wall.

2. Cavity Wall Ties Specifically designed for cavity walls, these ties come in various shapes and lengths. They typically feature a flexible design, allowing for movement due to building settlement or thermal expansion.

3. Non-Expansion Ties As the name suggests, these ties do not allow for any movement once installed. They are suitable for specific conditions where minimal movement is expected.

4. Expansion Wall Ties These ties accommodate movement and can expand or contract with changes in temperature or moisture levels. They are ideal for environments subject to significant thermal changes.

Installation of Wall Ties

The correct installation of wall ties is critical for their performance. Ties should be installed at regular intervals, typically every 600mm in height and 900mm in length, to ensure an even distribution of forces across the wall. They should be fixed into both leaves of the wall, with a minimum embedment into the inner leaf to ensure secure anchoring.

Additionally, wall ties should be placed at a height that allows for proper drainage of moisture that may enter the cavity. It is essential for the outer leaf to be adequately protected against weather elements and for the ties to be spaced correctly to prevent any thermal bridging, which can compromise insulation performance.

Importance of Wall Ties

The importance of wall ties in cavity wall construction cannot be understated. They serve as essential components that enhance the building's safety and performance. Properly installed wall ties contribute to preventing structural issues, such as bowing or bulging of the outer leaf, which can lead to significant repair costs and safety hazards.

Furthermore, wall ties play a critical role in moisture management. By allowing for drainage within the cavity, they help prevent water accumulation, which can lead to dampness and mold growth within the building. This is especially crucial in climates where rain and snow are prevalent, as water ingress can severely affect indoor air quality and occupant comfort.

Conclusion

In conclusion, wall ties are an indispensable aspect of cavity wall construction, providing vital support and ensuring the structural integrity of buildings. With various types and installation methods available, it is essential for builders and architects to understand the specific requirements of their projects. By prioritizing the proper use and placement of wall ties, construction professionals can significantly enhance the durability, safety, and efficiency of cavity walls, leading to long-lasting and resilient structures.