Wall Ties for Cavity Walls Installation and Best Practices Guide

Wall Ties for Cavity Walls Importance, Types, and Best Practices

Cavity walls have become a prevalent construction method due to their efficiency in providing thermal insulation and moisture control. These walls consist of two separate masonry leaves with a space or cavity between them. While they are highly effective in improving building performance, the use of wall ties is crucial for their structural integrity. This article discusses the importance of wall ties for cavity walls, the different types available, and best practices for their installation.

Importance of Wall Ties

Wall ties serve as connectors between the inner and outer leaves of a cavity wall. Their primary function is to provide lateral support and prevent the outer leaf from moving independently of the inner leaf, particularly under the influence of wind loads or other lateral forces. Additionally, wall ties help transfer loads from the outer wall to the inner wall, ensuring that both leaves act together as a single structural unit.

Another key role of wall ties is to facilitate the movement of moisture and vapour management within the cavity. Properly installed wall ties can help to mitigate the risk of condensation by allowing air to circulate within the cavity, thus maintaining the building’s overall integrity and reducing the likelihood of damp issues.

Types of Wall Ties

There are several types of wall ties utilized in cavity wall construction, each designed to meet specific needs based on the environment and structural requirements. The most common types include

1. Stainless Steel Wall Ties These ties are preferred for their corrosion resistance, making them ideal for coastal areas or locations with high levels of moisture. Stainless steel ties ensure long-lasting performance without compromising structural safety.

2. Galvanized Steel Wall Ties While they are less expensive than stainless steel ties, galvanized steel ties are coated to enhance corrosion resistance. However, their lifespan can be curtailed in highly corrosive environments.

3. Plastic Wall Ties These ties are lighter and resistant to corrosion but are generally used for low-rise structures. They provide excellent thermal insulation and can help reduce thermal bridging.

4. Ancor Wall Ties These are often used in situations where feedback from the site indicates a higher risk of movement, as they offer additional flexibility and adaptability.

Best Practices for Installation

To ensure optimal performance of wall ties, adherence to best practices during installation is critical

- Spacing The spacing of wall ties should be determined according to building regulations and specific structural considerations. Generally, ties should be installed every 600 mm vertically and every 900 mm horizontally, but this may vary based on local codes.

- Height Wall ties should be installed at the appropriate height, typically at the level of the structural floor and within 225 mm of the top of each cavity.

- Orientation and Installation Wall ties should be oriented correctly, with the ties installed at an angle or with the correct orientation to allow for moisture drainage.

- Regular Inspection Regular inspections of wall ties should be conducted to check for corrosion or damage, particularly in older buildings, as the integrity of the wall ties is crucial to the structural safety of the cavity walls.

In conclusion, wall ties are an essential component of cavity walls that contribute significantly to their stability, performance, and longevity. By understanding their importance, types, and proper installation practices, builders and homeowners can ensure the durability and safety of their structures.