Wall ties are crucial components in cavity wall construction, providing essential structural integrity by connecting the inner and outer leaves of masonry. As building techniques have evolved, so too have the materials used to manufacture these vital elements.
Understanding the materials used in wall ties is essential for architects, builders, and property owners alike. The choice of material directly impacts the longevity, durability, and performance of cavity wall structures.
Modern Materials for Wall Ties
Stainless Steel
Today, stainless steel, particularly Grade 304, dominates the wall tie market. Its superior corrosion resistance and durability make it the material of choice for most cavity wall constructions. Stainless steel ties offer a maintenance-free life, significantly reducing long-term costs and enhancing building longevity.
The value-engineered design of stainless steel ties optimises material usage without compromising strength. This efficient use of resources contributes to both cost-effectiveness and sustainability in construction practices.
Galvanised Steel
Despite the prevalence of stainless steel, galvanised steel still finds applications in certain construction scenarios. Modern galvanisation techniques have improved the corrosion resistance of these ties, making them suitable for less demanding environments or shorter-term structures.
However, it's crucial to note that galvanised steel ties still fall short of stainless steel in terms of longevity and corrosion resistance. Their use should be carefully considered based on the specific requirements of each project.
Composite Materials
In recent years, innovative composite materials have entered the wall tie market, catering to specialised construction needs. One notable example is the use of pultruded basalt fibres set in a resin matrix, such as those found in Ancon's Teplo range.
These composite ties excel in ultra-low energy construction, where thermal bridging is a critical concern. Their low thermal conductivity helps maintain the energy efficiency of highly insulated cavity walls, making them ideal for passive house designs and other energy-conscious building projects.
Design and Features of Modern Wall Ties
Contemporary wall ties incorporate design elements that enhance their functionality and durability. A key feature is the drip formation, strategically placed to prevent water passage from the outer leaf to the inner leaf of the cavity wall. This design element is crucial in maintaining the water-resistant properties of the cavity wall system.
The effectiveness of wall ties heavily depends on proper installation. Correct positioning and embedment in mortar are essential to ensure the ties perform their intended function of binding the two leaves of the cavity wall together.
Selection and Installation Guidelines
Choosing the appropriate wall tie involves considering several factors:
- Type of masonry: Different masonry materials may require specific tie designs for optimal performance.
- Cavity width: The length of the tie must accommodate the cavity width while providing sufficient embedment in both leaves.
- Building height: Taller structures may require stronger ties to withstand increased wind loads.
- Geographical location: Coastal areas or regions with harsh weather conditions may necessitate more corrosion-resistant materials.
For effective installation, wall ties should be:
- Pressed down into fresh mortar to ensure proper embedment.
- Surrounded by mortar on all sides to prevent water ingress.
- Installed with a slight fall towards the outer leaf to direct any moisture away from the inner leaf.
Adhering to these guidelines ensures that wall ties effectively bind the cavity wall leaves together while maintaining the wall's water-resistant properties.
FAQs
Here are our most frequently asked questions regarding wall tie material:
Q: What materials were historically used for wall ties?
A: Historically, wall ties were made from wrought or cast iron. These materials were heavy and prone to corrosion, leading to structural issues over time. Later, galvanised mild steel was introduced, offering improved corrosion resistance but still limited to about 15-20 years of effective use.
Q: Why is stainless steel now the preferred material for wall ties?
A: Stainless steel, particularly Grade 304, is favoured for its superior corrosion resistance, durability, and maintenance-free lifespan. It offers long-term structural integrity without the need for replacement, making it cost-effective over the building's lifetime.
Q: What factors influence the selection of wall tie materials?
A: The choice of wall tie material depends on several factors, including the type of masonry, cavity width, building height, geographical location, and environmental conditions. Regulatory requirements and specific project needs also play a role in material selection.
Q: Are there specific regulations governing wall tie selection in the UK?
A: Yes, wall tie selection in the UK is governed by Eurocodes, Building Regulations, and additional documents such as PD 6697:2010. These guidelines ensure that appropriate materials and designs are used for different construction scenarios.
Q: How should wall ties be installed for optimal performance?
A: Wall ties should be pressed down into fresh mortar, ensuring they are fully surrounded by mortar. They should be installed with a slight fall towards the outer leaf to prevent moisture transfer. Proper spacing and alignment are crucial for structural integrity.
Q: Can wall ties be used in different types of cavity wall constructions?
A: Yes, wall ties are versatile and can be used in various cavity wall constructions, including masonry-to-masonry and masonry-to-timber applications. Different designs may be required for specific construction types.
Get in touch with our team
Have more questions about wall ties? We can offer a wealth of advice and support - get in touch with us at 01639 790426 or 07852 229017 or by filling in our online contact form. We provide our services throughout South Wales, Swansea, Cardiff, Bristol, and nearby areas.
