Low Thermal Conductivity Ties: Maximising Energy Efficiency in Modern Construction
In an era where energy efficiency and environmental responsibility are at the forefront of construction priorities, even the smallest detail can make a significant difference. Traditionally, wall ties have been selected mainly for their structural qualities—strength, corrosion resistance, and compliance with wind load requirements. However, as UK Building Regulations push for more efficient building envelopes, reducing heat transfer across the cavity has become equally important. Low thermal conductivity ties, sometimes known as low- or ultra-low-thermal-bridge ties, have emerged as a solution to minimise heat loss through masonry walls.
This article delves into the role of these specialised ties, explaining how they help satisfy energy regulations and enhance occupant comfort. If you are new to the subject of wall ties, you may wish to start with our hub piece, “The Ultimate Guide to Wall Ties: Types, Applications, and Installation Best Practices,” which covers the fundamentals of wall tie selection and placement. Once you understand those principles, you can discover how low thermal conductivity ties fit into an overall strategy for creating high-performance, cost-effective buildings.
1. Understanding Thermal Bridging in Masonry Construction
Thermal bridging occurs whenever there is a path of higher conductivity through the building envelope that allows heat to flow more readily from inside to outside. Common culprits include metal components such as steel beams, window frames, and, of course, wall ties. In standard cavity wall construction, ties span the gap between the inner and outer leaves, potentially providing a route for heat to bypass insulation. While each tie individually may transfer only a small amount of heat, a large number of ties across an entire building can create a noticeable cumulative effect.
The consequences of thermal bridging extend beyond higher energy bills. Condensation can occur when warm interior air meets cold spots in the wall, leading to damp patches, mould growth, or even structural decay over the long term. By minimising thermal bridging, designers and builders can meet strict U-value targets, lower heating demand, and reduce the risk of condensation-related issues.
2. The Role of Wall Ties in Thermal Performance
Wall ties are critical for bonding two leaves of masonry or connecting masonry to a backing structure. However, their metal composition—often stainless steel—can create a thermal pathway. Stainless steel is an excellent choice for corrosion resistance and structural strength, yet it still conducts heat more effectively than non-metallic materials.
Conventional ties are necessary for many builds, especially where high structural loads or challenging conditions demand robustness. In these instances, specifying a tie with the lowest feasible cross-sectional area can reduce thermal bridging to some degree. However, for projects aiming for superior energy performance—like Passivhaus or zero-carbon homes—low thermal conductivity ties go a step further. They are engineered to achieve minimal heat transfer while still providing the stability and durability that a masonry wall requires.
3. Materials and Design of Low Thermal Conductivity Ties
Instead of relying solely on stainless steel, low thermal conductivity ties commonly incorporate advanced materials or specialised geometries that reduce heat flow. There are several design approaches:
Composite Materials
Some manufacturers use a combination of stainless steel and polymers or ceramic-like composites. The steel portions may be strategically placed only where needed for structural anchorage, while the less conductive material bridges the gap between leaves.
Additional Coatings
Some ties include special coatings that diminish thermal transfer. Although coatings can help, they are typically not as effective as using intrinsically low-conductivity materials.
Despite these innovations, the ties must continue to meet the minimum strength requirements set out by British Standards and building regulations. This combination of mechanical performance and thermal efficiency often involves advanced manufacturing processes and rigorous testing. When browsing products, look for a reputable brand with CE or UKCA marking and documented thermal conductivity data.
4. Energy Savings and Meeting UK Building Regulations
Changes in the UK Building Regulations have placed greater emphasis on lowering the overall U-value of external walls and other envelope elements. These regulations, alongside programmes like the Standard Assessment Procedure (SAP) for dwellings, assess the thermal performance of various construction components.
By integrating low thermal conductivity ties, you can lower the effective U-value of a cavity wall. In some cases, this can be enough to offset other design constraints—perhaps enabling you to use a slightly thinner insulation layer or choose a particular wall finish. Even if the ties themselves represent a modest portion of a building’s heat loss, every incremental reduction can be critical in meeting stringent energy targets or sustainability certifications.
Additionally, improved thermal performance is not just about compliance. Reducing energy consumption has tangible benefits for end users. They can enjoy lower heating bills, a more comfortable living or working environment, and potentially improved indoor air quality if condensation is minimised. For developers, marketing properties as exceptionally energy efficient can provide a competitive edge in an increasingly eco-conscious market.
5. Installation Best Practices for Low Thermal Conductivity Ties
Although these ties differ in composition or profile from standard ties, many of the standard installation principles still apply:
Correct Embedment Depth
Ensure that both ends of the tie have adequate embedment in the mortar. Typically, this ranges from 50 mm to 75 mm, though manufacturer guidelines will specify exact distances. Under- or over-embedment can undermine both structural and thermal performance.
Spacing and Density
Follow project specifications and local regulations regarding tie density. While fewer ties can mean less thermal bridging, you must not compromise structural integrity or fail to meet the minimum requirements set out in Approved Document A or NHBC guidance.
Orientation
As with any wall tie, the drip feature should be positioned within the cavity, angled slightly downward towards the external leaf to prevent water crossing to the inner leaf. If the tie has a composite or shaped design, install it in the orientation recommended by the manufacturer.
Cleanliness in the Cavity
A significant build-up of mortar droppings can compromise the tie’s geometry, especially if the low thermal conductivity portion is delicate. Keeping the cavity clear remains a key site practice.
Compatibility Checks
Before specifying a particular tie, verify that it is compatible with your chosen insulation thickness and type. If the tie includes integrated insulation clips or washers, confirm they work with the brand and form of insulation you are using.
6. Comparison with Standard Stainless Steel Ties
The choice between a traditional stainless steel tie and a low thermal conductivity one depends on your project’s priorities:
Structural Load Requirements
Conventional ties may offer higher load ratings for large commercial or multi-storey buildings in very exposed areas. However, many low thermal conductivity ties also achieve Type 1 or Type 2 performance levels, so it is always worth checking the product specifications.
Thermal Objectives
If hitting certain U-values is vital, or you are aiming for an ultra-low-energy build, choosing low thermal conductivity ties can help you gain a few more points on SAP or adhere to Passivhaus guidelines.
Cost Considerations
Low thermal conductivity ties often cost more than standard alternatives due to the advanced materials and manufacturing processes. If your project budget is tight, you must weigh the long-term energy savings and compliance benefits against initial outlay.
Appearance and Handling
Although most ties are hidden within the wall, the shape or materials of low thermal conductivity ties can affect on-site handling. Some installers find certain designs slightly more challenging to set in mortar. Proper training or guidance can alleviate these minor hurdles.
7. Achieving Long-Term Durability
A common concern with any tie that strays from the traditional stainless steel model is durability. However, reputable manufacturers typically test their products extensively for corrosion resistance and structural longevity. Many advanced composite materials show excellent resilience in harsh or damp conditions. Stainless steel components or coatings often remain part of the design, ensuring the ties hold up over decades of use.
Checking warranties and performance certificates from manufacturers is advisable. Some may offer design life guarantees that mirror those of standard ties, so you can be confident that choosing a thermally efficient option does not compromise the long-term stability of the building.
8. Connecting Low Thermal Conductivity Ties with Other Components
The performance of a cavity wall system does not hinge on ties alone. A successful strategy for energy efficiency relies on a holistic approach:
Damp Proof Course (DPC)
Ensuring that your DPC is correctly installed and aligned with the tie’s drip features will help prevent damp bridging. If you want to learn more about how a DPC fits into a moisture-control strategy, our “Complete Guide to Damp Proof Courses (DPC): Materials, Installation, and Regulations” provides a detailed explanation.
Weep Holes
Paired with a well-designed DPC, weep holes allow water to escape from the cavity. If you need guidance on selecting or installing weep holes, our “Weep Holes” hub discusses ways to avoid moisture build-up that can undermine both insulation and structural components.
Fire Socks and Barriers
Maintaining the insulation’s integrity is crucial, and installing fire socks in cavities can sometimes be a requirement to slow fire spread between storeys or flats. Our “Fire Socks & Barriers 101” hub explains how these protective measures fit alongside other building envelope considerations.
Movement Ties
For projects susceptible to significant expansion or contraction, consider pairing low thermal conductivity ties with a system of movement ties to manage structural shifts without introducing cold bridging. “Movement Ties 101: Managing Expansion and Contraction in Masonry Walls” offers insights on best practices for accommodating movement in brickwork.
By carefully coordinating all these elements—DPC, insulation, weep holes, and barrier systems—you ensure that the benefits of low thermal conductivity ties are fully realised.
9. Where to Source Low Thermal Conductivity Ties
At Spechunter, we offer a diverse range of wall ties, including both standard stainless steel options and innovative low thermal conductivity models. Our stock, drawn from leading manufacturers, helps you meet structural and thermal performance requirements without compromising on compliance or build quality. If you are unsure which tie is best suited to your project’s environmental conditions, design load, or energy targets, our expert team can provide guidance.
We also pride ourselves on quick lead times, often offering next working day delivery on orders placed before midday, thanks to our two strategically located warehouses. To review our range or request a quote, visit our wall ties page. You can filter your search by brand, tie type, and other specifications to locate the perfect solution for your build.
Rounding Up
Low thermal conductivity ties are a natural evolution of wall tie technology. By incorporating special materials or reduced metal cross-sections, these products address the pressing need to minimise heat loss in contemporary building design. The result is a more energy-efficient envelope that remains structurally sound, meeting or exceeding the rigorous standards laid out in UK Building Regulations.
Whether you are designing a cutting-edge eco-home, refurbishing an existing property to modern efficiency standards, or developing multi-residential housing with ambitious thermal targets, specifying low thermal conductivity ties can prove a worthwhile investment. They reduce thermal bridging, lower energy costs, and enhance occupant comfort—all while maintaining the structural bonding that wall ties have traditionally provided.
If you are ready to explore specific options or if you need tailored advice on integrating these ties into a larger energy efficiency strategy, Spechunter is here to help. Our technical team can guide you to the right products, provide timely delivery, and ensure that your project achieves both robust structural performance and noteworthy energy savings. In tandem with strategies like effective DPC placement, well-installed weep holes, and appropriate fire barriers, low thermal conductivity ties form part of a holistic approach to building envelopes in the 21st century.