Movement Ties 101: Managing Expansion and Contraction in Masonry Walls
Masonry is a time-tested and durable building material, but it is not immune to the effects of temperature changes, moisture variations, and other environmental factors. Over time, brickwork and blockwork expand and contract, which can lead to cracking, bulging, or other structural problems. Movement ties, sometimes known as slip ties or expansion ties, provide a specialised solution to this challenge. By accommodating the natural shifts in a wall, these ties help prevent permanent damage and maintain a building’s stability and longevity.
This article explains how and why masonry walls move, the role movement ties play in protecting these walls, and practical advice for selection and installation. If you have not already explored our main hub piece, “The Ultimate Guide to Wall Ties: Types, Applications, and Installation Best Practices,” you may wish to read that first for an overarching look at cavity wall ties, including general installation guidance and compliance with UK standards. Once you have a broad sense of wall tie principles, you can explore in detail how movement ties address expansion and contraction in brickwork.
1. Understanding Expansion and Contraction in Masonry
Masonry walls experience movement due to several factors, notably temperature fluctuations and variations in moisture content. In summer, bricks and blocks can heat up and expand; in cooler or drier conditions, they contract or shrink. Mortar itself also exhibits some degree of movement, especially in the initial curing stages when it loses moisture. While these changes may be minor, they can add up over time if the wall is not designed to accommodate them.
Thermal expansion becomes more pronounced in exposed areas of a building, such as sunlit façades or walls that face strong winds. In addition, modern building designs often feature larger uninterrupted lengths of brickwork. The longer the wall, the more expansion and contraction it can exhibit, increasing the potential for cracks if it is not given room to “breathe”.
Movement is not inherently problematic. It only becomes an issue when stresses build up without a path to dissipate. In masonry walls, cracks often form at weak points like door and window openings, or at junctions with other parts of the building. In extreme cases, repeated thermal cycles may lead to substantial cracks or cause sections of brickwork to bulge outward.
2. The Role of Movement Ties
Movement ties are specially designed connectors that link portions of a masonry wall while allowing enough flexibility or slip to accommodate changes in length or height. Unlike standard cavity wall ties, which are relatively rigid and aim to keep two leaves of masonry (or masonry and a timber frame) moving in unison, movement ties often feature slotted or flexible sections that permit controlled movement in one or more directions.
Their main function is to control where and how movement occurs. By localising expansion and contraction, movement ties reduce the stress in mortar joints and other potentially vulnerable areas. This helps maintain the integrity of the overall structure, preventing random cracking or unexpected shifts that can be both unsightly and costly to repair.
Movement ties are particularly valuable in taller buildings or long walls, where the cumulative effect of expansion can be substantial. They also matter in new builds with modern, lightweight materials that expand or contract more noticeably. In short, movement ties provide a systematic way to handle one of the most common yet often overlooked processes in masonry construction.
3. Typical Applications for Movement Ties
Movement ties see the most use in situations where expansion and contraction are heightened by design or environment. Examples include:
Tall or Long Masonry Walls
Large façades or runs of brickwork that do not incorporate frequent movement joints often need movement ties to distribute expansion stresses.
Multi-Storey Buildings
High-rise or multi-residential buildings are subject to more movement because of temperature differentials across floors and external pressure changes.
Buildings in Extreme Climates or Coastal Areas
Strong sunlight, intense wind, or salt spray can accelerate weathering and thermal cycles, making robust movement solutions essential.
Facade Upgrades or Extensions
Renovations or extensions that join to existing walls may call for movement ties to ensure the old and new parts of the structure integrate smoothly.
Wherever you have a scenario that requires a little “give” in the masonry to prevent cracks, movement ties can be valuable. You may choose to incorporate them in combination with standard wall ties, so that some sections of wall remain rigidly bonded while others have the capacity to move.
4. Installation Guidance and Best Practices
Installing movement ties typically involves positioning them along movement joints—vertical or horizontal joints deliberately placed in the masonry to accommodate expansion. The tie is anchored on one side, often with a flexible slot on the other side, allowing movement along the plane of the joint. Key considerations include:
Correct Spacing
It is essential to follow the manufacturer’s recommendations, as well as building regulations, for tie spacing both horizontally and vertically. Movement ties are often installed at regular intervals along the expansion joint.
Embedment Depth
Each end of the tie must have sufficient anchorage, whether in a mortar joint or a supporting frame. Manufacturer guidelines will specify the required embedment depth, which might vary for different cavity widths or tie designs.
Orientation
Movement ties must be installed so that the slot or flexible section aligns with the direction of anticipated movement. If the tie is oriented incorrectly, it may impede rather than facilitate movement.
Mortar Quality
Poorly mixed or cured mortar can compromise the performance of any tie, including those designed to allow movement. Ensuring consistent mortar joints and careful trowelling around the tie is crucial to preserving the slot’s functionality.
Clean Cavity
As with standard wall ties, mortar droppings in the cavity could block the movement slot or create bridging problems. During installation, keep the cavity as clean as possible to enable the tie’s flexible section to work freely.
6. Common Mistakes to Avoid
Movement ties provide a critical function, but they can be rendered ineffective if installed improperly. Some of the most common mistakes include:
Misaligned Ties
If the slot does not match the direction in which the wall needs to move, the tie cannot serve its purpose. Careful planning and clear communication on-site help avoid this error.
Excessive Bending or Modification
Movement ties are engineered to slip or flex within specific tolerances. Over-bending them or cutting them to size in an ad-hoc manner can undermine those design characteristics.
Inadequate or Non-Existent Movement Joints
Installing movement ties without an actual movement joint can prove pointless. The joint is what allows the masonry to shift, so the presence and correct formation of that joint is fundamental.
Over-Reliance on a Single Movement Tie Type
Different parts of a building may require varied strategies for handling expansion. In large-scale projects, consult a structural engineer or follow detailed design guidelines that might specify multiple tie types or additional expansion solutions.
Ignoring Other Forms of Movement
Thermal expansion is not the only reason masonry shifts. Differential settlement, changes in moisture content, and load variations can also contribute. Movement ties usually address horizontal or vertical brickwork expansion, but other structural concerns may call for different solutions.
7. Integrating Movement Ties with Other Wall Ties and Building Elements
Movement ties often work alongside standard cavity wall ties, damp proof courses, fire barriers, and other protective measures. Ensuring these elements complement one another can enhance the durability and efficiency of the overall building envelope.
For instance, if you are already using low thermal conductivity ties to minimise heat bridging, you could look for movement tie options that maintain similar thermal characteristics. Alternatively, if your building design involves a timber frame, you must confirm that the movement ties can attach properly to the wooden structure without compromising the slip feature.
Moisture management is another consideration. Movement ties must not inadvertently form a path for water to cross the cavity. Many designs include a drip feature or special shape to manage moisture. Coupling these with a well-installed damp proof course and functional weep holes helps guard against damp patches and mould. If you want more guidance on these protective measures, you can turn to our “Complete Guide to Damp Proof Courses (DPC)” or our “Weep Holes” hub to see how they integrate with wall tie systems.
8. UK Regulations and Standards for Movement Ties
While no single document exclusively focuses on movement ties, British Standards such as BS EN 845-1 cover the performance and testing of wall ties and ancillary masonry components. Approved Document A (Structure) of the Building Regulations highlights the need to handle structural movements appropriately, and guidance from the National House-Building Council (NHBC) often outlines best practices for expansion joints and tie density in residential builds.
Although each project may have bespoke requirements, you can expect building control officers or inspectors to assess whether movement joints, ties, and other details align with recommended good practice. Working with manufacturers that provide CE or UKCA marked products usually streamlines compliance, as these labels signify adherence to relevant testing standards.
9. Sourcing Movement Ties and Expert Advice
At Spechunter, we supply an array of movement tie solutions suitable for different cavity widths, design loads, and budget considerations. You can browse our wall ties page to find not only standard ties but also specialised ones from well-known manufacturers, each tested and approved for use in the UK.
If you are unsure which tie design best suits your project, our technical support team can help. We can advise on tie spacing, the need for multiple solutions in a single structure, and integration with other building elements like insulation and fire barriers. With our next working day delivery on many products, it is easy to keep your site running smoothly, even when last-minute changes arise.
The Low-Down
Movement ties represent a smart and often essential way to cope with the ongoing expansion and contraction of masonry. Rather than allowing cracks to form and compromise the building envelope, these ties introduce just enough flexibility to manage stress without sacrificing stability. They are especially valuable in modern construction, where longer unbroken runs of brickwork and increasingly strict performance demands can magnify the effects of thermal and moisture-driven movement.
Whether you are working on a new-build home, a tall commercial building, or a renovation that abuts existing masonry, understanding how movement ties work—and installing them correctly—can save time and money in the long run. If you need support selecting or sourcing high-quality movement ties, Spechunter is here to help. By offering leading brands and expert advice, we can supply the right ties for your project’s requirements and facilitate swift delivery so you can stay on schedule.