Remedial Wall Ties: Diagnosing and Correcting Tie Failures in Existing Buildings
Wall ties are an essential—but often hidden—component that holds the external and internal leaves of a cavity wall together, ensuring structural stability and preventing issues like bulging or cracking. However, in many older properties, ties may have deteriorated over time or been poorly installed in the first place. This leads to a phenomenon known as wall tie failure, where the ties no longer effectively perform their function. When this happens, the building’s structural integrity can be compromised, and remedial action becomes imperative to avoid long-term damage.
In this article, we explore the causes of wall tie failure, the warning signs that suggest a building may require remedial ties, and the methods available for diagnosing and correcting problems. If you are new to the concept of wall ties and their role in masonry, you may wish to review our hub piece, “The Ultimate Guide to Wall Ties: Types, Applications, and Installation Best Practices,” for a foundational understanding of what wall ties are and why they matter. Once you have that context, learning about the specialist area of remedial ties will show you how even ageing or compromised walls can be restored to safety and stability.
Understanding the Causes of Wall Tie Failure
While modern buildings typically use stainless steel wall ties designed to last the structure’s lifespan, older properties often relied on galvanised steel or zinc-coated ties. Over the decades, these protective coatings can degrade, leading to corrosion. Where corrosion sets in, the ties expand, crack mortar joints, or lose the integrity to hold the cavity leaves together.
Beyond corrosion, other factors that contribute to tie failure include:
Inadequate Tie Density or Embedment
Some historical builds did not adhere to strict spacing guidelines, leaving large sections of wall inadequately tied. Similarly, ties might have been installed with too little embedment in mortar, leading to a weak bond.
Poor Original Installation
Even if older ties were made from robust materials, they can fail prematurely if they were placed incorrectly—perhaps with the drip point buried in mortar or the orientation reversed.
Structural Movement
Subsidence, settlement, or repeated thermal expansion and contraction can stress older ties beyond their limits. Over time, repeated cyclical loading can cause micro-fractures and eventual failure.
Moisture Ingress
If the cavity is bridged by debris or the damp proof course (DPC) is compromised, heightened moisture levels can accelerate corrosion, especially if the original galvanised coating is damaged.
As UK building stock ages, these issues become increasingly common in homes dating from the mid-20th century or earlier. Many property owners only discover the scale of the problem when cracks appear, or the external leaf begins to bow outwards. Understanding these warning signs is the first step toward diagnosing and remediating wall tie issues.
Identifying Signs of Tie Failure
The symptoms of wall tie failure can be subtle at first, but they tend to become more visible as the problem escalates. Some typical indicators include:
Horizontal Cracks in the Mortar Joints
As corroded ties expand, they often push against the mortar bed, leaving a characteristic horizontal crack at bed joint level.
Bulging or Bowing of the External Leaf
If the ties are no longer holding the masonry leaves together, the outer leaf can bow away from the structure under wind load or its own weight.
Rust Stains or Lumps on the Brick Face
Sometimes the corrosion can manifest as brownish stains that seep through mortar joints. In advanced stages, lumps or spalls may appear on the brick face near the embedded tie.
Debonded Mortar and Loose Bricks
In severe cases, entire sections of mortar may become loose, or bricks can shift out of alignment, indicating inadequate lateral support.
A professional survey, often involving borescope cameras, metal detectors, and visual inspections, is usually the next step once warning signs appear. Surveyors can locate the existing ties, assess their condition, and determine how many are still providing structural support.
Survey and Diagnosis Methods
Accurately diagnosing wall tie failure is crucial to selecting the best remedial approach. Common diagnostic techniques include:
Metal Detection and Probing
A handheld metal detector can help locate ties in the wall. Once found, the surveyor can gently remove small sections of mortar for closer examination or use a borescope inserted through a drilled hole.
Borescope Inspection
This method involves sending a small camera through the mortar joint. The footage helps assess the presence of rust, the tie’s orientation, and the cavity’s condition (including any bridging debris).
Tie Density Assessment
The surveyor verifies that enough ties were originally installed per square metre—2.5 ties/m² is a common guideline, although older builds may not meet this standard.
Mortar Analysis
In some cases, the mortar itself might have weakened, exacerbating tie failure. Lab tests can reveal issues like high chloride content or insufficient bonding agents.
These methods allow specialists to classify the ties as either corroded, fractured, underperforming, or missing. From there, a remedial plan can be formed, balancing the need to stabilise the building with considerations such as budget, aesthetics, and occupant safety.
Overview of Remedial Tie Solutions
Once you have identified tie failure, a remedial strategy is critical to restore the building’s stability. Modern remedial wall ties generally fall into several categories:
Mechanical Expansion Ties
Often inserted into pre-drilled holes in the masonry, these ties expand when tightened, gripping both the outer and inner leaves of the wall. They are typically stainless steel and may incorporate features like plastic sleeves or special heads to ensure a secure fit.
Resin or Chemical Fix Ties
After drilling holes into each leaf of the cavity wall, a two-part resin is injected before placing the tie. This resin cures around the tie, effectively bonding the steel to the masonry. The advantage is a strong and corrosion-resistant bond.
Helical Ties
Resembling a twisted or spiral-shaped rod, these ties are driven or hammered into the mortar bed. The helical shape ensures a firm anchorage by interlocking with the brick or block. Some helical ties also incorporate resin at the ends for extra stability.
Each system has its advantages in terms of ease of installation, cost, and load capacity. Factors like the cavity width, the building’s height, and the condition of the masonry layers often dictate which approach is most suitable. An experienced contractor can advise on the best choice given the wall’s particular problems.
Installation Process and Best Practices
Although the specifics vary by tie type, remedial installations typically follow a similar sequence:
Mark Out Locations
The installer determines where to drill for each tie, aiming to replicate the correct density (e.g., 2.5 ties/m²) or address areas with visible damage. The new tie positions generally need to alternate to achieve a stable bond pattern.
Drill Pilot Holes
Using an appropriate masonry bit, small holes are drilled through the external leaf and partway into or through the inner leaf, depending on the tie design. Care must be taken not to blow out the back of the internal leaf.
Insert Ties
The selected tie system—mechanical, resin, helical, or sock-based—is placed into each hole according to the manufacturer’s instructions. This might include applying resin or expanding the tie to lock it into place.
Check Embedment and Alignment
Installers confirm that each tie extends correctly into both leaves without bridging damp proof layers or insulation. If the tie features a drip or a central indentation, it should remain in the open cavity space.
Seal and Make Good
Holes in the outer leaf are typically filled with matching mortar or a colour-tinted resin so that the repairs blend seamlessly with the existing brickwork. Any interior leaf holes may be patched similarly if they are exposed or accessible.
Post-Installation Inspection
A final check ensures all ties are fully secured and spaced as planned. The presence of a borescope or advanced scanning tool can help verify that ties have taken proper hold in the inner leaf.
Preventing Recurring Issues
Even the best remedial tie strategy can be undermined if the root causes of the original failure are not addressed. Key measures include:
Updating Cavity Insulation or Clearing Bridges
If the cavity is clogged with mortar droppings or old insulation, it should be cleared or replaced before installing new ties to reduce moisture pathways that accelerate corrosion.
Ensuring a Functioning DPC
A compromised damp proof course can allow moisture to travel up through the brickwork, corroding new ties. If your DPC is damaged or missing, consider replacing it. For more insights, consult our “Complete Guide to Damp Proof Courses (DPC).”
Checking for Structural Movement
If subsidence or other structural issues are at play, additional measures—such as underpinning or introducing movement ties—may be required. Our “Movement Ties 101” article discusses how expansion and contraction can affect masonry walls.
Monitoring and Maintenance
Periodic inspections can catch early signs of renewed corrosion or cracking. Although stainless steel remedial ties are highly durable, external factors such as harsh coastal climates can still introduce long-term wear.
Regulatory Compliance for Remedial Works
Remedial tie projects do not always require formal planning permission, but building regulations may apply if the repairs significantly affect the structural integrity of a dwelling. In the UK, any modifications that could influence the building’s stability must align with Approved Document A (Structure). Local building control officers can advise on whether an application or inspection is necessary. If your project is part of an NHBC-backed property, follow NHBC Standards to confirm tie installation and spacing requirements.
Additionally, you should seek ties and resin systems with CE or UKCA markings, showing they meet the relevant product standards under BS EN 845-1 or comparable regulations. This ensures that the new ties themselves are tested for strength and corrosion resistance, mitigating the risk of future problems.
Cost and Timescale Considerations
The expense of remedial tie work can vary widely based on factors like the property’s size, how many ties need replacing, and the ease of access to the walls. However, the cost is usually less than the potential consequences of ignoring tie failure, which could lead to partial collapses, major cracks, or the need for extensive rebuilding of the external leaf.
In many cases, remedial tie installations on a typical domestic property can be completed within a few days to a week, especially if a skilled team is on hand. This timeframe can extend if ancillary repairs—such as repointing, insulation replacement, or DPC installation—are also undertaken.
Sourcing Remedial Ties and Expert Assistance
At Spechunter, we stock an extensive range of remedial tie solutions, including mechanical expansion ties, resin-based fixings, and helical rods from leading manufacturers. We also supply essential ancillaries such as injection resins, grout tubes, and drill bits suited for masonry repairs. Ordering before midday often enables next working day delivery on many items, ensuring minimal disruption to your project’s timeline.
If you need technical guidance, our experienced team is available to discuss specifics around tie type, installation best practices, and how to integrate solutions with updated DPC or cavity insulation. Although we do not conduct on-site surveys, we can advise on the products that commonly address the issues discovered during a professional inspection.
For further reading or to review our range, you can visit our wall ties page, where you will find both standard and remedial tie options. If you are not entirely sure which approach is best, our blog’s comprehensive library of spoke articles and category hubs can help you explore different facets of masonry repairs—from coping with movement to upgrading your building’s thermal performance.
Our final word
Remedial wall tie installation is an increasingly important process as much of the UK’s housing stock ages and previously galvanised or poorly installed ties reach the end of their serviceable life. Recognising the early warning signs of tie failure—like horizontal cracking, bulging masonry, or rust stains—can help you intervene before more serious and costly structural problems arise. Modern remedial tie solutions, from mechanical expansion rods to resin-based anchors, offer reliable ways to restore stability and peace of mind without necessitating a full-scale rebuild of the external leaf.
Whether you are a homeowner looking to protect your investment, a contractor specialising in refurbishments, or a property developer managing a portfolio of older buildings, understanding remedial ties is invaluable. By combining an accurate initial survey with high-quality products, proper installation techniques, and supporting measures like a well-maintained DPC and clear cavity, you can ensure that your building remains safe, structurally sound, and resilient against future deterioration.
If you are unsure about which remedial system suits your wall construction or the severity of corrosion, Spechunter’s technical team is on hand to guide you. We offer fast delivery on a wide array of wall tie products and building sundries, helping you complete repairs with minimal delays. By addressing wall tie failure proactively, you safeguard both the property’s integrity and its long-term value.