Cavity wall tie survey2026-05-14T13:26:01+00:00

Cavity Wall Tie Survey

At Northwest Wall Ties, we pride ourselves on delivering some of the most detailed wall tie surveys and reports available. Using specialist equipment, including borescope inspections, we accurately assess the condition of existing wall ties and identify any signs of corrosion, failure, or structural risk.

We are also known for our fast turnaround times. In most cases, your full written report is completed the same day or next day, helping you avoid delays—especially when dealing with property sales, mortgage requirements, or structural concerns.

Our reports are clear, honest, and tailored to your property, giving you a full understanding of the condition of your wall ties along with straightforward recommendations where required.

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Cavity Wall Tie Survey

At Northwest Wall Ties, we provide detailed wall tie surveys using specialist equipment, including borescope inspections, to accurately identify corrosion, failure, and structural risks. Our clear, honest reports are typically completed the same or next day, helping avoid delays with property sales, mortgage applications, and structural concerns.

All recommendations are based on industry-recognised BRE guidance, including BRE Digest 329 and 401. Wall ties are assessed against official BRE corrosion classification charts, which are included within every report for full transparency. This ensures our recommendations are based on independently recognised standards and proven assessment criteria—not personal opinion—giving you confidence in any remedial advice provided.

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What Are Cavity Wall Ties?

Cavity wall ties, such as fishtail ties made of iron or steel, play a crucial role in construction by connecting the inner and outer walls of a cavity wall. Beginning in the early 1920s, the innovation of the Butterfly tie, crafted from twisted wire, emerged as an alternative.

Positioned horizontally within the wall cavity and secured with mortar, these ties fortify the structure by preventing moisture from traversing from the exterior to the interior wall. Their strategic design is integral to ensuring the safety and stability of the wall. In the absence of proper wall ties, or if they become corroded over time, substantial sections of brickwork—such as gables—can succumb to the forces of wind suction, leading to potential collapse.

What Causes Wall Ties To Corrode?

Cavity wall ties, traditionally manufactured from iron or steel, are vulnerable to corrosion in damp and exposed conditions. To reduce this risk, early ties were protected using zinc and bitumen coated galvanisation. However, over time these coatings can deteriorate, leaving the metal susceptible to rust and eventual failure.

The first British Standard wall ties with a specified zinc coating were introduced in 1945, with further improvements made in 1981. Despite this, wall ties installed prior to 1981 are commonly found to fail prematurely due to factors such as aggressive mortars, prolonged exposure to moisture, and inconsistent or inadequate galvanisation.

Different types of wall ties can fail in different ways. Fishtail wall ties tend to expand as they corrode, leading to horizontal cracking in the outer masonry. In contrast, wire butterfly ties may corrode and fail without noticeable expansion, often resulting in bulging or instability of the wall.

To ensure long-term structural integrity, it is strongly recommended that older wall ties are replaced with modern stainless steel systems, which provide significantly improved durability and resistance to corrosion.

Common Signs of Wall Tie Failure

If left untreated, failing wall ties can lead to serious structural issues. Below are the most common signs to look out for.

A professional wall tie survey is essential to identify the original tie type used in construction. Certain types must be isolated or removed after installing a new wall tie system.

Even with new ties installed, old redundant ties can continue to corrode and expand, causing further cracking and damage if not addressed correctly.

  • Horizontal Cracking

    Horizontal cracks usually appear in the mortar joints and are commonly caused by the expansion of corroding wall ties. As the steel rusts, it expands and forces the surrounding masonry apart.

  • Bulging Masonry

    Bulging or bowing walls occur when wall ties fail and no longer restrain the outer leaf. In severe cases, this can lead to instability and potential collapse if left untreated.

  • Window / Door Opening Distortion

    Gaps or distortion around windows and doors can occur when the wall loses stability. Failed ties allow movement, which puts pressure on openings and causes misalignment.

  • Roof Edges Lifting

    In some cases, expansion and cracking can affect how loads are distributed. This can result in lifting at roof edges or gable movement due to the outer leaf no longer being properly restrained.

  • Stepped Cracking

    Stepped cracking follows the mortar joints in a stair-step pattern. This is a strong indication of wall tie failure, where expansion or movement is transferring stress through the brickwork.

Signs of Wall Tie failure

  • Horizontal Cracking

    Horizontal cracks usually appear in the mortar joints and are commonly caused by the expansion of corroding wall ties. As the steel rusts, it expands and forces the surrounding masonry apart.

  • Bulging Masonry

    Bulging or bowing walls occur when wall ties fail and no longer restrain the outer leaf. In severe cases, this can lead to instability and potential collapse if left untreated.

  • Window / Door Opening Distortion

    Gaps or distortion around windows and doors can occur when the wall loses stability. Failed ties allow movement, which puts pressure on openings and causes misalignment.

  • Roof Edges Lifting

    In some cases, expansion and cracking can affect how loads are distributed. This can result in lifting at roof edges or gable movement due to the outer leaf no longer being properly restrained.

  • Stepped Cracking

    Stepped cracking follows the mortar joints in a stair-step pattern. This is a strong indication of wall tie failure, where expansion or movement is transferring stress through the brickwork.

  • Outer Leaf Movement / Separation

    When wall ties fail completely, the outer leaf can begin to separate from the structure. This is a serious issue and requires urgent attention to prevent further structural damage.

  • Brick Spalling

    Bricks may begin to crack or break apart due to pressure from expanding corroded ties. This is often seen alongside horizontal cracking and indicates ongoing internal stress

  • Cracks in Render

    Cracks in rendered surfaces can indicate underlying structural movement. In many cases, this is caused by failing wall ties expanding and pushing against the outer leaf.

  • Vertical Cracking

    Vertical cracks can form when sections of the wall begin to move independently. This is often linked to failed or missing wall ties allowing separation between the inner and outer leaf.

  • Important

    A professional wall tie survey is essential to identify the original tie type used in construction. Certain types must be isolated or removed after installing a new wall tie system.

    Even with new ties installed, old redundant ties can continue to corrode and expand, causing further cracking and damage if not addressed correctly.

Cavity Wall Tie Survey

If you suspect issues with cavity wall tie failure, or require confirmation for a property transaction, it’s essential to instruct a specialist surveyor. We provide comprehensive cavity wall tie surveys designed specifically to support homeowners, buyers, sellers, and mortgage lenders.

Our reports are fully mortgage-ready, making them suitable for submission to lenders and solicitors. They are among the most detailed on the market, combining technical accuracy with clear, structured findings—delivered with a fast turnaround to keep your transaction moving.

Our expert surveyors carry out thorough inspections in accordance with recognised industry standards. Using advanced diagnostic equipment, including endoscopes and metal detection tools, we assess the condition of wall ties, identify defects within the cavity, and highlight any associated cracking or movement in the masonry.

To ensure complete objectivity, we grade all wall ties in line with BRE Digest guidance and established chart criteria. This removes subjectivity from the process—our recommendations are based on proven industry data rather than opinion, giving lenders and clients confidence in the findings.

Following the survey, you will receive a clear, professional report outlining the condition of the wall ties, supported by photographic evidence, grading, and, where necessary, recommendations for remedial work along with a detailed quotation.

Wall Tie Inspection

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Our instant quote tool makes it quick and easy to get a price for your cavity wall inspection report. Simply enter a few basic details, including the property address requiring inspection, and you’ll receive an accurate quote instantly. You can then book your survey online in just a few clicks.

We won’t ask for or store your personal contact details unless you choose to proceed with the booking.

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Why choose Northwest Wall Ties

 

  • Family Values: As a family-run business, we understand the importance of trust and reliability. You can count on us to treat your property with the same care and attention to detail as we would our own.

  • Wall Tie Installers Federation Members: Northwest Wall Ties are members of the Wall Tie Installers Federation, registered installers subscribe to a code of practice based on BRE Digests 329 and 401 and the Federation’s own rules. This membership together with adherence to BRE standards provides reassurance to our customers on the quality of our work.

  • Expertise: With years of experience in cavity wall tie inspection and repair, we have the knowledge and skills to deliver superior results, no matter the complexity of the project.

  • Customer Satisfaction: Your satisfaction is our top priority. We go above and beyond to exceed your expectations and ensure a smooth and hassle-free experience from start to finish.

  • Quality Assurance: We stand behind the quality of our workmanship and materials, ensuring that your property receives the best possible care and attention.

When it comes to protecting your property, trust the experts at Northwest Wall Ties to deliver reliable solutions you can depend on. Contact us today to learn more about our services and how we can help safeguard your investment for years to come.

Remedial Wall Tie Specialists

Cavity Wall Tie Survey FAQs

Common questions about cavity wall tie surveys, costs and what to expect.

What is a cavity wall tie survey?2025-02-11T14:17:14+00:00

A cavity wall tie survey is an inspection process that evaluates the condition of the metal ties connecting the inner and outer leaves of a cavity wall. The survey aims to identify any signs of corrosion, failure, or inadequacy in the wall ties, which are crucial for maintaining the structural integrity of the wall. The procedure typically involves:

  • An external appraisal of the building to identify construction details, the presence of a cavity, insulation, and any visible cracks or defects.

  • Using a metal detector to locate wall ties.

  • Drilling small inspection holes near the ties and employing a borescope to visually assess their condition.

  • Photographing the ties for further analysis and record-keeping.

This process is straightforward and usually takes less than an hour.

Why are cavity wall ties important?2025-02-11T14:18:42+00:00

Cavity wall ties play a crucial role in construction by connecting the inner and outer walls of a cavity wall. Positioned horizontally within the wall cavity and secured with mortar, these ties fortify the structure by preventing moisture from traversing from the exterior to the interior wall. Their strategic design is integral to ensuring the safety and stability of the wall. In the absence of proper wall ties, or if they become corroded over time, substantial sections of brickwork—such as gables—can succumb to the forces of wind suction, leading to potential collapse.

What causes cavity wall ties to corrode?2025-02-11T14:19:38+00:00

Cavity wall ties, initially made from iron or steel, are prone to corrosion in damp conditions. To prevent this, they were galvanized with zinc. However, this protective layer can degrade over time, leading to failure. Pre-1981 wall ties often fail prematurely due to various factors such as corrosive mortars, exposure to rain, and substandard galvanizing. Fishtail wall ties expand upon corrosion, causing cracks in the outer leaf, while Wire Butterfly ties may snap without expansion, resulting in wall bulges. Replacement of older wall ties with modern stainless steel ones is recommended to prevent future failures.

What are the signs of cavity wall tie failure?2025-02-11T14:20:05+00:00

Signs of cavity wall tie failure include:

  • Horizontal Cracks: Found in the mortar, often at a high level, caused by the expansion of corroded wall ties on the external leaf.

  • Bulging Brickwork: Indicates snapped wall ties, which can make your property unstable.

  • Internal Cracking: Caused by the expansion of corroded wall ties.

  • Cracks in the Render: Vertical cracks in the render.

  • Roof Edges Lifting: The inner leaf carries the roof load, but as corroded wall ties expand and crack the mortar, the outer leaf takes the load, resulting in forcing the roof upwards or the gable ridge to rise.

If you observe any of these signs, it’s essential to consult a specialist for a comprehensive survey.

How is a cavity wall tie survey conducted?2025-02-11T14:21:58+00:00

A cavity wall tie survey involves several steps:

  • External Assessment: The surveyor examines the building’s exterior to identify construction details, the presence of a cavity, insulation, and any visible cracks or defects.

  • Locating Wall Ties: A metal detector is used to find the positions of the wall ties.

  • Inspection: Small inspection holes are drilled near the located ties, and a borescope (a type of endoscope) is used to visually assess their condition.

  • Documentation: Photographs of the wall ties are taken for further analysis and record-keeping.

This procedure is straightforward and usually takes less than an hour.

What happens if wall ties are found to be corroded?2025-02-11T14:22:27+00:00

If a survey reveals that wall ties are corroded or failing, replacement is typically recommended to maintain the structural integrity of the building. The process involves:

  1. Locating Existing Ties: Identifying the positions of the old wall ties.

  2. Installing New Ties: New stainless steel mechanical or resin-bonded ties are installed in an offset pattern to the existing ones.

  3. Isolating Old Ties: The old ties are isolated by removing the surrounding mortar or by using grease-filled sleeves over the exposed ends to prevent further corrosion and expansion.

The work is carried out from scaffolding or temporary scaffold towers, depending on terrain and access. Stainless steel wall ties are used as they are corrosion-resistant. Replacement cavity wall ties also benefit from long-term guarantees.

How often should cavity wall ties be inspected?2025-02-11T14:28:51+00:00

The frequency of inspections depends on the age and condition of the property. For properties built before 1981, especially those in exposed or coastal areas, regular inspections are advisable due to the higher risk of wall tie corrosion. If you notice any signs of wall tie failure, such as horizontal cracking or bulging brickwork, it’s essential to arrange a survey promptly.

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