Cavity wall ties are fasteners that join the internal and external walls of a cavity. They span the cavity and lock into the mortar at the ends. If you’re replacing ties, you need to know what to look for. There are several common problems with ties. Learn about the different types and how they can be repaired.
Types of ties
When installing cavity wall ties, it is important to select the right one for the job. There are several types available and the right one depends on the building’s design, height and intended use. Some ties are suitable for high-rise buildings, while others are suitable for lower-rise buildings. For example, a type 1 tie is designed for buildings of up to 15 metres high.
Some types of ties are self-tapping, hammered into the walls. Self-tapping ties are strong enough to hold the load, but still allow for a degree of differential movement. These ties are recommended for buildings with a modern design, as they prevent rainwater from running across the inner masonry. Moreover, most ties feature a drip feature to prevent leaking. This feature can be in the form of a deformation in the tie or retrofitted drip ring.
Some cavity wall ties are corroded and can lead to cracking of the mortar joints. This is why a proper inspection of these ties is important. A qualified professional should be able to identify the types of wall ties present in a building. In addition, the inspector should understand the different types of structural movement that promotes corrosion.
When installing cavity wall ties, it is vital to carefully consider the type of material that is used for them. Some of the most common types of wall ties are made of steel and iron. Steel and iron ties are prone to corrosion, especially in damp conditions. Galvanized steel ties, on the other hand, are designed to resist corrosion.
Some cavity wall ties are made of 304-grade stainless steel rods that can expand and contract by about fivemm. They are usually installed by drilling a hole in the wall about 10mm deep. These ties are fitted with a special nut on the drill. They are a good choice when the brickwork is in good condition.
Type 4 wall ties are the lightest duty type. These ties are used to join two masonry leaves together in small projects. They are suitable for domestic and small-scale commercial projects. They also have a low wind resistance and can be used to join masonry leaves.
Cost of tying replacement
The cost of replacing cavity wall ties can vary greatly, depending on the size of the wall space and the type of wall tie that needs to be replaced. The cost of these repairs will typically include the costs of surveying the property and consulting an expert. The professional should also be qualified to handle the work.
A professional surveyor will use specialized equipment to examine the wall tie and check for signs of failure. They can also estimate the cost of replacing the wall ties. This can be done at a low cost, or even for free. You can find many companies offering free surveys, but make sure the surveyor is independent. It’s better to use a surveyor that isn’t associated with a wall tie supplier as this can create a conflict of interest.
To assess whether wall ties need replacing, first measure the width of the cavity. The gap between the internal and external walls is usually about ten to eleven inches. Then subtract the thickness of the outer wall from this measurement. This will give you a ballpark figure for the cost of replacing cavity wall ties.
Wall ties are an essential component of cavity wall construction. They provide structural support and connect the internal load-bearing leaf to the protective outer leaf. These ties are generally made of stainless steel, which is known for its corrosion-resistant properties. However, older buildings may have ties made of other materials. In those cases, they were made of galvanised mild steel. Galvanised wall ties were initially expected to last the life of the building, but deterioration and rusting can reduce the ties’ strength over time.
It is possible to identify if wall ties need to be replaced without professional help, but the cost varies greatly depending on the size of the building and the number of ties in the wall. Signs of failure can include cracks in the brickwork or bulging windows. Additionally, window reveals can separate, lintels can sag and the outer leaf may pull away from the inner leaf.
During construction, faulty wall tie installation can cause gaps or short ties. Often, this faulty installation may lead to structural failure. A wall tie replacement system can help you prevent such a problem by anchoring the brick facade securely and transferring the load.
Common problems with tying
Cavity wall ties are an essential part of a home’s structure. But if they are installed incorrectly, they can fail. Common problems with cavity wall ties include improper spacing, bad workmanship, or faulty mortar. Here are some ways to ensure that your ties don’t fail:
Cavity wall ties are double-triangular structures used to reinforce exterior walls. If they are not installed properly, water can leak in and cause corrosion. The corrosion won’t break the steel, but it will cause it to expand and cause cracks. As a result, the outside leaf of a house can collapse. This is particularly dangerous if the wall ties are galvanized.
To avoid these problems, consider contacting a cavity wall tie company for advice. These companies have systems in place to ensure accurate diagnosis and effective treatment options. A typical treatment includes removing corroded wall ties and swapping them with new ones. However, it is best to avoid placing ties too close to hidden services.
Another common problem is poor embedding in the mortar joint. If the wall ties are too short, they won’t embed enough into the wall and could cause premature bulging or collapse. Likewise, if they are too long, they can over-load the walls and reduce their lateral capacity.
When wall ties fail, masonry window reveals may show cracks or rust. Sagging lintels are another warning sign of a failing wall tie. A qualified structural engineer can inspect the property and use specialist equipment to detect problems. In addition to looking for cracks, a professional surveyor can detect a weakened tie using the boroscope.
Another common problem with cavity wall ties is poor insulation. Many wall tie installers don’t bother to install cavity wall insulation, despite its obvious benefits. Typically, the insulation in cavity walls is an old foam or bead-type material that will not prevent the loss of heat and allow water vapour to pass freely.
Cavity wall ties are not suitable for all types of brickwork. It’s also not possible to use them in properties with lightweight blocks. The thickness of the brickwork is also important. If the wall is narrow, it may be difficult to install a wall tie.