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Cavity Wall Ties – Uses, Selection and Identifying Failure

What is a wall tie?

Wall ties, which are commonly referred to as brick ties, are utilized in structures that have cavity walls to link the external and internal leaf walls, allowing the two leaf to function in sync with one another. While they’re hidden from view after building wall ties play a crucial role in building stability.

The most serious structural problems can result due to the insufficient or improper use of wall ties , such as masonry cracks, dampness and, in extreme cases, perhaps the loss of outer leaf wall. In My Trade Products we stock the trusted and tested Ancon brand, which is one of the world’s experts in fixing, connecting lifting and anchoring technologies for the construction industry since 1882.

These days, wall ties are typically made of stainless steel because it is able to resist corrosion caused by moisture and cement without the need for extra layer of protection. Ancon wall ties Ancon wall ties have an unmaintained life span and are specifically designed to limit the amount of material used to the minimum. Certain composite materials are employed, like Ancon’s Teplo range of ties that consist of pultruded basalt fibers that are set in resin matrix. These ties is ideal for ultra-low energy construction, where the reduction of thermal bridging is crucial.

Installation of Wall Ties

In typical brick-to-block construction, the wall ties are constructed into the inner and outside leaves. The wall ties must be put into the block the mortar, then covered with fresh mortar. Be aware that wall ties shouldn’t be placed in a pre-built joint. When installingthem, an even slope should be used to allow water to flow through the cavity and towards the leaf’s outer edge. The drip portion of the tie must point downwards and be placed near the center of the cavity.

If you are building a different kind of cavity wall, such as blocks made of thin-joints or timber/steel frames then wall ties should typically be put in place following the time that the inner leaf is built and also during the construction of the outer masonry leaf.

What spacing and position do you need to use for wall tie?

If the leaves in the wall cavity are thicker than 90mm then it is recommended to install 2.5 walls ties for each square meter with a maximum horizontal space of 900mm and a maximum vertical spacing of 350mm. Always verify your local Building Regulations however as this could be different in certain circumstances. Spread the wall ties evenly across the wall in a staggered arrangement, excluding around openings such as doors, windows roof verges, unreturned/unbonded edges, and vertical movement joints. The vertical spacing of the wall ties must be decreased to a maximum of 300mm, and not more than 200mm from the edge of the opening. This could result in the wall tie being placed on each blockwork course within 225mm of the openings. The spacing can be loose if the joint is an unboned tie that spans the joint.

What kind of wall tie do you recommend?

Masonry to Masonry

There are a variety of factors to consider when choosing the best wall tie for the job like the type of masonry, the cavity width the number of courses/heights of construction and the location of the building.

The various aspects that affect the proper usage of wall tie in any context are covered in a variety of Eurocodes as well as Building Regulations, which should be considered and followed. In addition to these Building Regulations and Eurocodes, Ancon in the UK Ancon has an additional published document (PD 6697:2010) that aids when selecting wall ties according to topographic and geographic factors. This means that, most of the time the cavity wall ties can be identified without the involvement of structural engineers.

Frame ties for Masonry and Timber

Timber frame ties are made to accommodate vertical movement that is caused by the expansion and shrinking of materials that have different characteristics of thermal expansion. The wall tie must be able to deal with the different movement and therefore it is essential to choose the right tie for the type of movements expected by the building. Ancon’s ties STF6 and Tim6 permit 24mm frame shrinkage, and can be used for all timber-framed structures up to 4 stories high. Ancon TFMT7 Ancon TFMT7 is specifically designed to permit greater movement up to 65mm, and is thus is suitable for bigger buildings.

Recognizing Wall Tie Failure

It is difficult to determine the exact moment the wall tie is failing and what the cause of the failure , but the most frequent indication is the regular horizontal cracks that appear in the wall’s outer. When the wall tie begins to rust, it expands, causing the mortar to crack , let water in. Sometimes, this rust builds and cause expansion, which could cause the wall to be distorted. wall, causing it to bow or bulge.

Another thing to watch out for is cracks in the windows masonry. As the rust accumulates on the wall, the force creates cracks in the window reveals , which are particularly vulnerable to structural damage.

If the lintels on windows and doors appear like they’ve been lifted or sagging, it could be a indication.

If you suspect that there is an issue with your wall tie Professional assistance from a surveyor is recommended. They are equipped with specialist equipment and detectors that can determine the degree of destruction of your wall tie.