Wall ties, sometimes called ‘brick ties’, are used in buildings with cavity walls. They are used to join the two leaves of a cavity wall together, allowing the two parts to act as a homogeneous unit. Hidden from view after construction, the wall tie plays a vital role in ensuring the stability of a building.
Inadequate or improperly installed wall ties can lead to serious structural problems, including moisture penetration, masonry cracks, and even the collapse of exterior brick leaves. Wall ties are made of corrosion and fire-resistant materials and include a drip structure to prevent water from passing through the inner leaf.
The Butterfly Wall Tie made from mill galvanized & hot-dipped galvanized steel wire, stainless steel wire. It is used for connecting brick cavity walls. It is suggested to use 3-4 Butterfly Wall ties per m2. To calculate the length of the Butterfly Wall Tie required to deduct 20-50 mm from the entire wall thickness including the cavity.
Butterfly Wall Tie
Most buildings constructed since the 1920s have hollow walls. Over the years, the shape of wall ties has changed dramatically and a variety of now obsolete materials have been used, such as plastic, galvanized steel. prior to 1978, wall ties were typically made of galvanized mild steel. These ties were expected to last the entire life of the building, but it was later recognized that these wall ties would corrode after only 15-20 years.
Today, wall ties are primarily made of stainless steel, which is now readily available on the market and can withstand corrosion from water and cement without additional protection. Modern stainless steel wall ties offer a maintenance-free life and are value engineered to reduce material content.
Wall Strip Installation
Wall Tape Insertion
Wall Tie Insertion
In standard brick-to-block construction, walls are embedded in foliage during construction. To ensure that the wall straps effectively tie the leaves together, they should be pressed in and then surrounded by fresh mortar, never pushed into the precast joints. When installed, they should fall slightly onto the outer leaves, not toward the inner leaves, as this provides a path for moisture to travel through the cavity. The drip portion of the tie should face down and be located near the center of the open cavity.
In other types of cavity wall construction, such as thin joint block and timber or steel framing, wall ties are typically installed after construction of the inner leaf and during construction of the outer leaf of the masonry.
Ties must be long enough to span the cavity and provide a minimum mortar embedment at both ends, typically 62-75 mm. For example, a 200 mm long wall band is suitable for a 50-75 mm cavity. As energy efficiency standards have increased, cavities have become wider to accommodate thicker insulation depths. Standard wall ties are now available for cavity widths of 50 mm to 450 mm.
The minimum density of cavity wall ties (as defined in Eurocode 6) is 2.5 ties per square meter. Typically, they are installed at 900 mm horizontal x 450 mm vertical spacing and should be staggered in the wall area to provide uniform distribution. Additional ties should be used every 300 mm height around openings and unglued edges (although block alignment usually means they are installed at 225 mm vertical spacing).