Cavity walls provide excellent sound and thermal insulation in addition to reducing the risk of moisture condensation, thereby making them a popular choice amongst many housing projects. Wall Ties are integral to the construction of cavity walls, inasmuch as securing the safety and stability of the cavity walls. The ends of the tie lock tightly into the mortar, spanning the cavity to tie the internal and external walls of bricks or block-work together. The ties keep dampness away from the inner leaf of the wall. Wall ties in their earliest manifestation were either made of cast iron, terracotta, or wrought iron and were replaced by steel made ties shaped as fish tails and butterflies which started to give away due to corrosion. The mantle was taken over by zinc coated stainless steel ties which are at lesser risk of succumbing to corrosion.
New designs in wall ties are producing better results in dealing with temperature changes by expanding within the wall cavity in order to adapt to the external fluctuations in temperature thereby preserving the structure’s durability. Wall ties are being engineered to play the dual role of preventing water seepage from the outer leaf on to the inner wall, and lending greater support and stability to the outer leaf, as the inner wall is thicker in comparison due to its load-bearing role, to help secure the outer leaf’s stability and counter the threat from the outside on multiple counts.
Wall ties made of stainless steel wires manoeuvred to attain qualities fit to deliver insulation clip compatibility along with central cavity drip are mainly used in two-storey residential buildings. Commercial buildings and multi-storeyed structures employ wall ties with a heavier design embedded with central cavity drip, including embedment markings to facilitate proper installation, and enabled with superior adhesion properties.
Wall ties have evolved in their design and functionality serving diverse aspects of the construction processes. Channel ties restrain masonry work on to steel frames or concrete slabs. Tying frame structures made of steel or concrete to an adjoining wall is achieved with wall ties known as Frame cramps. Two-part ties are earmarked as heavy duty wall ties reserved for longer cavities requiring longer ties. Tying masonry to new brickwork or block-work requires Screw Ties. Fixing masonry to steel work requires Column Wall ties while fixing masonry to timber frame structures warrants the use of timber Wall ties. Acoustic wall ties minimize the vibrations between external and internal brickwork. Remedial wall ties used to repair damaged ties in old buildings engage: resin fix anchors to prevent inner leaf block-work from crumbling without the use of pressure and mechanical fix anchors treat inner leaf block-work with compression on assessing their ability to withstand pressure.
Aged wall ties or incorrectly installed wall ties often lead to lintel lifts, bulging brick work, and cracks in the mortar, which can be read as signs of an unhealthy outer wall and redressed after careful assessment. Expert consultation before proceeding with remedial wall tying or attempting a Wall Starter venture, which connects extension walls to existing structure using wall ties, is highly advisable and will go a long way in securing the perfect wall tie.