If you experience an air gap when drilling into your cavity brick walls, this could indicate missing or damaged wall ties that need replacing to avoid damp in the home. Replacing them quickly and effectively is an easy way to stop damp in its tracks.
Typically, two and a half wall ties should be installed per square metre in a staggered pattern with 900mm horizontal and 450mm vertical centerlines, except where openings, unreturned/unbonded edges or vertical expansion joints exist – these should be within 225mm of their edge.
Stainless steel
Wall ties made from stainless steel are extremely resilient and won’t rust or corrode, as well as resist moisture accumulation within cavities. It should be noted, however, that different varieties of stainless steel possess different properties; which one you select depends on your operating environment and should possess suitable resilience, toughness, formability and weldability characteristics.
Cracked lintels around doors and windows is one of the main indicators of wall tie failure, so it is advisable to seek professional assistance from a wall tie surveyor as soon as cracks appear in these lintels. They will use specialist equipment and detectors to assess your walls and ties’ conditions.
There are various masonry and brick/block wall ties available, depending on building size and construction type. Standard types, as well as composite types made with basalt fibres set into resin matrix are among the options available, with composite types particularly useful in ultra-low energy construction to reduce heat loss via “thermal bridging.”
Double drip feature
Stainless steel wall ties designed with double drip features can prevent moisture traveling across masonry, while their retaining clip secures insulation firmly in place. They’re suitable for use with face and cavity insulated blocks alike and meet PD6697 and Approved Document A requirements to separate walls up to 10 metres high.
Stainless steel wall ties are the go-to choice due to their ability to resist corrosion from water and cement, and are available in different diameters and lengths to meet various applications. Their anodised finish also offers long-term corrosion protection.
Mechanical remedial ties are used to replace wall ties that have failed, by installing them at regular intervals with holes drilled at regular intervals in brickwork. They consist of threaded stainless steel rods equipped with neoprene expanders at each end which are threaded through holes and tightened using a cordless drill to grip their substrate and secure its position.
Long-lasting
These ties are constructed of stainless steel to withstand corrosion for the life of your building, saving both money and repairs due to lower maintenance costs and repairs.
Wall ties should be installed after both leaves of a cavity wall are constructed so that they are fully integrated into its structure. This method reduces risk of protrusion through insulation or damaging it and also ensures they are completely submerged under fresh mortar, preventing moisture from reaching them.
The type of wall tie necessary can depend on factors like building height, intended use, structural format and exposure to wind. Selecting an appropriate cavity wall tie is critical in maintaining structural integrity of buildings; staggered spacing is best with no closeness near any opening if unreturned; additionally drilling through hidden services could result in stress fractures in masonry structures.
Easy to install
Cavity wall ties are installed by bricklayers as part of their masonry construction process, and can be utilized with various construction methods including stretcher bond, English bond and Flemish bond. Furthermore, these ties come in multiple lengths and diameters to suit full fill cavities as well as partial fill cavities, featuring multi-drip features to prevent moisture migration along their lengths and diameters.
Choice of cavity wall ties depends upon construction type, building size and height, location of property as well as budget considerations. When considering remedial costs such as surveys, installations and any subsequent retesting costs it is also important to keep this in mind.
Remedial cavity wall ties are designed to replace old or corroded ties and help stabilize inner and outer brick walls. Their installation requires no special tools – simply drill into the existing walls using an SDS adaptor in hammer mode only mode, with their helical end undercutting into their substrate to hug it securely.