Brick ties are small architectural elements that are used to connect two brick walls across a narrow cavity or to bind a brick wall to a wood or steel frame. They are commonly made from pressed metal, plastic or braided wire. Their main function is to improve the strength of a brick wall by transferring some of the force applied to the wall to a second load-bearing structure. Brick ties are a cheap and effective method of reinforcing brick-and-mortar construction.
Several basic designs of brick ties exist and can be chosen based on the type of connection they are meant to create and whether they are being installed as part of the construction process or as a retrofit. Flat bands of plastic and metal can be embedded in the mortar of a brick wall to form a secure connection, allowing the other end to be connected to another structure or laid in the mortar of a second brick wall. These flat ties are often corrugated at the ends to improve their gripping power and bent into inverted "V" shapes in the middle to help shed moisture.
Brick ties might also have brackets that allow them to be nailed or screwed directly to bricks or dry mortar. By attaching a brick tie to an existing brick wall, it can be effectively reinforced long after its original construction, which can help preserve walls threatened by damage or shifting foundations. Wire ties, which can be easily adjusted to a specific length on the job site, are a popular choice for this kind of retrofit.
Many of the brick walls that are visible in a modern city are veneers or facades — thin shells of single-layer brick overlaying a structural skeleton — so brick ties are an important component of bricklaying. The use of veneers or facades reduces the amount of weight that the bricks are expected to bear, but it also makes the walls more vulnerable to wind stresses. Using brick ties to connect the brick veneer to the load-bearing structures of a building transfers some of the wind pressure to the building as a whole, keeping the bricks in place and reducing flex damage. A true structural brick wall, consisting of several layers of interlocked bricks, does not need to be bound to an inner structure for support.
Many national and local building codes require brick ties to be utilized in the construction of any single-layer brick wall. Left unsupported, such walls are vulnerable to damage from weather, earthquakes and settling foundations. Brick ties are substantially cheaper and easier to implement than an unsupported structural brick wall, so they are a common addition to modern bricklaying projects.