When wall ties are missing or corroded or brick headers are broken, the exterior brick or portions of it can fall from the building. A common but expensive repair is to replace part or all of the brick. Reanchoring the brick to the backup costs much less and is just as effective if the conditions that lead to the failed wall ties are corrected too. ADHESIVE SYSTEMS Most adhesive anchors are installed in similar ways, using an epoxy or polyester adhesive. First you drill a hole, then brush and blow out the hole to remove drilling dust. Fill a steel screen tube with the adhesive and insert the filled screen in the hole. Then, while holding the tab attached to the end of the screen, insert a steel rod, turning it slightly to ensure a good bond. In the last few years, injection guns have become available that ensure proper proportioning and mixing of the two components needed to make polymer adhesives. POLYESTER OR EPOXY? This new injection equipment has made epoxies, which are more sensitive than polyesters to improper proportioning, much more reliable for anchoring than they once were. But polyesters are still viable and widely used. MECHANICAL SYSTEM Expansion anchors consist of two expansion sleeves, one for the backup and one for the facade, connected by a flexible wall tie. To install an expansion anchor, you drill a hole in the mortar joint of the outer wythe, typically at the T-intersection of a head and bed joint.