Concrete Screw
Concrete screws are specialty fasteners designed to anchor into concrete, brick, or block by cutting threads into a predrilled hole. Instead of using a separate expansion mechanism, the hardened threads bite into the base material to create holding strength. They are commonly used for attaching electrical boxes, fixtures, brackets, sill plates, and light to medium duty hardware to masonry surfaces.
Concrete screws require the correct pilot hole diameter and depth, typically drilled with a masonry bit, to achieve proper engagement and reduce the risk of stripping. Their holding performance depends on base material condition, embedment depth, edge distance, and spacing from other anchors. For best results, clean the hole of dust and debris, drive the screw straight, and avoid over tightening, since excessive torque can damage the threads in the concrete and reduce holding strength.