Anchors and Concrete Screws

Anchors and Concrete Screws

Self Tapping, Expansion Anchors and More for Use with Masonry Materials

Masonry Anchors are used to attach fixtures to hollow walls, concrete or other masonry materials. There are many different kinds of anchors, each with different functions or methods used to anchor themselves to materials, most involve some form of expansion anchoring or threading the material being fastened into. Most notable are Masonry Anchors consisting of Wedge, Sleeve, and Concrete Screws.

Concrete Screws

Concrete screws, also known as masonry screws or anchor screws, are screws used to secure materials to concrete, brick or block. Made for light duty fastening, concrete screws are quickly becoming a popular way to anchor materials to masonry. These screws are hardened and coated in a blue coating to protect them, which is part of the protective coating which extends the corrosion and rust resistance of the screw, making them suitable for exterior and long-lasting applications. Due to this unusual color these screws have also become known as blue screws. One of the greatest benefits of concrete masonry screws is that they can be easily removed if necessary unlike expanding masonry anchors.

Concrete screws come in 3/16" and 1/4" diameters. The 3/16" screws are considered good for general use applications and where the concrete is soft. If the screws have a problem drilling into the material or the load is heavy, 1/4" concrete screws will be a better fit. As a rule of thumb, the harder the material is the stronger the hold will be. They are hardened and tap their own threads during installation. Anchor screws are mainly used to hold metal or wood to concrete. Concrete screws are available in both Phillips flat head and Hex Washer head varieties. The Phillips version is often used when a flush head is needed but the hex washer head is easier to drive. Anchor screws need to be a minimum of 1" embedded in the masonry material to be considered properly installed.

Installing Concrete Screws

To install blue screws, first measure the drill bit against the masonry screw. The hole needs to be deep enough to sit the entire screw length. It is also recommended to drill slightly further than the screw length to allow room for debris from the drilling. Next, drill a hole using a hammer drill and masonry drill bit. Once the hole is at the appropriate depth, try to remove as much debris as possible. Once the hole is clean, install the screw using a drill/driver. Although not entirely necessary, it is recommended to drive the last few turns by hand to prevent stripping the screw.

Once a screw is removed from a hole, it should not be reinstalled into the same hole. Each time a screw is reinserted it will tap new threads causing the overall integrity of the hold to weaken. It is important not to drive the screws at high speed. Low to medium speeds will allow the self tapping threads to form threading in the material. If the screw is spinning loosely in the hole, a plastic expansion anchor can be added to provide the screw with threading points.

Concrete Sleeve Anchors

Masonry Sleeve Anchors are used for Hollow Concrete Masonry units such as concrete or cinder blocks. Concrete sleeve anchors consist of a threaded stud with an outwardly flared cone-shaped end, with a nut and a washer on the end. Tightening of the nut pulls the stud end into the expander sleeve, wedging it outwards and locking the anchor into the base material. Concrete Sleeve Anchors are used to anchor and secure material and equipment to concrete masonry surfaces. Sleeve anchors are inserted into pre-drilled holes and then they can be expanded for a secure fit, anchoring objects to the concrete, brick, or block.

Concrete Sleeve anchors work on the true expansion principle: turning the nut on the sleeve anchor pulls the working end of the anchor up through the sleeve, expanding the anchor and causing the anchor to secure itself to the material.