There are now many companies that offer similar products to the original ITW/Buildex Tapcon® brand of concrete screw. Generic imported concrete screws are now also readily available and offer excellent quality but at a much lower cost. Most concrete screws sold today are blue in color to resemble the original Tapcons with the distinct blue corrosion resistant Climaseal® finish.
Concrete screws are available with two head styles: hex washer and countersunk flat head. The hex washer head is slotted while the countersunk flat head has a phillips drive. Both are available in lengths from 1-1/4″ up to 6″ to accommodate the varying thickness of different materials to be fastened.
Concrete Screw Embedment
The maximum embedment into the substrate suggested for concrete screws should be no deeper than 1-3/4″ because the thread effectiveness to tap into the substrate deteriorates as the lead threads begin to wear. Concrete screws also have a minimum embedment of 1″ into the substrate in order to reach maximum effectiveness.
Concrete Screw Sizes
Tapcon® Sizes are quite standard and limited compared to most other screws. Diameters are 3/16" and 1/4" - Lengths range from 1-1/4" to 6" - The minimum length of concrete screw is easily calculated. Add 1″ to the thickness of the material being fastened in order to achieve the minimum embedment of 1″. To determine the maximum length of screw, add 1-3/4″ the thickness of the material to be fastened. Hex head concrete screws are measured from surface under the head to the tip of the screw. Flat head screws are measured from the flat surface of the head to the tip of the screw.
Drill Bits for Concrete Screws
Concrete screws require that a hole be drilled into the substrate before the screw can tap threads. A proper hole size is critical for the screw to sit properly and thus requiring the use of a proper drill bit so that specific tolerances are met. A carbide bit meeting ANSI standards is recommended and should be used in combination with a hammer drill so the proper size and shape hole is formed. The hammer motion breaks up the masonry material and the rotation removes the dust from the hole ensuring the hole meets proper tolerances for maximum grip strength.
Depth of Hole for a Concrete Screw
The drilled hole in the substrate must be a minimum of 1/2″ deeper than the penetration depth of the screw. This will allow ample space for debris created during the tapping process to collect and will ensure that the screw will not bottom out in the hole.
Concrete Screw Installation