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The Tapcon® Concrete Screw

Tapcon® is a popular brand name for concrete screws. The Tapcon® was patented in 1976 by ITW Buildex. Tapcons are the first and original screws designed to tap threads into concrete, brick or block base material.

Tapcons vs. Generic Concrete Screws

Original Tapcon® concrete screws are sometimes referred to as "blue screws". Most generic concrete screws are blue in color because the Tapcon® is blue. This makes it harder to distinguish between the two. There are many differences between Tapcon® and generic concrete screws. All Tapcons are coated with a special coating called Climaseal®. This coating is applied in multiple stages using dip-spin technology. This technology provides extra corrosion resistance and plating that is superior to what most concrete screws are plated with. This means that Tapcons will resist rusting much better than most of the generic screws on the market today. The Tapcon® is also recommended for use in ACQ pressure-treated lumber while most generic concrete screws are not. Many generic concrete screws also do not meet the specifications that Tapcons do. The one advantage of using generic concrete screws is they are less expensive. But, like with any product, you get what you pay for! The Tapcon® is unlike other concrete screws and is approved for use in seismic zones because of the exclusive HI-Lo® thread design that adds superior pull-out resistance.

Tapcon® Thread Design

The thread design of Tapcons is made through advanced thread forming technology. This allows easier installation as well as less torque required to insert the screw into the base material. The threads are referred to as "HI-Lo", meaning they allow for fast and complete dust removal, allowing the screw to tap threads consistently and provide high quality. This is a very important point because the dust that is created in the hole when the threads are cutting into the base material must be removed as fast as it is created. This ensures a smooth and consistent installation and less torque is required to insert the screw into the base material. A number of different problems are possible if the dust is removed from the hole slower than it is created. The screw will bind up in the hole preventing further insertion into the hole and/or future removal. If the screw binds in the hole and too much torque is applied the head of the screw can shear off. The lead thread is the most important of the concrete screw since it is doing all of the cutting of the base material. Therefore, the quality of the steel and the thread forming is paramount.

Hole Requirements

As with any concrete anchor, hole tolerance is critical. The Tapcon® is no different. For a 3/16" screw, the hole diameter is 5/32" and for the 1/4" the hole diameter is 3/16". The hole should always be drilled using a hammer drill and a carbide tipped bit with a matched tolerance bit meeting the diameter of the screw being used. The hole should be drilled at least 1/4" deeper than the penetration of the screw in the base material. This will insure that the screw will not bottom out before it is at the desired depth of embedment. Should the screw bottom out because the hole is not deep enough it will stop bind up and probably shear off the head.

Tapcon® Bit Lengths

Bits for Tapcon® concrete screws come in different lengths for use with different lengths of screws and fixture thickness for each size. Below is a table that shows the proper bit diameter and length for each screw.

Part Description Correct Fixture
Number   Drill Bit Thickness
  Hex Washer Head    
TCH316114 3/16" X 1-1/4" 5/32" x 3-1/2" 0 - 1/4""
TCH316134 3/16" x 1-3/4" 5/32" x 3-1/2" 1/4" -3/4"
TCH316214 3/16" x 2-1/4" 5/32" x 4-1/2" 3/4" - 1-3/4"
TCH316234 3/16" x 2-3/4" 5/32" x 4-1/2" 1-1/4" -1-3/4"
TCH316314 3/16" x 3-1/4" 5/32" x 5-1/2" 1-3/4" - 2-1/4"
TCH316334 3/16" x 3-3/4" 5/32" x 5-1/2" 2-1/4" - 2-3/4"
TCH3164 3/16" x 4" 5/32" x 5-1/2" 2-1/2" - 3"
       
TCH14114 1/4" x 1-1/4" 3/16 x 3-1/2" 0 - 1/4""
TCH14134 1/4" x 1-3/4" 3/16 x 3-1/2" 1/4" -3/4"
TCH14214 1/4" x 2-1/4" 3/16 x 4-1/2" 3/4" - 1-3/4"
TCH14234 1/4" x 2-3/4" 3/16 x 4-1/2" 1-1/4" -1-3/4"
TCH14314 1/4" x 3-1/4" 3/16" x 5-1/2" 1-3/4" - 2-1/4"
TCH14334 1/4" x 3-3/4" 3/16" x 5-1/2" 2-1/4" - 2-3/4"
TCH144 1/4" x 4" 3/16" x 5-1/2" 2-1/2" - 3"
TCH145 1/4" x 5" 3/16" x 6-1/2" 3-1/4" - 4"
TCH146 1/4" x 6" 3/16" x 7-1/2" 4-1/4" - 5"
  Flat Counter Sunk Phillips    
TCF316114 3/16" X 1-1/4" 5/32" x 3-1/2" 0 - 1/4""
TCF316134 3/16" x 1-3/4" 5/32" x 3-1/2" 1/4" -3/4"
TCF316214 3/16" x 2-1/4" 5/32" x 4-1/2" 3/4" - 1-3/4"
TCF316234 3/16" x 2-3/4" 5/32" x 4-1/2" 1-1/4" -1-3/4"
TCF316314 3/16" x 3-1/4" 5/32" x 5-1/2" 1-3/4" - 2-1/4"
TCF316334 3/16" x 3-3/4" 5/32" x 5-1/2" 2-1/4" - 2-3/4"
TCF3164 3/16" x 4" 5/32" x 5-1/2" 2-1/2" - 3"
       
TCF14114 1/4" x 1-1/4" 3/16 x 3-1/2" 0 - 1/4""
TCF14134 1/4" x 1-3/4" 3/16 x 3-1/2" 1/4" -3/4"
TCF14214 1/4" x 2-1/4" 3/16 x 4-1/2" 3/4" - 1-3/4"
TCF14234 1/4" x 2-3/4" 3/16 x 4-1/2" 1-1/4" -1-3/4"
TCF14314 1/4" x 3-1/4" 3/16" x 5-1/2" 1-3/4" - 2-1/4"
TCF14334 1/4" x 3-3/4" 3/16" x 5-1/2" 2-1/4" - 2-3/4"
TCF144 1/4" x 4" 3/16" x 5-1/2" 2-1/2" - 3"
TCF145 1/4" x 5" 3/16" x 6-1/2" 3-1/4" - 4"
TCF146 1/4" x 6" 3/16" x 7-1/2" 4-1/4" - 5"

Embedment Requirements

Tapcons require a minimum embedment of 1" and a maximum embedment of 1-3/4". If a user embeds the screw less than 1", the holding values will be diminished. Under embedment should be avoided because the true holding value would be unknown. Trying to embed the screw deeper than 1-3/4" will cause the screw to bind in the hole to the point where the screw will not go in any further. Binding in the hole can also cause the screw to not be able to be removed or the head will shear off. The harder the base material, the less the maximum embedment should be. When the screw is inserted into the hole, the lead thread is doing all of the cutting of the base material. The lead thread will lose its ability to cut into the base material if it has done drilled more than 1-3/4" of embedment or the base material is extra hard or abrasive. Once the screw binds in the hole and too much torque is applied, the head of the concrete screw will shear off.

Determining the Length of Tapcon® to Use

To determine the length of the Tapcon® needed, add the thickness of the material to be fastened plus a minimum of 1" and a maximum of 1-3/4". All of the screws are measured from under the head. Let's say you want to fasten a 2x4 to concrete. The 2x4 is 1 1/2" thick so adding a minimum of 1" = 2 ½". Adding a maximum of 1-3/4" to a thickness of 1 ½"= 3 ¼". So the range of lengths for this screw is 2 ½"- 3 ¼". Tapcon® concrete screws come in lengths of 2-3/4" and 3-1/4". The 2 ¾" concrete screw would be the proper choice in this situation as the embedment would be 1 ¼".

Installation of Tapcons

The installation of a concrete screw can be completed in four steps. The steps are as follows:

  1. Using a hammer drill and a carbide tipped masonry bit (in the proper size), carefully drill a pilot hole 1/2" deeper than the recommended anchor embedment.
    "** Important Note: 1/4" diameter Tapcons use a 3/16" bit and 3/16" diameter Tapcons use a 5/32" bit.
  2. Clear the hole of all debris as the hole is being drilled.
  3. Insert the pointed end of the concrete screw through the hole and into the base material.
  4. Using a standard drill with the appropriate hex or Phillips socket, drive the concrete screw carefully into the pre-drilled hole until the screw is fully seated.
    ** Important Note: Be careful not to over-tighten the Tapcon® during installation. This will cause it to spin in the hole and strip the threads.

Applications for Tapcons

Tapcons are versatile as they can be used in concrete and brick as well as block base material. They are available in diameters of 3/16" or 1/4" with lengths from 1-1/4" to 6". The different lengths allow for materials [in thicknesses up to 5"] to be fastened. This wide range allows these concrete screws to be used in many applications such as studs, plywood, electrical boxes, door bucks and more.

Approvals for Tapcons

Tapcon® screws have been tested and are proven to have excellent holding values. They have earned approvals from a number of industry's building codes, such as: City of Los Angeles, Miami-Dade Count, FL and SBCCI.

Tapcons® Head Styles

An important feature of these concrete screws is that users have a choice of head style. There are two head types available: the hex slotted washer head and the countersunk flat head Phillips. Each has different requirements that must be considered when working with each style:

  • The hex head requires a 1/4" nut setter for the 3/16" diameter and the 1/4" screw requires a 5/16" nut setter. The hex head should be used in all applications where the head does not need to be countersunk in the material.
  • The flat head countersunk Phillips require a #2 bit tip for the 3/16" and the 1/4" screw requires a #3 bit tip. The flat head screw is used in applications where the heads of the screws need to be countersunk into the material being fastened.



 

As with any anchoring project, it is important to keep safety in mind and follow instructions carefully. Always remember to wear safety goggles, handle all tools with extra care and follow all technical specifications. This article is meant to serve only as a basic explanation of concrete fasteners. Always refer to manufacturer's instructions or consult a contracting expert during any anchoring project.

Article Written By:
Mike Pistorino, Vice-President Operations

 

 

 

 


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