How to Use Tapcon® Concrete Screws Effectively
Published by Robert Carlisle on Jul 31st 2009
Concrete screws are the generic name for a specially manufactured screw that taps threads into concrete, brick or block. The threads are hardened to cut the base material. The threads are created with a special design that allows for removal of the dust that is created while cutting the threads.
Buyers need to be aware that all concrete screws are NOT created equal. Tapcon® is a brand name of the concrete screw that is made by the original manufacturer and is an American made product. All concrete screws that are manufactured generically do not meet the same standards of thread design, rust resistance, and ease of insertion. Concrete screws are not the answer to all fastening applications and will not work in all applications for numerous reasons. When used correctly in suitable applications following correct installation instructions, Tapcons will be 100% effective.
Unsuitable Concrete Screw Applications
1. When the base material is sandy or made up of loose particles, concrete screws will not be able to tap threads. This will prohibit the screw from being able to hold tight to the base material.
2. When the base material is too hard, it will prevent the threads from cutting into the base material. The concrete screw will not penetrate the hole in the base material and will not be able to even begin to tap threads.
3. When the base material is too abrasive, the concrete screw will not be able to cut threads to a depth that meets minimum embedment requirements. If the lead thread does all of the cutting of the base material, it will wear down to a point where it will no longer cut the material. The screw will stop or shear off before the screw is tight against the fixture being fastened.
4. When the concrete screw is embedded deeper than the maximum embedment depth, it will cause the screw to either stop or shear off. Maximum embedment depth of a concrete screw is 1-3/4" and the total length of the threads on a concrete screw is 1-3/4". Do not attempt to embed a concrete screw deeper than the maximum embedment value.
How to Install Concrete Screws
Once it has been determined that a concrete screw is the proper fastener to use in an application and that the base material is suitable, follow these installation instructions for success:
1. Select the proper diameter required for the specific application. The diameter of the concrete screw is determined by the holding values needed for the particular application. Below is a chart for the standard blue Tapcon® screws' holding values in concrete. Note: If you are not using Tapcon® brand concrete screws, these holding values will not apply.
Tension & Shear in Normal-Weight Concrete
| Anchor Diameter | Embedment Depth | Tension 2000psi |
Shear 2000psi |
Tension 4000psi |
Shear 4000psi |
Tension 5000psi |
Shear 5000psi |
| 3/16" | 1" 1-1/2" 1-3/4" |
6000 1090 1450 |
720 860 870 |
650 1090 1460 |
720 860 990 |
800 1220 1730 |
860 860 990 |
| 1/4" | 1" 1-1/2" 1-3/4" |
750 1380 2020 |
900 1200 1670 |
800 1820 2380 |
1360 1380 1670 |
950 2170 2770 |
1440 1670 1670 |
Tension & Shear in CMU (1" embedment)
| Anchor Diameter | Tension (lbs.) | Shear (lbs.) | ||
| Light Weight | Medium Weight | Light Weight | Medium Weight | |
| 3/16" | 220 | 340 | 400 | 730 |
| 1/4" | 250 | 500 | 620 | 1000 |
2. Select the proper length of concrete screw needed. The length of the concrete screw is determined by adding the thickness of the material to be fastened to the minimum embedment of 1" and a maximum embedment of 1-3/4". This will provide the minimum and maximum length of screw that can be used.
Example:
A 2x4 needs to be fastened to concrete. The 2x4 is 1-1/2" thick. Adding the 1-1/2" of the 2x4 plus a minimum of 1" embedment= 2-1/2". This would be the minimum length of screw that can be used. The maximum length would be 1-1/2" + 1-3/4"= 3-1/4", the maximum length of screw that can be used. The proper length could be either the 2-3/4" or the 3-1/4" length concrete screw. The 3-1/4" screw would be right at maximum embedment and depending on the abrasiveness of the base material, may be too long. The 2-3/4" length is the most commonly used length for this type of application because it is 1/4" deeper than the minimum embedment depth.
Below is a chart with all of the sizes of Tapcons that are available and a column with the thickness range for all sizes:
| Part Number | Description | Correct Drill Bit | Fixture 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" X 2-3/4" |
| TCH3164 | 3/16" X 4" | 5/32" X 5-1/2" | 2-1/2" X 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" X 2-3/4" |
| TCH144 | 1/4" X 4" | 3/16" X 5-1/2" | 2-1/2" X 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" X 2-3/4" |
| TCF3164 | 3/16" X 4" | 5/32" X 5-1/2" | 2-1/2" X 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" X 2-3/4" |
| TCF144 | 1/4" X 4" | 3/16" X 5-1/2" | 2-1/2" X 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" |
3. Using the correct size bit for the diameter and length of screw being used, drill a hole in the base material using a hammer drill. It is critically important that the proper diameter of bit is used when drilling holes for concrete screws.
If installed properly in suitable applications, concrete screws are extremely effective. Tapcons shouldn't be confused with generic concrete screws since Tapcons are of higher quality and meet higher standards. Tapcons are a great screw to use in many concrete fastening projects.