Securing heavy loads to concrete is one of the most critical phases on a construction site. Whether it involves steel columns in an industrial hall, heavy HVAC supports, or warehouse shelving, a fastening failure can lead to serious safety hazards and significant financial losses. Modern construction requires installers and designers to have an increasingly deep understanding of the differences between fastening methods, because concrete is a living material with its own limitations for fasteners.
Traditional wedge anchors and hammer-set anchors have dominated the market for decades, but the technical development of concrete screws has made them a serious alternative in many heavy-duty applications. However, the choice is not always straightforward. Professionals must consider the concrete strength class (e.g. C20/25 or C50/60), cracked or non-cracked concrete, edge distances, and the dynamic loads involved in installation. The right choice optimizes not only safety, but also labor time and costs.
In this guide, we take an in-depth look at the technical differences, installation requirements, and selection criteria for concrete screws and anchors. If you need help finding the right solution for your specific project, you can contact our experts and request an assessment today.
Concrete Screw – A Modern and Flexible Choice
Concrete screws have become the primary choice for many professionals, especially in medium-duty and heavy-duty installations. Their popularity is based above all on installation speed and the fact that they do not create significant expansion pressure in the concrete. Unlike traditional anchors, a concrete screw does not attempt to expand the drilled hole from the inside, which allows fastenings to be placed closer to the edge of the structure and with smaller spacing between fasteners.
The Technical Operating Principle of a Concrete Screw
Installing a concrete screw is based on the threads cutting directly into the concrete. The tip of the screw usually has hardened cutting teeth or a specially shaped thread that "mills" matching threads into the drilled hole. When the screw is tightened, it forms a shape-locking connection with the concrete throughout its embedment depth.
This method is especially effective in cracked concrete (ETA Option 1), where hairline cracks in the tension zone could weaken the holding power of a standard expansion anchor. A concrete screw maintains its strength because its threads bite deep into the material. However, it is important to remember that although a concrete screw can be removed, reusing it in the same hole under heavy loads always requires the manufacturer’s approval and often inspection of the hole with a separate gauge.
Fast installation process
Installation is done directly with an impact wrench. Retightening with a torque wrench may not be required for all models, which significantly speeds up series installations.
Versatile head styles
Available in hex head, countersunk head, and internally threaded versions (e.g. M8/M10), making them ideal for many different structures.
Wedge anchors and drop-in anchors – The cornerstones of steel construction
Although concrete screws are gaining ground, wedge anchors and drop-in anchors still have a firm place. Their strength lies in traditional, proven performance and cost-effectiveness in high-volume applications where the installation base is non-cracked concrete and edge distances are sufficient.
When should you choose an anchor instead of a screw?
Wedge anchor performs best in through-fastening applications, where the part to be fixed is placed in position and the hole is drilled directly through the part into the concrete. It is highly reliable in heavy steel structures, such as fastening column base shoes or machine bases. Its operation is based on an expanding sleeve during tightening, which locks the anchor into the drilled hole through friction and pressure.
Drop-in anchor, on the other hand, is an internally threaded anchor expanded by driving it in. It is a standard solution in building services: for suspending threaded rods, pipe supports, and sprinkler systems from concrete slabs. The advantage of a drop-in anchor is that the bolt or threaded rod can be removed and replaced, even though the anchor itself remains permanently embedded in the concrete.
Critical steps: Drilling and cleaning
One of the most common mistakes on job sites is neglecting to clean the drill hole. Even though a concrete screw “cuts” space for its threads, drilling dust at the bottom of the hole can prevent the screw from reaching the required embedment depth. This is even more critical for wedge anchors, where friction depends on clean surface contact with the concrete.
A professional rule of thumb is the 2x2x2 cleaning method: two blows, two brushings, and two more blows. If dust remains in the hole, the fastener may “spin out,” meaning it starts turning freely without gripping, or it may jam halfway in. Vacuum drill bits are also available today, removing dust directly during drilling—this is a recommended investment when you have hundreds of installations to complete. Explore ProMart’s wide range of power tools and drill bits to maximize efficiency.
ETA approval and regulations – Don’t compromise on safety
In public construction and load-bearing structures, only ETA-approved (European Technical Assessment) fasteners must be used. ETA approval is not just a “stamp”; it provides the fastener’s exact technical values under standardized conditions.
- ETA Option 1: Approved for use in cracked and non-cracked concrete (tension and compression zones).
- ETA Option 7: Approved only for non-cracked concrete (typically compression zones, such as floors).
- Fire rating (R120): Indicates the fastener’s load-bearing capacity in a fire situation, in minutes. For example, supports for smoke extraction systems invariably require a high fire rating.
- Seismic approval (C1/C2): Required in applications where earthquakes or strong vibration must be taken into account.
Installation Speed and Total Project Costs
When calculating the total installation cost, the purchase price of the fastener alone tells only part of the story. A concrete screw often has a higher unit price than a wedge anchor, but its installation process is significantly faster. Concrete screws save time by reducing work steps: there is no need for final tightening with a torque wrench, and often no need to hammer the anchor into place separately.
On the jobsite, installation speed can improve by as much as 30–50%. On large-scale projects, such as racking installations in logistics centers, this can mean savings of thousands of euros in labor costs. In addition, the removability of concrete screws reduces the time spent correcting installation errors and makes it easy to dismantle temporary structures, such as formwork or work platforms, without damaging the concrete.
Summary: How to Make the Right Choice
Choosing the right concrete fastener means balancing technical requirements, safety, and cost-effectiveness.
- Choose a concrete screw when you need speed, are installing close to an edge, or are working in cracked concrete.
- Choose a wedge anchor for traditional, heavier steel structures in non-cracked concrete when maximum cost-efficiency is the goal for large-volume installations.
- Choose a drop-in anchor when you need a reliable internal thread for threaded rods and MEP suspensions.
ProMart is the professional’s partner, offering not only high-quality fasteners but also the expertise needed to make the right choice. We help you ensure that your project meets all regulatory requirements and is completed on schedule.
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