Concrete screws are a quick and effective solution for fixing structural and non-structural elements to cracked and non-cracked concrete, without the need for plugs or resins. Their load-bearing capacity, removability and direct installation, among other benefits, make them an attractive alternative to traditional anchoring systems.
To ensure their performance and the safety of the installation, it is essential to follow the correct installation procedure. Incorrect drilling or improper tightening can affect the performance of the fixing.
Common installation mistakes
Not preparing the hole correctly
This is one of the most important steps in the installation process. Drilling into the base material generates dust and small fragments that accumulate at the bottom of the hole. This can prevent the screw from being installed correctly, compromising the effectiveness of the fixing.
There are two ways to avoid this, both covered by the European Technical Assessment for our concrete screw range. The first is to clean the hole thoroughly using a brush and a blow-out pump to remove the debris generated during drilling. The second is to clean the hole using the drill bit itself, particularly when installing screws horizontally or downwards. To do this, drill the hole a few millimetres deeper, then insert and withdraw the drill bit three times. This removes some of the fragments and dust, eliminating the need for additional cleaning tools. Both methods are equally valid, and in either case, it is essential to follow the instructions in the technical data sheet.
Although cleaning the hole is a critical installation step in most situations, there is one scenario in which it is not essential: overhead installation. In these cases, gravity does the work, allowing the dust to fall out during drilling.
Using an incorrect tightening torque
Excessive tightening can place unnecessary stress on the anchor and cause it to break. Insufficient tightening, on the other hand, can hinder installation or prevent the anchor from being installed correctly. It is important to check the product’s technical data sheet for the recommended torque for each screw diameter.
Find out more here: How powerful should my impact wrench be for concrete screws?
Using excessively worn drill bits
If the drill bit is excessively worn, the hole in the base material will be smaller than the specified diameter. This means that more force than usual is needed to drive the screw in, which can slow down installation.
Reusing screws with worn threads
Although one of the main advantages of concrete screws is that they can be removed and reused for temporary fixings, they must not be reused if the tip is worn or damaged. If the screw passes completely through the gauge, the anchor must be discarded, as it has reached the maximum wear limit. Thread wear significantly reduces its performance.
Learn more about concrete screw reusability here: Can concrete screws be reused?
Not choosing a screw that matches the thickness of the fixture
It is important to select the right screw for the specific thickness of the fixture. For example, if a screw designed to secure a 60 mm thick fixture is used to install a 20 mm thick fixture, part of the anchor’s unthreaded section may end up inside the hole. This can cause the screw to break under torsion, particularly with smaller screw diameters.
For more technical details on the installation process and a closer look at our range, watch the concrete screw webinar presented by Héctor Sáenz, Technical Engineer at INDEX.
