How can you screw concrete?

As more and more structural elements are made of concrete, the fixing of screws in concrete is becoming increasingly important. There are different screws to consider. Below you will find detailed information about screws for concrete and the respective principles for fastening.

Fixing techniques in concrete

As more and more concrete is used for different components and components, fastening techniques are becoming increasingly important. First of all, the fastening techniques can be fundamentally different:

  • Threaded rods that are fixed with mortar in the concrete
  • Threaded rods that are bonded to concrete using high-strength injection adhesive
  • Screws that are screwed in the concrete with or without dowels

Screws with or without dowels for concrete

For many applications, screws for concrete have long prevailed that do not have to be screwed into dowels. Instead, the screw holes are pre-drilled with a percussion drill. Then these screws can be screwed directly into the concrete with a cordless screwdriver. Of course, the diameter of the pre-drilled holes is slightly smaller than the screw diameter.

Screws that are screwed into concrete without dowels

Surely one or the other reader wonders where the advantage lies over screws, which are screwed into the concrete in dowels. The widespread use of such screws was ultimately accelerated by the high energy costs as well as the specifications, which are to be complied with in the insulation according to the German Energy Saving Ordinance (EnEV).

Reduction of cold spots

A dowel is always a thermal bridge dar. With a screw that is screwed directly into the concrete, this thermal bridge is considerably lower. There is also an increased risk that condensation or condensation forms in the concrete around the dowels. This in turn does not only result in lower energy values. Moisture damage is also not visibly embedded in the concrete and can thus quickly and unhindered grow into an even greater damage pattern.

Use only corrosion-free screws

When using screws that are screwed directly into the concrete, you must pay attention to other peculiarities. Use only high quality screws that are either coated or alloyed. Otherwise, there is a high risk that the screw begins to corrode. The corrosion may continue inside the screw, where it destabilizes the concrete. Thus, a secure hold is no longer guaranteed, but also the concrete can be damaged.

Tips & Tricks

Depending on the reason you need to attach something to or in the concrete, find out about the loads that can be borne by the respective connection technology. Remember, too, that the quality of the concrete is crucial in deciding how well a screw will last in the concrete. It may then make sense to resort to systems with which you can also connect concrete with concrete (turnbuckles for concrete, for example).

Video Board: A Beginner's Guide to Attaching Things to Concrete and Brick