Masonry
Fastening in masonry - a special challenge
Masonry is the most common building material in Germany for walls in residential buildings. Masonry blocks enable flexible on-site construction with simple options. They provide a seal of the building against all climatic influences, sound, dirt, etc..
Perforated bricks are very often used for this purpose. No matter if high perforated bricks, lime sand perforated bricks, light concrete perforated bricks or special high perforated bricks filled with thermal insulation. All these bricks are usually optimized in terms of thermal insulation properties. Unfortunately, this optimization also means that the substrate is only moderately suitable for fastening high loads. Fastening systems such as bolt anchors or other metal dowels are not used because of the high expansion forces, as these could destroy the masonry block during installation. In the area of heavy-duty fastening, only an injection system can be considered. In this case, a sieve sleeve is inserted into the borehole after the hole has been drilled. This screen sleeve then serves as a carrier material for the injection mortar. The mortar can escape through the holes in the screen sleeve, but does not drip off due to its viscosity. Thus - after curing of the mortar - a very load-bearing mortar plug can be formed.
Anchorings in solid bricks (masonry bricks, sand-lime bricks, aerated concrete, Ytong ...) are much less problematic. Here, too, an injection system is recommended. However, this can be used in solid bricks without a sieve sleeve. Since the system in this case carries the loads on the bond between threaded rod - mortar - stone, special attention must be paid to the prescribed borehole cleaning. This is essential for achieving the required load capacity.
In general, the following applies to all types of heavy-duty fastening:
If the fastening is a safety-relevant fastening, i.e. in case of failure life and limb are in danger or a high economic damage is to be expected, it should only be carried out by trained specialists.
