Slit a wall


Slitting a wall is the typical way to retrofit electrical installations, for example. However, slitting affects the load bearing capacity of a wall. Therefore, there are specifications that must be adhered to.

Requirements for slitting walls

The slitting of walls takes place in interior walls, which were built in masonry, so in wet construction. However, it is not allowed to simply slit. The requirements and specifications for slitting walls are given in DIN EN 1996-1-1. The thickness of the inner wall is of crucial importance.

For non-load-bearing walls, these guidelines should also be applied

However, DIN EN 1996-1-1 concerns load-bearing walls. For non-load-bearing walls, there are no specific requirements. However, it is generally accepted that the requirements of DIN EN for load-bearing walls should also be applied to non-load-bearing walls.

Distinction of slits in the wall

Then it has to be considered that different slits can be made. The following alignments when slitting are permitted:

  • horizontal slots
  • vertical wall slots

It should be well known that diagonal may not be slit, as installations should not be so misplaced.

The slot depth

The usual slot depths are between 10 and 30 mm.

Horizontal slitting of walls

First of all, horizontal slits should not be drawn more than 40 cm above or below a raw slab. In other words, this means a maximum of 40 cm below bare floors, ie without panels, and a maximum of 40 cm above the bare floor, ie also without coverings. Pad thicknesses must therefore be subtracted from the 40 cm.

Basically, horizontal slitting is the biggest problem because the wall cross-section is reduced over the entire length of the slit. In particular, the load capacity thus suffers under horizontal slots in particular.

Therefore, the wall thicknesses are decisive, if ever allowed to be slotted. To distinguish here are again relatively short slots that are shorter than 1.25 m, and those that exceed this length. Up to a horizontal slit length of 1.25 m, the wall must be 15 cm thick. Horizontal slots, which are longer or over a whole wall length, require a minimum wall thickness of 17 cm.

In addition, walls may only be slit on one side. An exception to this is when the wall thickness is at least 24 cm and the slot depth of the two slots is a maximum of 10 mm.

Vertical slots

Vertical slots in the wall can be made from a wall thickness of 12 cm. The distance to wall openings, openings and recesses must be at least 11.5 cm. If several wall slots needed side by side, the minimum distance between two slots is at least at the basic slot width. Overall, several vertical slots next to each other must not exceed a width of 2 m.

Tips & Tricks

The various dimensions can be reconciled via DIN EN 1996-1-1 and relevant table manuals. In these tables, wall thicknesses, slot widths and slot depths are set in relation to each other so that, for example, the maximum slot depth can be taken.

Product Image: Pawel_Brzozowski / Shutterstock


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