Reinforcement fabric on exterior plaster


If old exterior plaster is to be renovated or plastered again, a widespread opinion among do-it-yourselfers is that reinforcing mesh is always good. That is not so. Whether and when reinforcement fabric can be applied to exterior or facade plaster or not, you can read here; In addition, what else is to be considered in the old exterior plaster.

Determine the condition of the external plaster

In particular, if cracks or crumbled areas can be found in the old facade plaster, do-it-yourselfers repeatedly come to the conclusion that in addition to reinforcing plaster, they also need to use a reinforcing mesh to prevent this problem. But that is not necessarily so. First, any previous damage must be checked and evaluated:

  • solid or growing cracks in the exterior plaster
  • Consistency of the old plaster
  • Properties of the external plaster such as absorbency

Find cavities and no longer adherent plaster

With a hammer, first the entire plaster is knocked off. The aim is to discover areas in which the plaster no longer adheres. This can also affect areas in which there are no cracks, but then cavities. Are cracks in the old exterior plaster, it does not help here to cut off the old plaster only extensively.

Possible causes of cracking in exterior plaster

Rather, it is also about the question of why cracks exist at all. Depending on the age of a building as well as the possible quality in previous renovations or also in the former new construction, the composition of the masonry must be examined.

Cracks often form when the masonry consists of different building materials such as brick or brick and limestone. Both building materials have completely different thermal behavior, which leads to a significantly increased tendency to crack.

Check the consistency of the facade plaster

Another decisive factor is the general condition of the exterior plaster. Depending on the composition, quality and weathering this is either still very strong, but perhaps also very porous. Scrape with a screwdriver tip over the plaster. If the screwdriver does not penetrate deeply or not at all into the facade plaster, the consistency is sustainable. Otherwise, the old exterior plaster must be knocked off.

The absorbency of the old exterior plaster

Then the absorbency of the old exterior plaster is checked. Here it needs experience. Basically the following applies: Too much absorbent plaster leads to the need for deep ground, barely absorbent ground to primer.

However, before you provide the external plaster with a suitable primer, the facade with a steam cleaner is to be cleaned properly. Then you have to wait until the facade is dry again. Plan the re-plastering of the exterior plaster accordingly in the season and also according to weather conditions.

Various techniques for reinforcing exterior plaster

When using a reinforcement, there are various options that depend on the individual circumstances. Use only reinforcing plaster on which the later plain plaster comes. Armierungsputz with reinforcing fabric, where there is reinforcing fabric, which remains in the plaster and other, which is removed after drying again.

In addition, the reinforcement can come in the conventional facade plaster. In the house journal, you will find numerous contributions that show how to proceed when plastering the façade and what to pay attention to when it comes to plastering and reinforcing.

Tips & Tricks

For more information on the different options, see "plastering reinforcement fabrics".


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