Wasps like to look for sheltered niches to nest. Small gaps in natural stone walls or isolation cavities are ideal breeding grounds for them. However, their colonization can still disturb us humans. Getting rid of them is not always advisable, however.
Wasps in masonry can be critical, but don't have to be
Problematic and unproblematic settlements
Whether the nesting of wasps in masonry is critical for people or the structure of the building depends on the respective location. The different wasp species that live in our country require different nesting conditions and therefore settle in different types of masonry. For example, what they consider welcome shelters are:
- Gaps in natural stone walls
- Cavities between the foundation masonry and the outer cladding
For smaller gaps between coarse natural stone walls that are not or only halfway mortared, solitary wasp species in particular should be heated. These include, for example, clay or potter wasps. In natural stone wall crevices they find ideal space and protection for their comparatively small nests, which consist of only a handful of brood chambers.
In this case, the best thing to do is simply wait for the breeding phase, which only lasts from spring to autumn anyway. As a rule, the stone wall does not suffer any significant damage from the nest, and the few animals of a solitary, shy wasp should not be a major nuisance.
The situation is different with the social wasp species, especially with German and common wasps. It is also these species that most of us know as typical wasps, since, in contrast to the large remaining proportion of wasp species, they seek proximity to humans. These social wasps form large colonies and require correspondingly more space for their nests. Since they are also so-called dark cave nesters, the cavities provided for insulation between the foundation masonry and the outer cladding of residential buildings offer them the best nesting conditions.
If wasps nest here, that's more of a problem. Because if the nest is big and the wasps are disturbing, it is difficult to get to it. It is true that the insulating material and masonry are only slightly damaged and after one season the colony has disappeared. If the old nest remains in the cavity, hardly any other wasps will settle there in the following year.
What they shouldn't do is plug entry holes. The wasps are unnecessarily tormented by this and will also try to eat their way out through the insulation material - the material damage will therefore increase, and you may also close ventilation openings that are important for the wall construction.