Can wasps under the roof, cause damage to the facade and insulation?

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Wasps under the roof

Wasps also like to build their own home on or in their own home. Can this lead to serious damage to the house or consequential damage to the building fabric? Is a peaceful coexistence of humans and wasps possible in this immediate vicinity? If not, how can you get rid of them? Or preventively, what can you do to prevent them from settling down? Some basic knowledge about wasps, wasp nests, roofs and facades can help to act appropriately in individual cases.

wasp species

The 4000 different species are assigned to the family of the flat wasp wasps (Vespidae). Here again there are two subfamilies, the solitary wasp wasps and the real wasps.
The subfamily of the wasps is again divided into three groups: hornets, long-headed wasps and short-headed wasps. The species of long-headed wasps are hardly annoying to us because they are not so close to human beings. In addition, they are short-cycle and disappeared from the scene at the end of August. They usually build free-hanging nests in trees, shrubs and occasionally under a roof ledge. But this construction is unproblematic for the building fabric. These are usually these types:
  • Medium wasp
  • Saxon wasp
  • forest wasp
  • Norwegian wasp
The three species of wasps that we usually deal with are: the German wasp (short-headed wasp), the common wasp (short-headed wasp) and the hornet.

way of life

Almost all real wasps form states, including the common and the German wasp. They build nests and have a queen. Her fondness for tidying up a good deal of sweets towards the end of the summer makes her annoying to people.


These two species like to build their nests in secret and close to us. Popular nesting sites are the compost heap, in the ground, under the roof or even in facades or shutter boxes. Their states can consist of up to 7,000 individuals.
The material they use, the wasp paper, is made of wood. For this purpose, they mix mainly rotten or dry wood with their saliva, thereby forming small beads. These are then built into brood combs. The dried out material is extremely hard and resistant.



Such a wasp life is very short. A young queen starts in the spring to start her state:
  • Queen builds a few honeycombs
  • lay eggs and nourish them
  • the first workers hatch
  • Workers now take over further nest building and the feeding of other larvae
  • the larvae are fed exclusively with a porridge made from insects
  • Queen is then almost only responsible for the oviposition
  • the nest is growing
  • in late summer, drones hatch (fertile males)
  • and young queens
  • the drones die after mating
  • The young queens fall under rotten wood in winter rigor
  • the old queen dies in October / November with her entourage
Every year a young queen builds a new nest. Old buildings are no longer occupied. However, existing old nests can cause the queen to settle near by their smell.

Damage - benefit

Before the substance of the hive is concerned, a brief overview of what the expected damage can be and whether these pest spirits (in the main: short-headed wasps, hornets) can not be useful in any way. What happens when hornets, common and German wasps build their nests directly on, in the house or in the immediate vicinity of the house:


  • Removal of material for access
  • Cuttings of material for nest building
  • Nest can block jalousie
  • aggressive behavior due to too close proximity of humans to the nest (<2 to 3 meters)
  • Discoloration, corrosive, smelling feces (with hornets)


  • eat pests, including aphids, tree pests and mosquitoes
  • eat carrion, dead animals
  • pollinate the domestic flowers

Roof tiles, attic

Wasps wood

Especially older houses and houses, which are under monument protection, offer delightful opportunities for seeking queens, exactly here to build their nest. The roof tiles are not final, they are usually irregular, because they are handmade and thus grant the wasps inlet and shelter. Here it is dark and protected.
Also, the insulating material, if it is accessible and perhaps already porous, can not stop a young queen willing to build, gnawing through it. After all, a dry, sheltered spot lures under the roof, in the loft or attic.
If a roof truss made of dry, untreated or even rotten wood is added, this seems to be a paradise for nesting, as the building material is included in the delivery.
These facts suggest that in most cases it is not the wasps themselves that cause the most damage here.They are more likely to take advantage of opportunities, or any existing vulnerabilities, to build their nest.

Facade, insulation

Basically, the façade is the same as the roof. Every weak spot is used by the young wasp queen in search of suitable building land. In most cases, the wasps cause only further damage here. Exactly when already previous damage, or a negligent construction, allows this.
An invitation seems to be when the facade allows free access to the insulation layer. With their biting tools it is easy for the wasps to nibble on here until a suitable cavity is found. Serious damage occurs when a so-called cold bridge is caused by the feeding damage. The façade itself is therefore not particularly endangered because wasps do not nibble through plaster, concrete, stone or similar hard substances.
Endangered places in the facade are:
  • Cracks in the outer facade
  • missing, damaged base rails, base profiles (closing edges)
  • Insufficient connection of the concrete slabs to the thermal insulation composite system (ETICS)
  • insufficient reinforcing plaster (with fabric) when connecting, masonry and finishing plaster

Shutter boxes

There is almost always an appropriate access to dark, protected cavities that are perfect for a wasp nest. If the construction projects are not discovered soon enough, sooner or later the functionality of these exterior blinds will suffer.


In most cases, wasp nests built in facades or in the roof are only discovered when the population of the wasp state and thus also the nest has increased significantly. Then it's usually mid-August. Now comes the time when the wasps get their appetite for sweets and become increasingly annoying. In the time before they are often not perceived.


For this season, it has practically gone. It is, somehow for the last warm days in the open, to arrange with the wasps. There will no longer be any additional damage to the building structure.
An uninhabited nest can then be easily removed in winter. It is important to then completely eliminate the nest and the environment, for example, with a water-vinegar mixture, finally thoroughly clean. Then, for the young queen in the spring, this place has no incentive to rebuild her nest in this environment. Of course, after that, all structural loopholes should be repaired.
Tip: Better yet, waiting to remove the nest until early spring. Because in winter, the nests are still like beneficial insects, such as the parasitic wasp, used for wintering.


Wasps fly plum

However, when you discover a nest and it becomes a threat to the family, you are faced with the question: How will we get rid of it as soon as possible? Once again, if one discovers a large, finished wasp nest, it will in the same year, the house no longer cause much damage. The only question is: can we live with it until November, or is this impossible? For example, due to:
  • Allergies in the family
  • they have access to the interiors from the roof
  • Incoming route to the nest runs across heavily used paths, entrances
In these cases it is best to turn to a competent specialist counselor in the community. The local fire brigade can either help or give advice.


There are several reasons for not removing wasp nests by hand. Here are the most important ones:
  • you should never radically kill any living thing
  • free-to-sell insecticides against wasps are not potentiated enough for effective use
  • Fumigating is a very dangerous idea, especially in older homes
  • Lock entrances (gluing, filling): very bad in nests at the house, new corridors are bitten through, possibly even into an interior
  • all failed attempts to destroy a wasp nest make the animals doubly aggressive
  • The Federal Nature Conservation Act (BNatSchG) prohibits the killing of wild animals without good reason
In case of an emergency it is always better to consult a specialist. The responsibility can be found out about the fire brigade or the respective community.

Precautions, prevention

The best way to protect the home and residents against structural damage is by prevention.


Wood is a substance that wasps need for their nest building. Badly maintained, rotten wood at the house is an invitation. Meanwhile, there are also environmentally friendly paints and varnishes, with which you can work on wood, so they no longer offer the wasps incentive. A good care of wood paneling, roof trusses and wooden cladding should take place regularly, for the sake of the building fabric alone.


For facades cracks and missing edges are not to be taken lightly.Regular inspections and repairs, if any, keep the house in good condition and make it unattractive for apartment-seeking queens.
Tip: Attention, any free access to the insulation material between the facade and the wall is attractive for wasps in search of a new home.

Shutter boxes


Here you can take preventive care to keep the openings as small as possible and to check more often in the spring. True to the motto, warding off the beginnings. Actually, this is good to watch. With a few lemon juice splashes you can still prevent the queen from settling here. If it is already too late, do not even try to get to the nest or inject with poison. In each community there are contacts who can help with problems with wasp nests.


If a wasp nest poses no threat to the house and its inhabitants, it is best left to them. If one observes a few rules for a peaceful coexistence, there will be no unpleasant incidents.
  • do not get too close to the wasp nest
  • There are wasps nearby, no hectic movements
  • Wasps do not blow
  • Regularly eliminate fallen fruit
  • Take care when eating and drinking outdoors
  • if necessary, install mosquito screens in front of the windows
To protect the wasps, two laws apply:
  • according to § 39 Abs. 1 (...) of the Federal Nature Conservation Act (BNatSchG) it is forbidden to "kill wild animals for no reasonable reason". This law is of course a matter of interpretation, but also offers the quite frequent and annoying Kurzwaswespen a fundamental protection.
  • according to § 44 paragraph 1 (...) of the Federal Nature Conservation Act, it is forbidden to "kill wild animals of specially protected species." In addition to this, species protection is governed by the Bundesartschutzverordnung (BArtSchV). Among the protected wasps are the hornets and three species of long-headed wasps (round wasp, button horn wasp and Saxon wasp). But even the middle wasp is considered worth protecting, although it is not named.
As punishment the law provides for fines of 50,000 euros as well as imprisonment for up to five years. These are also reasons enough never to commit yourself to a wasp nest. To make matters worse, certainly not all long-headed wasps can distinguish from short-headed wasps. Even confusions with bee nests occur again and again.
Tip: House owners with wasp nests are not legally responsible for any damage or nuisance that these ("their") wasps cause to neighbors.
It is the old game, man loves nature as long as he thinks he has it under control. Especially as long as she does not harm him or his property. There is certainly the possibility of a peaceful coexistence with the wasps. Make homeowners, homeowners damage to the house, which are supposedly caused by a wasp nest, it also means to be completely honest: who was there first? The crack in the facade or the wasp nest?

Video Board: Wasps nest in cavity wall of a house..

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