Professional methods (fumigation, hot air, microwaves)

Some infestations are beyond the scope of what can be done by DIY methods – in such cases, pest control professionals are needed. Professional control methods are mainly used for very severe or hard-to-reach infestations, such as in the rafters of an entire roof structure. A common method is fumigation: the building or affected components are hermetically sealed and flooded with a special gas (e.g., sulfuryl difluoride) that kills all wood pests.

Advantage: Fumigation reaches even the last larva deep in the wood – the infestation is completely eliminated in one go.

Disadvantage: The process is very complex and costly, and all people, food, and pets must be removed from the house during treatment. Fumigation may only be carried out by certified specialist companies.

Another option is the hot air method: large hot air blowers are used to heat a roof truss or entire room to over 55°C and maintain the temperature for hours until all pests are killed. Microwave devices work in a similar way, with specialists selectively irradiating infested wooden beams to heat the larvae inside. These technical methods are just as effective as fumigation, but are somewhat gentler on materials and more environmentally friendly (no gas). However, they require expensive special equipment.

When should you call in a professional? Experts advise: Professional help is required at the latest when load-bearing wooden parts (roof beams, ceiling beams, etc.) are affected. On the one hand, because laypeople often cannot reach all cavities and the structural integrity may be compromised. On the other hand, because beams that have been weakened may need to be replaced or reinforced after successful treatment. In the case of valuable antiques, it is also worth consulting a restorer or pest control expert to have the furniture gently treated (e.g., in special climate chambers) to remove woodworm—improper DIY attempts could reduce the value of the piece.

Conclusion on professional methods:
Professional methods guarantee complete elimination of the infestation, but are only the method of choice in severe cases. They are expensive and time-consuming, but sometimes the only option (e.g., for house longhorn beetles in the roof structure). A combination is often recommended: The expert first removes the infested dead wood, renovates the structure, and treats the remaining wood with a wood preservative (insecticide) for safety. This way, you are on the safe side.

Sources:

https://www.haus.de/leben/holzwurm-bekaempfen-diese-hausmittel-helfen-24241

https://www.immobilien-und-hausbau.de/rund-ums-haus/heimwerken/holzwurmer-bekaempfen/#:~:text=Gas

https://www.selbst.de/holzwurm-holzwuermer-erkennen-und-bekaempfen-45690.html#holzwurm-bekampfen-was-tun