Chemical-Free Eradication of Longhorn, Deathwatch and Anobic Beetles in Buildings

Thermo Lignum Gebäudebehandlung
Thermo Lignum Treatment of a Building at the Freilichtmuseum at Detmold in Germany and at St. John's Church, Oxborough, England


For the treatment of insect-infested structural or architectural timbers, our WARMAIR process has been adapted for use with portable gas fired heating equipment. It is a critical function of the WARMAIR building treatment to prevent damage to any of the structural elements through moisture loss by controlling the relative humidity (RH) of the atmosphere surrounding them during the heating cycle.

Property Survey

Initially a survey must be carried out to assess the extent of the infestation and determine the feasibility of the treatment with regard to access, insulation, air- distribution, volume of the structure and available site services. An inspection report will then be submitted together with a quotation for the cost of treatment

Damage to structural oak timbers caused by Death watch beetle

The Longhorn Beetle larva is a significant destroyer of coniferous timbers. They infest roof trusses, beams, parquet and floorboards in general. The adult beetle leaves large oval shaped exit holes.

Anobium punctatum, the Common Furniture Beetle, prefers a cool climate and damp wood, and The Deathwatch beetle has a preference for very damp and rot infested oak. 

Focussing on the ‘KILL’ temperature

All of the life-cycle stages of the wood-boring insects that we target, will die when exposed to 55/56oC for an hour. In order to achieve this temperature at the core of a large timber beam we have to slowly increase the heat input, whilst controlling the RH, over many hours.

Unlike many thermal building treatments, and in the interests of the building fabric, we limit the air input temperatures to around 75°C instead of up to 120°C, to meet the requirements of responsible conservators and restorers. 

Site Operation

Prior to enclosing the structure or component with insulating materials, up to 50 temperature and humidity sensors are positioned at predetermined locations within the treatment area. Up to 10 temperature probes will then be inserted into 4mm holes drilled into the largest cross-section beams in order to measure the heat at the core of the timbers.

The Thermo Lignum process is then applied by passing warm humidified air into the enclosure via insulated flexible hoses. A continuous flow of data is received via remote  control from the sensors, enabling the operator to accurately monitor and adjust accordingly, the RH and temperature within the enclosed atmosphere

Site requirements

Designed to deliver our acclaimed service to site, the fast and effective system requires just 3-phase electrical power (mains or portable generator), mains water supply and level standing to become operational.

It is important that positioning of the heaters and ancillary equipment is achieved as close as possible to the structure. By optimising the distance between the heaters and the treatment area gas consumption can be reduced.

Portable, Prpane Gas-fired Heating Equipment.
Portable, propane gas-fired heating equipment
Live larval samples are used to prove insect mortality.
Live larval samples are used to prove insect mortality
WARMAIR Hose in the Roof of Aachen Dome.
WARMAIR hose in the roof of Aachen Dome

Insect Pests can damage any organic materials in buildings.

Our WARMAIR® treatment will kill the lot!

Rothschild Hunting Lodge, Niederösterreich
Rothschild Hunting Lodge, Niederösterreich

We treat individual rooms, whole cathedral trusses and entire buildings.

Treatment of a medieval wooden Ceiling at St. John’s Church, Oxborough, England


The ‘Angel’ carvings (right) were removed from the structure and treated in our static chamber in London

Treatment of woodworm
Treatment of ‘woodworm‘ and dry rot infestation in the dome at Aachen Cathedral, Germany