Once termites have gained access to timber, they excavate it internally. To maintain the high level of humidity and temperature necessary, termites leave a thin layer of timber around their activity, concealing their presence.
Earthen Packing: Termites working inside timber may produce large masses of mud-like earthen packing on the surface often seen on foundation walls where they meet flooring or bearers and joists. Workings in buildings associated with several destructive species can be found in a wide range of situations and may or may not be directly part of primary or secondary nests.
Excavation of Wood: Termites excavate wood leaving a thin outside layer of timber intact - the type of excavation varies from flutings to hollowing to large galleries depending upon the species.
Collapsed Timber: Termites excavate the internal structure of timber, leaving a thin shell. This protects them from predatory creatures and desiccation. The surface of heavily damaged timbers will often ripple slightly, providing a useful clue to damage. The type of damage to timber is often characteristic of the species, for example Coptotermes acinaciformis often excavate leaving nothing more than paper-thin parallel sheets, whereas Schedorhinotermes spp. and Nasutitermes spp. create fairly clean excavations, with characteristic plaster-like earthen workings. Depending upon factors such as colony size, location, time of year, and type of timber, termite damage can be considerable within 6 months of their accessing the building.
Termites do not necessarily work through a building in logical sequence - the roof framing may be attacked prior to the rest of the building if the roof framing timber and conditions are more susceptible than other areas. Termites enter walls from foundations and concrete slabs and can destroy structural wall timbers between two levels of a property on their way to warmer roof timbers. This damage may be concealed by the gyprock. Damage may only be evident when walls are opened or there is a collapse or distortion of flooring or internal joinery, which affects the closing of doors and windows. Bearers and joists may also be damaged beneath flooring.
Damage to roofing timbers often follows an infestation in the walls. The top plates, located immediately above the walls, are often severely damaged although this may be concealed by insulation. Unless a roof is inspected every 6 to 12 months, damage to structural timbers can be severe and extensive. Coptotermes acinaciformis will also damage and penetrate material around electrical and telephone cables, a wide range of plastics, cardboard, polystyrene, leather, cotton and almost any material which obstructs its path.
Termite damage may include:
- Earthen masses on architraves of doors, walls, stairs or skirting boards
- Blistering, bulging or staining of paint on windows, door architraves and skirting
- Damp areas on walls may betray the presence of moist earthen material in which termites live
- Electrical failures causing fire by shorting electrical wiring in subfloor areas and roof cavities
- Earthen leads up piers over ant caps or concrete slab edges to enter walls on the way to roof
- Earthen masses in the subfloor area under moist situations such as the bathrooms and kitchens where they act as termite "half-way" properties or in roof cavities and walls
- Damage to flooring bearers and joists of properties with pier and wall construction
- Damaged roof timbers especially top plates because of their location above the wall cavity