Here are some simple tips to help reduce the risk of attack by subterranean termites as well as improving the ease of inspection around your property.
All areas of the subfloor and/or external perimeter of a structure should be kept clear of stored items. Any items stored within the property’s boundaries, especially those containing cellulose such as timber, cardboard, paper, etc must be stored in a manner that allows clear access for inspection and does not bridge, breach or disturb any part of an installed subterranean termite management system. You need to make sure that any items stored in subfloor areas do not provide accessible food for termites, hidden paths for termite entry, or reduce effective ventilation.
Timber off cuts, form timbers, etc, existing in subfloor and perimeter areas of a structure provide an attractive food source and nesting site for subterranean termites and pose an unnecessary risk. You need to remedy this as soon as possible by removing these items from subfloor and external areas.
Substandard ventilation in the subfloor areas of a structure result in high humidity and a moisture rich environment. Wood decay fungi and subterranean termites thrive in these conditions. Strong airflow by natural or artificial means may aid in reducing temperature and humidity in the subfloor area resulting in evaporation of soil moisture. Cross-flow ventilation with the avoidance of eddy or still points should be optimised.
Moisture sources can result in unnecessary moisture accumulation which is one of the main contributing factors in subterranean termites nesting close to, or within structures, particularly in drier areas. You need to manage moisture sources to reduce their effect on structures. Surface and ground water should be diverted away from the structure by installing appropriate drainage systems. Look out for:
- roof drainage e.g. leaking plumbing, inadequate down-pipes;
- surface drainage e.g. ground sloping towards walls, raised ground levels, garden beds and wind-blown soil;
- plumbing e.g. leaking showers, unsealed tap flanges, leaking taps, cracked and perforated pipes, blocked drains and faulty connections, inadequate air conditioner and/or hotwater system drainage, flashing around windows and doors, and leaking garden/lawn irrigation systems.
Vegetation & Gardens
General vegetation around foundation areas should be managed so that inspection zones and airflow are not impeded. Planting of trees near buildings must be avoided to limit root intrusion. Climbing plants and/or thick vegetation growing against the side of the structure will bridge or breach the subterranean termite management systems and provide subterranean termites with a well concealed entry point. You need to remedy these situations as soon as possible by clearing plants away from the structure, leaving a clearance of at least 300mm and/or installing root barriers 300mm out from the foundation.
Garden beds with coverings such as pine bark, wood-chip and/or materials containing cellulose create an environment conducive to subterranean termite activity, in addition to creating a bridge across any subterranean termite management systems that are installed. At the very least these garden coverings must be kept at least 300mm from the base of the external walls or any building element in contact with the main structure. Garden beds must not be placed, nor shrubs planted against the perimeter of the building.
Vegetation must be maintained so that it does not obstruct the weep holes and/or ventilation. Soil levels must be maintained at least 75mm below weep holes. Any disturbance to soil adjacent to building where a termiticide treatment is installed must be repaired immediately.
Structures such as fences, retaining walls, pergolas, etc should be constructed using termite-resistant components. Attachments to buildings such as down-pipes, service pipes, attached fence posts, air conditioning units, hot water systems, rainwater tanks etc must have a nominal gap of 50mm minimum at the ground contact point to allow clear and uninterrupted visual inspection. All timber posts, fence palings, house battens, etc in ground contact must have a nominal gap of 50mm minimum to allow clear and uninterrupted visual inspection, or have an effective termite management system installed where practical.
Disturbance to treated soil areas
If your property has had a termiticide soil treatment installed, the disturbance, adding to and/or removal of this soil will result in a break to the treated area allowing subterranean termites entry through the breach. Disturbance may be caused by tilling of soil, pets and/or children excavating soil, degradation and erosion by way of water run off, installing paving and/or concrete paths, etc. Any suspected breach to the treated area must be investigated immediately so that rectification to the breach can be undertaken.
Where the finished level of paths, pavers, soil, garden beds, etc are built up above flooring, subfloor level or wall vents, an environment conducive to subterranean termite entry is created. It is important that you consider environmental rectification, the installation of an effective termite management system where practical and/or an increased inspection frequency to these areas.
Dead Trees and Stumps
Dead trees and/or stumps are favoured nesting sites for subterranean termites, and must be removed as they pose an unnecessary risk to the structure. Treatment may be conducted to these areas and is highly recommended prior to removal, if subterranean termite activity is located. However this treatment offers no protection from future subterranean termite activity.
Where new building or alteration, landscaping, drainage works to a new or existing buildings is to be contemplated, you should seek advice from an accredited timber pest technician well in advance, to ensure that any components of your management plan are not compromised, and to ensure that appropriate management measures are implemented.