How do we design structures to manage the risks of termite attack?

Every building should be designed to reduce the chances of problems with all the local pests, not just pest termites. Here’s a basic scheme:

Much can be done to reduce the pest pressure and maintenance costs by including a few simple design features. While my main interest is the exclusion of subterranean termites, design should take account of all likely pests. The following guidelines are intended for architects, designers and managers of large facilities (schools, nursing homes, hospitals, offices etc.) but may be adapted to any construction.
Most pests will take advantage of concealed entry paths. Accordingly, the perimeter of a building should be designed and constructed so that:
  1. Pests are discouraged from gaining easy entrance.
    1. Door should fit snugly with weather stripping and sweeps that close tightly.
    2. All opening windows shall have metal screens which are fixed taught and seal to the frame with a gasket.
    3. All metal window and door frames shall have joints sealed with a suitable elastomeric sealant.
    4. Cracks, crevices, holes and thermal gaps shall be suitable sealed with a caulk or compressible foam product.
    5. Large holes such as for added or removed pipe openings shall be sealed. Stainless steel wool (pot scrubbers) covered with a mortar or grout is usually sufficient.
    6. Exterior lighting for doors must be far enough away that flying pests attracted to the lights can gain casual entry. Entrance ways should use reflected rather than direct light and light sources should be at the orange end of the spectrum so as to reduce attraction to nigh-flying insects.
    7. Entrance ways, alcoves and attached plant should be designed so as to minimise wind-blown debris accumulation.
All pests need somewhere to live and somewhere to rest.
  1. Pests should not find easy hiding places inside.
    1. Interior wall joints, gaps in panels, window frames, gaps around cupboards and electrical fixtures shall be filled or sealed.
    2. Skirting boards, and floor coverings shall provide no open cavities.
    3. Skirting boards and sheet floor coverings shall be designed and placed so as to be readily cleaned with electrical rotating brush devices. There should not be internal 90 degree corners, rather corners should be radiused to match cleaning capability.
    4. All supply pipes, cables and conduits to be sealed where they pass through walls and panels and, all conduits and ducts to be sealed or meshed to prevent pest entry.
    5. In kitchen, bathrooms and other wet areas, cabinets, sinks, toilets and counter tops which meet walls shall be sealed against water entry so as to prevent pest harbourage.
    6. Air vents/inlets shall be screened with metal mesh of 1 mm aperture size (small enough to block termites) which is fabricated and installed so as to be readily removable for cleaning.
    7. Floor drains require removable coarse mesh screens or similar devices to prevent cockroach passage.
    8. In kitchen, bathrooms and other wet areas, floor-mounted fixtures should, as far as practicable, be either on raised legs (100 mm high) set as to provide easy access for cleaning and inspection or shall be provided with sufficient space for easy access and cleaning ( e.g. toilet cubicles).
    9. In kitchen, bathrooms and other wet areas, drains shall not be concealed under equipment or fixtures.
    10. Storage areas should be designed to permit both inspection and drying air flows. Storage units should be mounted at least 100 mm off the floor. Racks, cupboards or compactus units for long-term storage shall mounted be at least 600 mm from walls. 
  2. Pests should not find easy resting places outside.
    1. Ledges and fixtures should not provide roosting places for birds as faecal accumulations pose a health hazard.
    2. Plant and equipment whether at the perimeter or roof-mounted, should be designed to exclude rodents and bids and to be readily inspected.
    3. Roof should be designed to shed booth water and litter.

All pests need a suitable environment in which to live. A building’s immediate surrounds should not be particularly amenable to the pests’ needs.
  1. Exterior landscaping can create ideal pest environments.
    1. Gardens must not be adjacent to exterior walls such that, at any time, plants will be in direct contact. Plants provide bridges for pests.
    2. Paving at least 600 mm wide should surround the building. In low-traffic areas, paving can be replaced by compacted gravel. Paving is less hospitable than garden beds.
    3. Plants, including grasses, should not encroach on perimeter paving.
    4. No tree,shrub or plant that is known to have extensive or invasive roots (e.g. Bamboo) shall be planted within 3 metres of the exterior walls. Where such plantings are identified, foundations and perimeter paving shall be protected with a root barrier system.
    5. Trees, shrubs and other large ornamental plants shall be spaced to have a free-air gap of at least 600 mm between them at maturity (or to be trimmed to maintain such gaps). Air gaps are important to reduce humidity at the exterior of the building.
    6. Soil levels, paving, features and garden beds shall not interrupt the fall so that rain and other water drains well away (at least 2 m) from the base of perimeter walls.
    7. Garbage and recycling containers for litter shall be mounted on concrete pads which extend not less that 150 mm from the container. Containers shall be mounted not less that 400 mm from walls and shall be positioned on legs to provide at least 100 mm clearance from the pad. Containers shall have self-closing lids.Termites in particular can be encouraged by having concealed access points to the building fabric and by having water and potential food in close proximity.
  2. Buildings should be intrinsically termite resistant.
    1. Physical termite barriers that do not rely on any toxin should be used wherever possible as these generally provide the longest service life.
    2. Footings, retaining walls and any section of wall that might be concealed by soil of accumulations from garden beds etc. should be solid rather than hollow and should have all joints and expansion gaps fitted with a suitable termite barrier.
    3. Moisture and water must not be allowed to accumulate either under the building or against exterior walls. Service life is extended where the perimeter and footing earth stays close to uniform moisture content. Pests problems are reduced where this moisture content remains low.
    4. The roof should be pitched and drain to the exterior. Valleys should be steep to rapidly shed water and litter. Flat roof designs that permit either water ponding or wind-blown litter and bird wastes to accumulate are to be avoided. Subterranean termites will attack a building from the top where there is permanent moisture.
    5. Timbers in soil contact shall be kept to an absolute minimum and where required only known naturally resistant or suitably preserved timbers should be used. Landscaping timbers decay to become major harbourages for pests. Preserved timbers weather and degrade over time and may provide cover for pests. Where preservative penetration is insufficient, pests may be concealed within apparently preserved timbers.


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