Termite Damage to Buildings: Nature of Attacks and Preventive Construction Methods

Abstract

Problem statement: Termites are an essential member of the soil ecosystem and are found throughout the world. In their natural environment, they improve soil pH, organic carbon content, water content and porosity by cycling dead organics. However, they can negatively impact human welfare by causing damage to unprotected timber structures, underground cables, earthen dams, irrigation ditches and farming equipment. Globally, the annual economic cost of termite damage and termite prevention is estimated in the billions. However, in underdeveloped countries data on damage is unavailable and it is difficult to estimate the cost of repair as funds are also not available. This study aimed at addressing termite damage in Zambia as a model underdeveloped country by: (a) identifying the injurious species of termites found in the country, (b) reviewing the factors affecting the natural durability of wood, (c) determining the nature of termite damage to timber, (d) determining the most common faulty construction practices which lead to termite entry and infestation in buildings, (e) reviewing chemical and biological techniques for prevention of damage to wood and (f) developing construction methods that will prevent termite entry to buildings. Approach: Several houses in selected villages, towns and cities in different locations in Zambia were chosen for study (ten houses in each location). The injurious species of termites and the natural durability of construction wood were assessed. The damage to timber was evaluated and the faulty construction practices that allowed termite entry to buildings were identified. Results: The interior of each house and the surrounding area were examined for the presence of termites and termite related damage. Termites were found to gain entry to buildings by a number of paths. These included creating bore holes through walls, crawling through cracks in the foundation and climbing through the roof. Conclusions: To prevent termite entry into buildings multiple approaches must be used. Before construction begins all nests and palatable wood must be cleared from the site. Once clearing is completed and before construction begins, wood should be selected based on its natural repellency. If no naturally repellent timber is available wood should be impregnated with a chemical preservative. A chemical barrier must be created by treating all exposed wood in the structure with termiticides and all wood should be placed above a concrete footing. Once materials have been selected additional constructional preventative measures consisting of internal preventive measures within the plinth and external preventive measure in the form of concrete grooves and interlocking apron floors around the periphery building should be put in place. Educational and promotional activities will further lead to prevention of termite attack to buildings.