Timber is a common material in the construction of buildings in many tropical countries. However, exposure of timber to conditions of high moisture can lead to problems of fungal decay or distortion. Care in the design of structures will reduce the significance of moisture-related problems and improve the performance of timber under tropical conditions. If timbers cannot be protected from dampness by design, it will be necessary to apply preservative or to select naturally durable timber species and exclude sapwood, to provide adequate service life. Insect attack, particularly by termites, can cause serious deterioration in service. Appropriate preventive measures include the selection of timber of high natural durability and the use of preservative chemicals.