Durability of Building Materials and Components in the Agricultural Environment: Part I, The agricultural environment and timber structures

Agricultural environments can be very aggressive to building materials and components due to the specific physical and chemical agents present. It is therefore evident from several viewpoints that the consideration of the durability of building materials and components is an important aspect of design. Economic considerations, animal welfare, pollution control and environmental aesthetics are all linked with durable design. In this review, an overview of the existing knowledge on durability of different building materials and components subject to this specific environment is given. The first part of the review focuses on the characteristics of the agricultural environment and the durability of timber structures. Different farm buildings are examined, including animal houses for cattle, pigs and poultry; slurry pits; horticultural buildings; farm roads; and silos and other storage systems for agricultural products. The susceptibility to degradation of these buildings or their components is highlighted. The use of wood in agricultural structures, its deterioration and methods for protection are dealt with. The review reveals that little has been published about timber degradation in specific agricultural environments. Laboratory tests and field trials are mostly developed to simulate decay in timber either in contact with the ground or in above-ground structures. Recent research focuses on fungal decay and attack by insects and (seldom) bacteria on different types of wood under a variety of environmental conditions (temperature, humidity, etc.). Methods to distinguish between fungi are proposed. Different measures to quantify the degree of decay are investigated. New diagnostic methods for detecting incipient wood decay in vitro and in situ are developed. New wood preservatives are being proposed continuously, including different methods to retard the leaching of boron from treated timber and the use of monomers that are polymerized in situ. Continuously, more attention is paid to the design of environmentally benign methods for preserving wood in service.