Geological data of Australian soils shows that certain areas can be classified as being unsuitable to sustain loading from heavy structures. Structural fractures can occur though ground swell of certain clays or the subsequent settling of reclaimed areas when positive loadings are imposed.
A wide study of these soils has shown many areas in Australia, particularly in the eastern states and South Australia, are unsuitable and recommends that care be taken when designing structures to allow for movement both negative and lateral.
Building foundations cause an increase in the moisture content of underlying clays by the interruption of evaporation.
Without evaporation, capillary water is allowed to rise beneath the building and swell the sub-foundation clays.
BildaVoid Concrete Void Forming Systems have a proven record as a means of providing a void as an economical safeguard against the swelling and contraction of these clays.
Placed under beams and side by side under ground slabs, BildaVoid Concrete Voidforming Systems are left in place to deteriorate through moisture or soil bacteria action. The rate of deterioration is determined by seasonal conditions. It is estimated that the time required for swelling pressures (from a rise in capillary water) to cause damage is generally a minimum of six months or longer.