Protecting a building from ground emanating gases or attack by agents such as fungi or termites

摘要

A system comprises a gas impermeable barrier (10) providing a void between gas containing and adjacent regions and a pump (23 Figure 2) for pumping gas into the void to create a pressure differential between the void and the gas containing region, furthermore, first and second valve means (29 Figure 2) are in communication with the void so that, should the void pressure fall below a minimum value, possibly due to pump problems, the valves open allowing air currents to naturally ventilate the void. The barrier may further include a layer of cast material (50, Figure 6) on the side facing the adjacent region, having a number of hollow projections (13) defining a number of cavities, such that the cavities contain cast material and are integral with the cast layer. In another invention a system includes a void formed between a building and an adjacent region, ventilation ducting (24, 27, 28, Figure 2) communicating between the void and the atmosphere, means for closing the ducts and a means introducing treatment material into the void.