This impermeable barrier acts as a cut-off wall & effectively prevents tree roots and also moisture movement, thus stabilising the soil, and clay contraction and expansion under the footing. It also act as rhizome barrier and protects your building. For more information, please contact us now. Root Barrier, Unit2, 44 Telford St, Virginia Qld 4014, AU, Ph: 1300 13 66 44, http://rootbarrier.com.au/