Japanese knotweed is unlikely to cause significant structural damage to buildings indirectly by subsidence, or by collapse, as in a tree-fall. Japanese knotweed does however cause damage, both by its above ground canopy exerting pressure on adjacent walls/fences, but also by its expanding network of underground rhizomes and roots, and, for mature stands, its crown. Read more about the impact of knotweed on property in MD Nic Seal's blog.