Bringing down the house

The truth about Japanese knotweed and damage to property

We’ve all heard the rumours about Japanese knotweed growing through concrete and pulling down brick walls, but can a plant really pose such a serious threat to our homes? Here we separate the fact from the fiction and bust a few myths to give you the truth about this thug of the plant world.

  • Japanese knotweed can’t grow directly through concrete. It can certainly exploit cracks in concrete, however, and force its way up through expansion joints in concrete slabs.
  • You’re unlikely to see knotweed sprouting through your living room floor, but it’s not impossible. We’ve seen it growing up behind a skirting board, where a new extension joins an existing house.
  • Japanese knotweed can take down a brick wall. Over time it will grow into the brickwork, destabilising it and ultimately forcing it apart. It can also grow up into the cavity wall of a house, pushing the inner and outer skins of the wall apart. We’ve even seen it breaking out of a chimney pot and flat roof!
  • Knotweed easily grows through asphalt, lifting driveways and breaking footpaths apart.
  • Knotweed’s underground root system and above ground canopy can exert pressure on fences, destabilising them and causing them to collapse.
  • The plant’s powerful underground root and rhizome system can grow into drains and sewers, blocking them and breaking pipework.

The truth is that knotweed does cause significant damage, especially if left uncontrolled, which is costly to repair. That’s why mortgage lenders won’t lend on an affected property unless a professional treatment plan is in place with an insurance-backed guarantee.

If you’re worried about Japanese knotweed growing on or near your property, contact us today for free advice by calling 01932 868 700.

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