This guide explains in easy terms why properties founded on clay soils suffer from cracking and provides practical, step-by-step advice and guidance to the home owner on what action, if any, should be taken when confronted by subsidence. It answers key questions, such as why properties founded on clay soils suffer subsidence and heave damage how cracks caused by foundation movements can be distinguished from damage due to other causes how to reduce the risk of damage or prevent existing damage from worsening what investigation is needed and how its is decided whether or not underpin.