Subsidence is one of them words no one wants to hear from a building surveyor, but if you find your property does have subsidence, the general first thing to look for is drainage in the area of damage to the property. We get calls from building surveyors asking for detailed CCTV subsidence surveys on the drainage system. These differ slightly from a normal cctv survey or even our full home buyer pre purchase survey. They include surveying all the accessible drainage like the home buyer drain survey but also on request we break into the rain water system to check the drain runs to the soak-aways. We also check the drainage within five metres of the cracking to the property with a water test on any drainage. This is to check if the drainage is leaking into the foundations of the area of damage. Quite often we find cracks, roots or breaks to the pipe work on subsidence surveys, which in turn means a very large amount of water is running under the property and washing away soil creating easy movement for the building. Sometimes this is down to poor installation but on most occasions the older properties the cause is minor ground movement. Once the surveyor receives the report they generally approve repairs to the drainage system prior to any work being carried out to the damage on the property.