Trees are an important environmental asset, however the council recognises that in some instances they may contribute to the subsidence of a building.

Where an application is made to fell a protected tree (one subject to a Tree Preservation Order (TPO) or located in a Conservation Area), due to concerns about alleged subsidence, it is important that adequate information is included to demonstrate that:

• the subsidence has actually taken place
• investigation has been undertaken to show the effect of the tree
• reasonable alternatives to felling have been considered

Application documents where subsidence is alleged

The following information should be included:

• engineers report on assessment of damage to building
• plan and profile of foundations
• full details of all areas of damage attributed to the subsidence including location plan of building in relation to trees both on and adjacent to the property
• soil analysis – including proof of desiccation, details of liquid and plastic limits taken from both a trial pit and control pit
• tree root identification & analysis  from beneath foundation level
• monitoring results preferably for 6 months or more, including level monitoring
• details of any drainage report carried out for the property
• details of previous underpinning or relevant building works to the property
• the range of alternatives considered and estimated costs, including a comparison between scenarios in which the tree is retained or felled)

In some cases officers may ask for further information such as:

• details of vegetation in the vicinity and its management since discovery of the damage
• a plan showing the vegetation and affected building
• the location and identification of roots found - where identification is inconclusive, DNA testing should be carried out

For private individuals who have concerns regarding alleged subsidence and TPO trees please contact the Arboriculture Team on 023 9244 6485, or email treeofficer@havant.gov.uk.