[2025] UKUT 053 (LC)

The results of the site investigations confirm that the cause of subsidence is root-induced clay shrinkage. The clay is plastic and thus will shrink and swell with changes in moisture content. Roots have extracted moisture content below the depth of the footings, thus causing differential foundation movement to occur. This is supported by the following investigation results:

- The foundations are at a depth of 900mm which is below the level that normal seasonal movement would occur.

- The moisture content profile indicates a reduction in moisture content between a depth of 0.9m and 2.5m which is indicative of desiccation at this level. This is also coincident with the depth of root activity.

- Atterberg limit testing indicates that the soil has a very high plasticity and hence will shrink and swell with changes in moisture content.

- Suction tests indicate severe to very severe desiccationbetween a depth of 1.5m and 6.0m coincident with the depth of root activity.

- Roots were found to a depth of 2.0m and were identified as either Quercus or Castanea. Quercus are oaks and Castanea include sweet chestnut. In this instance, we consider that the roots will emanate from the large oak beyond the rear boundary. The roots recovered were juvenile and therefore starch was not present.

RECOMMENDATION

The cause of movement needs to be dealt with first. From the results of the site investigation, we are satisfied that the Oak tree within the golf club land can be removed. Based on our analysis, we are satisfied there is no adverse heave risk to the property. Our Mitigation Unit will liaise with the third party in this respect.

Following completion of the tree management works, we will undertake a suitable period of monitoring to confirm stability has been achieved before undertaking repairs to the property.”