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A Balanced View. Very little root action leading to subsidence damage to buildings in the UK is caused by direct physical pressure exerted by roots. A tree has to be very close to the structure indeed for such damage to occur. Planting a tree so close to a structure that trunk buttressing or increase in trunk diameter was being restricted could lead to damage. More commonly, pavements and boundary walls with little or no foundation may be lifted by large shallow roots of, for example, Populus, poplar, species. Buildings with adequate foundations, standing some distance from trees, are very rarely subject to such direct damage.

Most reported damage is secondary in nature. The problem is confined largely to soil types that shrink considerably on drying. In the UK these are mainly certain types of clay and some peaty, fen soils. Under conditions of drought when tree roots remove water from shrinkable soils, they accelerate the drying and shrinking process. This can lead to loss of support to inadequate foundations and subsequent subsidence. Continued drought, even in the absence of trees, can lead to subsidence in such circumstances.

Tree root spread data have most relevance to relatively ‘safe’ planting distances when relating to trees growing on shrinkable clay soils. Planting distances on other soil types that do not contract on drying have to be determined more by consideration of the respective scale of the buildings and trees, the ultimate size of the trees, and the desirable or undesirable qualities of the trees concerned. In all cases it is wise to consult a qualified expert.




    Suggested minimum
distance from
Maximum root
spread recorded

Cypress Cupressus 3.5 metres 20.0 metres
Cypress Chamaecyparis 3.5 metres 20.0 metres
Birch Betula 4.0 metres 10.0 metres
Apple Malus 5.0 metres 10.0 metres
Pear Pyrus 5.0 metres 10.0 metres
Cherry, Plum and Peach Prunus 6.0 metres 11.0 metres
Hawthorn Crataegus   7.0 metres 11.5 metres
Rowan & Mountain Ash Sorbus 7.0 metres 11.0 metres
Plane Platanus 7.5 metres 15.0 metres
Lime Tilia 8.0 metres 20.0 metres
Black-Locust Robinia 8.5 metres 12.4 metres
Beech Fagus 9.0 metres 15.0 metres
Ash Fraxinus 10.0 metres    21.0 metres
Horse Chestnut   Aesculus 10.0 metres    23.0 metres
Elm Ulmus 12.0 metres    25.0 metres
Maple & Sycamore    Acer 12.0 metres    20.0 metres
Oak Quercus 18.0 metres 30.0 metres
Willow      Salix 18.0 metres 40.0 metres
Poplar Populus 20.0 metres 30.0 metres

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