Our Foundation Depth Calculator is designed to enable the user to easily determine the exact foundation depth required when building near trees. The depth of foundation is determined by inputting:
⚫ Plasticity index of soil
⚫ Water demand of the tree
⚫ Mature height of the tree
⚫ Distance of relevant tree to nearest part of foundations and distances elsewhere if stepping foundations
⚫ Allowance for climatic conditions
The Foundation Depth Calculator includes the vast majority of trees found in the UK, however it does not include every single tree. If a tree is not listed you should consult a structural engineer and an arbor culturist for advice.
You can refer to the Technical Manual for more details on foundation depth.