January 24, 2019


Thorteck Ltd Install screw piles as they are the foundation solution of choice for projects in tree root protection zones:

  • Small diameter piles require augering a hole from 100 – 250mm diameter to the required depth, before removing the soil and sections of tree roots from the excavation to allow the pile to be seated.
  • Screw piles are a far less invasive foundation system as they consist of a slender pile shaft with a maximum diameter of 89mm and a number of thin helices 350mm max diameter.
  • This  slim pile shaft may damage a very small portion of the root system upon installation, with the helices also causing minimal damage but the helices are fairly blunt so we assume would act to move the roots out of the way rather than cut through them unlike driven piles .
  •  It could be argued that the installation process provides some aeration to the soil round the roots which may well actually be beneficial to the tree.
  • Screw piles support load directly on the aforementioned helices which are placed well below the root ball of the trees in line with the Arboriculturalist’s recommendations, this ensures that soil and tree roots within the root ball do not experience a loading influence so remain entirely undisturbed following installation.
  • Screw piles are resistant to water movement in the soil for example; heave or shrinkage experienced as a result of water uptake from the soil by the tree.
  • Each pile is installed to a specified torque during the installation process so no pile testing is required once in the ground, putting the tree at further risk of damage.


Screw piles are favoured by various County Councils as the foundation system of choice in root protection zones, and we have had positive recommendations from senior Arboriculturists in the industry with respect to the minimal impact of screw piles used near trees

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