Sandwich TreeRaft System

The Sandwich TreeRaft System provides a pressure spreading systems that spreads the load of vehicle movements around the rooting area of the tree and eliminate/reduce soil compaction within the pit. The sandwich construction replaces the foundation layer, creates a thinner base course and increases the available root growth volume. The open structure produces an open air layer beneath the pavement and prevents root damage to the pavement. Sandwich constructions are specially developed for situations where compaction of root space is to be expected due to traffic loads.

Vehicular and pedestrian traffic over unprotected areas within the tree root zones of trees can cause compaction of sub soils which leads to reduced voids within the soil structure. This reduces air and water transfer to the roots themselves which can ultimately lead to the root structure declining and the eventual loss of the tree. Because of the compaction the roots will search for air and water just underneath or between the pavement or asphalt.

A sandwich construction is placed on a layer of tree soil, or structural soil, beneath the surface of the pavement. The system can be used in areas with existing or newly planted trees. The Sandwich Tree Raft System pressure spreading system is also a good alternative in areas where it is not possible to use other subsurface structures or in areas with a high groundwater level.

We advise that the system should not be used within the zone of rapid taper (distance depends on the tree species, but to be sure ask a tree specialist when working within a 2 metre circle around the tree). To prevent the sandwich construction from lifting we recommend that you use our Tree Root Directing panels. Please remember that the situation could differ and depends on your expectations and objectives. Our experts at Green-tech Specifier will gladly help you find the best solution.