Tree Solutions Permavoid Sandwich Construction (SC)

A single layer of 150mm deep Permavoid^® units is laid in a raft arrangement over the potential root zone of the tree. These units are filled with a suitable nutrient rich soil/sand mix and then encapsulated with geotextile (generally Permatex 300 but if there is potential for hydrocarbon contamination then this may be substituted by Permafilter^® geotextile). The soil infill will settle within the Permavoid^® units leaving an air filled void.

The features and benefits of this construction are as follows:

• The Permavoid^® raft will act as a protection to the tree roots. This will promote a uniform directional growth of the roots, thus stabilising the tree.
• The high strength Permavoid^® Units will dissipate vertical and dynamic loadings to protect the soil around the tree roots from compression and compaction due to trafficking.
• The Permavoid^® unit is filled with nutrient rich soil, acting as a container and retaining moisture and nutrients which are released to the tree roots over time.
• The soil within the Permavoid^® will settle creating an air layer within the structure. This provides aeration and prevents root growth through the surface, thus protecting expensive surfacing from damage caused by root heave. Employing the Permavoid^® Tree Protection System in this manner closely replicates conditions found on the forest floor by providing a layer rich in nutrients above the underlying tree soil.

Ancillary Items

• Permavoid 150
• Permaties
• Permatex 300 Geotextile
• Permafilter Geotextile
• Permavoid Tree Soils