MJ Abbott

Construction of access road through tree protection area

The Meath Epilepsy Trust, Godalming, Surrey

Project summary

Careful construction in a tree protection area

This project comprised the construction of a new access road for a proposed extension to the existing Meath Epilepsy Centre in Godalming, Surrey. The access was not only for future use by staff and residents, but also for construction traffic to access the site of the proposed extension to the building.

The proposed route was through a very sensitive tree protection area, so specialist materials, processes and methods were required to ensure the trees were not damaged as a result of the works on site. Due to planning conditions and the extremely sensitive nature of the area, the proposed road had to be finished in grass and could not be excavated through the tree root protection area which formed the majority of the route.

The works were overseen by Pete Davies of consultants PJC Consultancy, who devised the arboricultural methodology for the works and carried out regular site visits and inspections to ensure full compliance with his recommendations.

Geotextile and geomembrane specialists Geosynthetics Ltd were brought in to propose the formation profiles and materials for use through the specific no-dig tree root protection areas.

The whole site was fenced off to prevent damage to the surrounding trees and a number of limbs, tree canopies and small low quality trees were removed to enable to works to proceed on site.

The works commenced with the careful removal of the existing surface vegetation prior to the placement of a TreeTex pollution control geotextile to the formation of the access road.

Timber edging was then installed to define the route of the proposed access road, ensuring that no vehicles travelled through the root protection area, meaning all materials had to enter the site at the start of the access road and could only be transported on the fully completed sub base formation.

150mm deep Cellweb was then pulled out, pinned and stapled to the route of the access road prior to being in-filled with organic Type 3 sub-base material. This organic base will allow for the proposed finished surface of Golpla tiles to be laid directly onto a thin blinding layer of the sub-base and reduce the depth of the build-up, which in no-dig areas is critical to ensure that the road can tie into surrounding features.

The finished surface was then overfilled with Type 3 to protect the surface of the Cellweb during the extension construction works.

Once the extension was completed in early 2015, MJ Abbott returned to site to excavate the overfilled surface, prior to blinding with a thin layer of sharp sand, laying Golpla grass pavers, infilling with sand/soil rootzone, and seeding on completion.