Your reader’s concern about the pitfalls of constructing a school around two 120-year-old plane trees (23 November, page 38) mirrors those of the client and design team at the outset of the project four years ago, but a great amount of consideration went into ensuring the continuing health of the trees.
Previously, they were extensively surrounded by tarmac playgrounds. After a specialist health check established that they had more than 60 years of life ahead of them, a range of measures were undertaken to safeguard their continued existence as the centrepiece of the new school.
Solid boarding protection went up outside the perimeter of the tree canopies from the outset, even before demolition of the old school commenced. The trees were also pruned to reduce stress on their root systems during construction. No construction was undertaken under the tree canopies, other than scraping away the existing tarmac and resurfacing. The foundation system selected was mini-piling, which minimised any damage to the root system beyond the tree canopies. Finally, we ensured that no fibrous roots were found in the areas of construction. The final landscaping works have included areas of soft planting in the vicinity of the trees that are more extensive than before.
Major construction activities were completed by autumn 2006. The trees broke into healthy leaf in spring, and received a further check from an aboriculturist, who confirmed that all was well.
The Larmenier and Sacred Heart primary school design team