Housing developments on sites with mature trees carry specific planning conditions around tree protection. Root Protection Areas, defined by British Standard BS 5837, extend well beyond the visible drip line of the tree and constrain what can be done in the vicinity without harming the tree’s long-term health. Getting this wrong on a housing scheme produces enforcement action from the local planning authority, replacement planting obligations, and reputational cost that no developer wants.
The BS 5837 framework is well established. Every tree of significance on a development site is classified, its Root Protection Area is calculated, and the RPA is protected during construction. Protection typically involves rigid fencing, no-dig zones for surface treatments, restricted excavation methods, and specific procedures where any works do have to occur within the RPA.
For groundworks contractors, the practical constraint is that the RPA often intersects with the work that has to be done. Roads pass under trees. Drainage runs cross RPAs. Foundations approach RPAs at the edges of the scheme. Each intersection requires a specific arrangement that respects the tree protection requirement while still allowing the work to proceed.
The three most common arrangements are hand-dig excavation within the RPA (slow but low root damage), no-dig construction techniques for surface installations (permeable membranes and lightweight aggregate), and route diversions that keep the works entirely outside the RPA (more expensive but simplest). The right choice depends on the specific tree, the works involved, and the planning consent conditions.
GCE’s engagement with developer clients on tree-sensitive sites includes tree protection at pre-construction stage. The arboricultural strategy submitted with the planning application is reviewed against the proposed groundworks programme. Where conflicts exist, they are addressed in advance rather than negotiated on site.
The Local Planning Authority Tree Officer is the key regulatory relationship on tree-sensitive schemes. Their inspection regime typically includes site visits during groundworks, checks on the fencing arrangements, and reviews of any works undertaken within RPAs. Where the works have not been managed correctly, they have the authority to require replacement planting or, in serious cases, to seek prosecution.
For developers, the reputational cost of tree damage on a housing scheme extends beyond the enforcement action itself. Local residents, local media, and local politicians take notice. Schemes that gain reputations for tree damage carry ongoing difficulties with subsequent planning applications in the same area. Prevention is meaningfully cheaper than mitigation.
There is a specific case around root barriers that is worth flagging. Where planning conditions require the installation of root barriers between the built development and the retained trees, the barrier has to be installed to a specific depth, positioned correctly relative to the tree, and made of materials suitable for long-term burial. Cheap or short-cut root barriers fail in service, allowing tree roots to eventually damage the built development. The failure typically manifests many years after handover.
GCE’s approach to root barrier installation on tree-sensitive sites uses specified materials to the depth and location required by the arboricultural strategy. The installation is documented as part of the handover pack so that any future maintenance or investigation has an evidence trail to work from.
For QSs pricing groundworks on tree-heavy schemes, the practical advice is to specify the tree protection scope explicitly in the tender documents. Where the scope is generic, the tender price is generic, and the on-site delivery is variable. Where the scope is specific, the contractors who take tree protection seriously produce different tenders to those who do not. Selection on that basis produces better on-site outcomes.
Talk to Globe Civil Engineering To discuss tree root protection during your groundworks programme on your scheme, contact Globe Civil Engineering on 01223 890727 or email enquiries@theglobegroup.co.uk.
