PLANNING FOR COMPLEX SITE WITH ENGINEERED FOUNDATIONS & TPO TREES

Date Completed: 14/09/2016

BROCK CHARLES ARCHITECTS

Full planning consent was obtained for two single storey side extensions to a residential property in Kenilworth.

The site featured a large number of mature Lawson cypress subject to a Warwick District Council Tree Preservation Order (TPO). The design proposed the construction of building foundations within the root protection areas (RPAs), requiring a solution that mitigated damage to the roots of several trees.

THE BRIEF

    • Undertake a tree survey following the recommendations of BS5837:2012. Prepare a tree constraints plan with associated root protection areas and tree categorisation for each individual tree, indicating which trees those of significant value and lesser quality

 

    • Project liaison with the design team, architects and planning consultant to discuss the constraints posed and to identify a final design solution in terms of building location, access design and room and window orientation in relation to the trees on site

 

  • Prepare a detailed arboricultural impact assessment and method statement, including a detailed tree protection plan to fully support the clients design solution, and obtain full planning permission for the site

THE SOLUTION

Following the initial constraints survey and preparation of the arboricultural impact plan, a series of investigative trial holes were carefully excavated by hand to assess for the presence or absence of tree roots along the perimeter of the proposed family room extension. This would provide a greater understanding as to the actual root spread of the trees, and the likely conflict with the foundations of the proposed family room extension.

Given the accumulation of roots identified, a traditional trench foundation type was not considered appropriate in this instance.

ENGINEERED FOUNDATIONS

The proposed extension to the northern elevation was proposed to be constructed upon an engineered foundation type. This detailed an engineered design pile, with a surface ground beam to provide an elevated support surface with only a minimal requirement for ground excavation.
The piles could be installed using small precision devises without the requirement for heavy plant machinery. The removal of foundations and built-up ground within the RPAs of retained trees was to be undertaken under the supervision/guidance of the project arboriculturist acting as the Arboricultural Clerk of Works (ACoW).

DECISION

The arboricultural report was assessed by the Warwick District Council Arboriculturist who determined that the statement addressed all previous concern raised, and was considered acceptable. The decision notice was conditioned to be carried out wholly in accordance with the tree protection measures detailed in our method statement.

We will be acting as the project arboriculturist throughout the construction of the approved scheme, in order to fully comply with the tree related planning conditions.