Wood in the Trees

Hawkins\Brown completes an engineered timber pool pavilion at Freemen’s School

Photos
Jack Hobhouse

Set among trees in the grounds of City of London Freemen’s School, an independent boarding school in Surrey, a new indoor swimming pool designed by Hawkins\Brown is constructed from engineered timber to establish a connection to its context and minimise embodied energy.

Comprising a 25-metre, six-lane competition pool, with changing facilities and a multi-purpose teaching and events space, the complex replaces a pool building destroyed by fire in 2014, though on an alternative site next to existing sports facilities.

Its construction incorporates a glue-laminated timber portal frame, braced with cross-laminated timber panels, which provide both structure and internal finish and allow fast, efficient assembly on site. (The erection of the glulam frame and CLT walls and roof took just over three weeks, allowing the fully finished building to be delivered in one year). The use of timber also offered specific advantages in dealing with the challenges of a pool environment, says the architect: it is resilient, a thermal insulator and corrosion resistant.

To minimise the impact of the building on the grad-II*-listed landscape, the lower-ground floor is partially sunken. “This moulds the structure into the surrounding scenery and preserves a large number of the existing trees”, says the architect. The entrance is identified by the highest point of the gently pitched roof. Internally, “the structurally expressive roof geometry is accentuated by a series of shifting glulam frames creating a visually dynamic space”.

Internal timber surfaces are left exposed and stained white to complement the outdoor environment, visible through wrap-around glazing which “affords direct views from the water into the woodland, give the sense of swimming amongst the trees”, says Adam Cossey, partner at Hawkins\Brown.

Despite the extensive requirement for services and environmental controls presented by swimming pools, the building design was developed to allow the pool hall to appear to be relatively clutter-free, says services engineer Skelly & Couch. “All environmental control systems and water treatment plant were located and distributed around the perimeter of a subterranean base that in its centre housed the pool itself”.

Air is introduced to the space via discrete slots in the floor beneath the glazing, thus reducing condensation risk and evaporative heat loss from the pool. The design achieves a BREEAM rating of Very Good and offsets 10 per cent of its carbon using photovoltaics. In the next phase of works undertaken by the team at the school, a CHP energy centre will be introduced to the Grade II*-listed Main House which will use the pool as a heat sink.