Knox Bhavan’s pavilion nestles into the protected landscape of Cassiobury Park


Fergus Knox

The Cassiobury Hub is a significant new multi-purpose building in Cassiobury Park in Watford. As well as providing a destination for the 190-acre park’s several thousand annual visitors, the building will help to ensure that the important landscape can be managed in a sustainable and coherent manner for years to come. Designed by Knox Bhavan Architects to sit within rather than on the landscape, the structure is set into the natural slope of the land, minimising its impact and making it appear as a quiet single-storey structure when viewed from the south. From the north, however, the full extent of the building, together with the concrete podium upon which the terrace sits, is revealed. Materials were chosen to be in harmony with the parkland landscape, with colour, texture, reflection and energy consumption all thought through.


Inside, the first-floor terrace houses the exhibition and education space which can be subdivided using large sliding doors. A cafe and balcony on this level overlook the popular paddling pools below, while full-width north-facing clerestorey windows provide abundant natural light. Sliding, laser-cut Corten steel panels to the exterior can be positioned across the face of the floor-to-ceiling openings to provide both shading and security. Perforated in an abstract pattern (referencing a fine cedar tree nearby) shafts of light penetrate the Corten and add interest internally.

The ground floor accommodates public toilets and sports and pool changing rooms. The service yard – for vehicles, refuse, plant, and storage – are tucked away behind the public-facing area. Flush thresholds, accessible toilets and changing rooms, all with non-slip surfaces, ensure access for all.


The grade-two registered landscape was compromised in the latter part of the twentieth century by unsuitable yet popular additions such as the paddling pools and associated structures, but the award of a substantial grant from the Heritage Lottery Fund in 2013 provided the opportunity to restore undertake a restoration and remove the latter eyesores yet retain the popularity of such facilities.

A cornerstone of Watford’s ambition – and the HLF funding – was that the Hub should be an exemplar in terms of energy use and sustainability. The building was therefore orientated to incorporate photovoltaic panels on the south-facing roof, built with robust, self-finish materials such as Corten, larch and concrete gabions for durability, and highly insulated. A brise-soleil and overhangs protect the windows from overheating and glare and a rainwater-harvesting tank collects water for flushing toilets. The lower ground floor is unheated and uninsulated along its perimeter, creating a buffer zone to the spaces at the centre, which are heated by a low-energy air-source heat pump and help maintain a constant temperature. A planted roof reduces rainwater run-off and increases biodiversity.

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