Project Overview:
Background:
Kings Mill Hospital is an NHS general hospital set between Sutton-in-Ashfield and Mansfield in Nottinghamshire. It serves north Nottinghamshire and parts of both Derbyshire and Lincolnshire. The largest of three sites managed by Sherwood Forest Hospitals NHS Foundation Trust, the building is notable for its colourful exteriors. However, the external cladding and render systems were designed to be of more than just aesthetic value: they also provide valuable insulation to minimise the hospital’s energy use and costs.
The Brief:
The new hospital, occupying a site of 120,000 m2, would be designed to encompass 28 wards in three T-shaped ward blocks linked together over 5 floors. The wards rise above a state-of-the-art diagnostic and treatment centre, an emergency care centre and a ‘women's and children's centre.’ Procurement for the £320 million new-build scheme was undertaken under a PFI initiative with Skanska Innisfree PFI Consortium, and the building was designed by architects Swanke Hayden Connell. Work was scheduled to complete in 2011.
A key element of the design was to bring natural daylight into the building’s interior. This would create bright, inviting circulation spaces and enhance the building’s energy efficiency. In addition, the largest geothermal lake loop scheme in Europe, provided 90% of the cooling for the building using heat exchangers at the bottom of King’s Mill reservoir. The use of an external wall insulation (EWI) system would also be essential for achieving a thermally efficient external envelope.
Design and Specification:
The architect’s design specification called for PermaRock’s Mineral Fibre EWI System to be installed on the external walls, which comprised of a cementitious sheathing board over light steel framing. Traditional cavity blockwork walls, which did not require externally insulating, were treated with the PermaRend Exterior Render System, finished with the same PermaRock Silicone and Acrylic K-Finish decorative renders used throughout the insulated render areas.
External wall insulation with white and colourful render finishes was also applied to the walls of the internal circulation areas under the large glazed atrium.
Sherwood Forest Hospitals NHS Foundation Trust had appointed colour artist, Ptolemy Mann, to specify the colours for the façades of the building. He approached the design by visualising the façade as a large-scale woven artwork using render, powder-coated metal and glass instead of threads, replicating a ‘macro-zoom’ into the structure of cloth. This made PermaRock’s Silicone and Acrylic K Finishes an ideal choice. These textured renders, available in a range of over 1300 colours from PermaRock’s 3D-Plus colour range, provided the freedom of colour expression demanded by the design. On the external façades, they also promised excellent weather resistance and durability as well as very good colour fastness.
The renders were applied in rectangular blocks of colour, mimicking the metal cladding panels used on the upper elevation walls. Each colour panel was separated from its neighbours by a faux shadow gap detail, created in the render system using a black silicone resin-based coating and a masking technique.
Used in conjunction with PermaRock’s non-combustible (Euroclass A1) mineral fibre insulation, the render and insulation combination created a system that not only met the thermal and fire performance requirements but also helped the architect realise the colourful façade design.
Result:
The new-build hospital was completed in 2011 and, since then, it has retained its bright and striking appearance. Moreover, the facility has demonstrated excellent sustainability and energy efficiency. The architects reported that the hospital “was awarded a BRE NEAT ‘Excellent’ rating, based on numerous integrated design features,” and estimated that “integrated engineering and passive eco design” would reduce the hospital’s carbon footprint by 400 tonnes a year.