Elizabeth II Court for Hampshire County Council, Winchester

Elizabeth II Court for Hampshire County Council, Winchester

Provided by Bennetts Associates   

 

Exterior

The remodelled facade introduces rich articulation and local materials whilst forming a key element of the innovative low energy strategy. © Tim Crocker.

Awards: RICS ‘Sustainability’ Award (Regional - South East)
BCO Regional Award for ‘Refurbished/Recycled Worksplace above 2000sqm’
‘Sustainable Project of the Year’, Building/UKGBC Sustainability Awards - 2009
Shortlisted ‘Public Building of the Year’ Building - 2010

Architect: Bennetts Associates Architects

Address of project: Elizabeth II Court, Winchester, Hampshire SO23 8UJ

Construction Cost: £29 million 

Year of Completion: 2009

Client: Hampshire County Council

Quantity Surveyor: Davis Langdon

Structural Engineer: Gifford

Services Engineer: Ernest Griffiths

Main Contractor: BAM

 

 

 

 

 

The design problem

The Elizabeth II Court project (formerly Ashburton Court) in central Winchester represents a groundbreaking transformation of a dilapidated 1960s office block into a modern, efficient and highly sustainable working environment for continued occupation by Hampshire County Council (HCC).

The building has traffic on three sides, restricted floor-to-floor to ceiling heights and most main elevations façades facing east and west, which are difficult to shade. The original building was also uncomfortable to occupy, suffering from overheating in summer and a huge heating requirement in winter.

The project presented an opportunity to create a benchmark addressing a universal challenge – the creative re-use of 1960s building stock.

 

Original facade

Original 1960s façade at odds with the surrounding buildings. © Bennetts Associates.

 

The tranformed building

The transformed building sits more comfortably with the scale, rhythm and materiality of Winchester. © Tim Crocker.

 

 

 

The site

The building tranformed II

The transformed building sits more comfortably with the scale, rhythm and materiality of Winchester. © Tim Crocker.

Winchester is one of the UK’s finest historic cities with a rich urban grain and a plethora of significant buildings and spaces. Whilst demonstrating a diversity of styles there is a harmonious background quality of scale, articulation and use of materials.

Elizabeth II Court (then referred to as Ashburton Court) suffered from an aggressive external presence which jarred with the sensitive historic context and had attracted national notoriety. The new design articulates the building in a more sensitive manner through reduced massing, new elevations and use of local materials. A new scale, rhythm and modulation has been introduced which softens the presence of the building and relates to the rich architecture of the city. The façades also connect the upper building with the street and suppress the presence of the remaining car parking.

 

The architectural response

The existing building was stripped back to its structural concrete frame. Then in order to allow wind driven ventilation, ducts were placed on the outside facades. Ventilation air is drawn into the building from the courtyards, across the floorplate and then up acoustically attenuated ventilation ducts on the street facades of the building. The ‘wind troughs’ on top of the ducts exploit wind blowing across the roof to create suction, which draws air through the building.

The brick clad ventilation ducts also helped to shade the east and west facades and to bring a more appropriate scale and rhythm to a building that had been very horizontal and disconnected from the street.

 

Wind tunnel modelling

Wind tunnel modelling with wind pressure sensors. © Bennetts Associates.

Wind tunnel results

Wind tunnel results showing pressure differentials between each wind-trough and associated courtyard windows for 16 points of the compass. © Bennetts Associates.

Ventilation systems annotated

Exploded diagram of new ventilation system. © Bennetts Associates.

 

Graph

Per occupant impacts for commuting, operational and embodied energy modelled over 40 years. This shows that once natural ventilation has been implemented and the building moved closer to city centre transport links then embodied energy becomes much more significant. © Bennetts Associates.

Sectional perspective

Sectional perspective through Elizabeth II Court. © Flashforward.

 

 

The building

Ground floor plan

Ground floor plan after refurbishment. 
© Bennetts Associates.

Cross section

Cross section after refurbishment. 
© Bennetts Associates.

West elevation

West elevation after refurbishment. 
© Bennetts Associates.

 

Podium level

Podium level as it used to be, an unwelcoming environment with car parking and hidden entrances. 
© Bennetts Associates.

Podium level

The podium level transformed with a welcoming new entrance and communal facilities laid out around tranquil courtyards. 
© Tim Crocker.

Previous environment

‘Institutional’ environment prior to refurbishment. 
© Bennetts Associates.

 

Office interior

Transformed modern office interior and diversity of space supports flexible working. © Tim Crocker.

Office interior

Transformed modern office interior and diversity of space supports flexible working. © Tim Crocker. 

Facilities

Internal street and new communal facilities form a social heart to the building and the organisation. 
© Tim Crocker.

 

Facilities

Internal street and new communal facilities form a social heart to the building and the organisation. 
© Tim Crocker.

 
 

 

Design strategies

  • Embodied energy: With low energy buildings embodied energy can account for as much as 20% of the lifecycle environmental impact. The project re-uses the existing in-situ concrete frame. The foundations and structural frame account for approximately half the embodied energy of a building.
  • Cross ventilation: Though the diagram looks like stack ventilation it is in fact cross ventilation, as wind is more a powerful driver of ventilation during summer days. Open topped ‘wind-troughs’ create suction at the top of the ventilation ducts (irrespective of wind direction), which draws air from the court yards and across the floorplates.
  • Night ventilation: The thermal mass of the existing building was exposed and painted. At night during the summer the building is then ventilated using automated opening windows. During the day the cool structure then creates an additional 25w/m2 of cooling, which soaks up heat from occupants, computers, etc.
  • Solar controls and shading: The main facades face east and west, which are both difficult to shade due to low angle morning or afternoon sun – this requires vertical rather than horizontal solar shading. The majority of solar shading is provided by the depth of the ventilation ducts, with additional vertical louvre blades.
  • Controls and building management systems: On courtyard facing facades half of opening windows are controlled by the BMS, while there remainder are occupant controlled. It is important to allow some user control and also extensive work was carried out explaining the building and writing simple guidance documents. The control of lighting is also important in reducing both energy use and heat gains and to this end the internal lights have daylight and motion sensors.
  • Noise control: The building is surrounded on three sides by heavily trafficked roads. This prevented a reliance on ventilation using opening windows on the street facing facades. The ventilation ducts and wind troughs allow wind driven cross ventilation without needing to open street facing windows.

 

Lessons learned

The occupation of the first phase in January 2008 was a great success, particularly considering the timescale constraints within which the detail of the move had to be resolved. Key to this success was the quality of planning and approach of the client, professional team and contractor combined with the enthusiasm of the occupying department to embrace the approach. This greatly benefitted the recent large scale occupation of the second phase and staff have settled in quickly to their new environment and way of operating. On-going support is being provided for the settling in period via a new and proactive facilities management regime. The model created is now being rolled out countywide through the ‘Hampshire Workstyle’ programme and has attracted a great deal of interest from other local authorities.

 

Related case studies

Embodied energyNatural ventilation - cross ventilationNight ventilation - thermal mass, Solar controls and shading, Noise control

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