Britain’s greenest buildings
The bar for sustainability is noticeably higher among this year’s RIBA Award-winners, write Hattie Hartman
Over a third of this year’s winners are examples of best practice - a step change from three years ago. The need to get form and fabric right is much more widely understood. Even those projects where aesthetics, rather than sustainability, are the driver have been ramped up by solid environmental engineering.
Now a mandatory part of RIBA Awards submissions, the project sustainability statements read as informed commentary rather than, as often used to be the case, a litany of sustainable features.
And in Scotland, where a sustainability statement is not mandatory, RIAS secretary Neil Baxter observes that ‘the standard has improved markedly over the last five years. Any architect who does not maximise sustainability in a project is not doing his or her job. You don’t need to ask for it any more.’ Last year the RIAS awarded a sustainability prize - supported by Zero Waste Scotland - for resource-efficient design. Though it was dropped this year, sponsorship is now in place to reinstate the award from next year.
Thoughtful retrofit continues to be a hallmark of the RIBA Awards. Amin Taha Architects’ subtle transformation of 115 Golden Lane, a listed 19th-century building in Islington’s St Luke’s Conservation Area, stripped away years of accretions to reveal original structure and details.
Another trend is the increased use of cross-laminated timber (CLT), well-established in schools such as Hawkins\Brown’s Ritblat Building at Hilden Grange Prep School in Kent. Hugh Strange’s Architecture Archive takes CLT to a new level, employing 300mm-thick wall panels and 420mm-thick roof panels with no additional insulating material to create a temperature-stable environment for archives.
My green picks of 2014 are not the obvious choices. I grant that, with their BREEAM Outstanding badges (not easy to get) and integrated design approach, both O’Donnell + Tuomey’s Saw Swee Hock Student Centre at the London School of Economics (AJ 28.02.14) and Hopkins Architects’ Brent Cross Civic Centre (AJ 01.08.13) are clear candidates for the top slot. But I’ve left these exceptional projects aside because they have previously featured in these pages. Hopkins’ rigorous approach to integrated design has been repeatedly documented in the AJ with projects including the London 2012 Olympic Games Velodrome (AJ monograph 09.11), Kroon Hall (AJ 27.05.10) and WWF-UK’s Living Planet Centre (AJ 29.11.13). In a surprising oversight, the latter, pioneering in its approach to reducing embodied carbon through a laborious carbon accounting process, was bypassed by its regional jury this year.
This year’s best green buildings are presented on the following pages with predicted emissions data for each. Ironically, the higher green bar made it much tougher to spot the truly innovative projects. Four are highlighted: two by established architects not known as sustainability pioneers, and two by up-and-coming practices.
Ortus, Denmark Hill, London by Duggan Morris Architects
This learning hub for a mental health charity at the Maudsley Hospital in London exploits passive design without reeking of sustainability. The building is organised around an atrium, which enables a stack effect, with automated vents in the facade introducing fresh air. A grand staircase links daylight-filled spaces on different levels. Every space has CO² monitoring. A thorough approach to sustainability includes 50 per cent ground-granulated blast-furnace slag (GGBS) cement substitution in the concrete, while plywood with paper facings was used to achieve finishes. Ribbed concrete slabs increase thermal mass. Photovoltaics (PVs) and eight 120m-deep boreholes are predicted to further reduce energy demand. The team is using Soft Landings as a commissioning process.
TNG Centre, Lewisham, London by RCKa
Out of a lengthy community consultation process came a brief to provide robust, flexible space that would be adopted and valued by its youthful constituency. Passive design and cross-laminated timber drive down both operational and embodied carbon to deliver a low-energy building. Oriented north-south, an unheated winter garden flanks the building’s long eastern side and acts as a thermal buffer. Generous window configurations plus rooflights bring in plenty of daylight. Actuated vents within the window panels can be overridden manually for comfort. Most of the building can be naturally ventilated using the stack effect of the vertical section configuration. Sinusoidal polycarbonate cladding and energy-efficient light fittings make it a beacon of activity after dark.
Everyman Theatre, Liverpool by Haworth Tompkins
The brief called for energy efficiency in construction and in use. Haworth Tompkins rejected the findings of an earlier feasibility study recommending a new building elsewhere, opting for a compact building in the same location. With passive design informing the massing, location and glazing, thermally massive construction is combined with roof vents and an underfloor plenum to naturally ventilate performance space and offices. Its BREEAM Excellent rating is quite an achievement for a theatre in a dense urban location. A concern with materiality pervades the project; apparent in the salvaged 19th-century bricks which wrap the auditorium. A gas-fired CHP unit is estimated to reduce operational CO² emissions by more than 25 per cent, and post-occupancy monitoring is planned.
One Pancras Square, London by David Chipperfield Architects
The predicted annual emissions of this pioneering office development are remarkably low, particularly for a speculative office building. The King’s Cross district heating system helps, reducing predicted emissions by a third. A 230m² array of rooftop PVs knocks off another 17 per cent. Passive design features of the building include a narrow 7.2m-wide facade-to-core dimension (assisting daylight penetration), a glazing ratio optimised by thermal modelling, exposed concrete floor slabs and, unusual for this building type, occupant-controlled full-height vertical perforated panel openings in the facade. Tenants can opt for natural ventilation, enhanced natural ventilation with an extract system, or full mechanical ventilation via chilled beams.
Golden Lane by Amin Taha Architects
Described by the jury as an ‘exquisite tactile gem’, Amin Taha Architects’ transformation of this listed building in an Islington conservation area exemplifies an attitude towards refurbishment that can be replicated in countless buildings across the UK. The approach is simple: strip back and reveal the building’s original historic fabric and introduce striking contemporary features. The poetry is in the detail, including entrance portals and a security screen. Passive environment controls meet 90 per cent of the heating and cooling loads.
Scottish Water - The Bridge by Reiach and Hall Architects
Reiach and Hall Architects’ 7600m² out-of-town office building for Scottish Water in Lanarkshire uses passive measures to meet a demanding environmental brief. Wrapped around a central atrium, the open plan offices are organised so that no desk is further than 6m from the perimeter, ensuring good daylight and ventilation for all workspaces. A double-height masonry colonnade projects to shade the south and west elevations, while on the north facade, the overhang is minimal.
Manor Works by Architecture 00
In addition to an innovative social enterprise programme of managed workspace and community uses in a deprived area of Sheffield, Manor Works exemplifies Architecture 00’s holistic approach to sustainability: a long-life, loose-fit framework informed by passive design, fabric first principles. Clad in a perforate metal screen intended as a growing surface for plants, the aspiration is that native planting will clamber over the building, integrating it with its sloping site.
Britten-Pears Archive by Stanton Williams
Located on the grounds of Benjamin Britten’s Grade II-listed home in Aldeburgh, the BREEAM Excellent-rated archive is described by the architects as an ‘egg in a box,’ with a well insulated brick exterior enclosing a concrete blockwork storage room. A thermal buffer space between the two moderates temperature and humidity. Windows and rooflights provide ample daylight to naturally ventilated staff and visitor areas. Timber wall linings create a warm and elegant interiors for archive staff, researchers and visitors.
Porthemor Artists Studios by Long & Kentish Architects
At these Grade II*-listed artists’ studios in St Ives, Cornwall, Long and Kentish have taken a light-touch approach to refurbishment, described by the jury as ‘raw modesty’. The merit of each improvement was carefully assessed, weighing environmental upgrade against loss of character. Windows were repaired rather than replaced, stone and concrete walls were not thermally upgraded to retain their character, and corrugated plastic skylights were replaced with double glazed greenhouse glazing in timber battens.