Green generation: as a champion for a greener ethos in school design, Cottrell & Vermeulen Architecture has put its theory on sustainable refurbishment to the test at Westborough School, Westcliff-on-Sea. Photography by Anthony Coleman
Cottrell & Vermeulen Architecture is at the forefront of British school design. From the Krishna-Avanti Primary School in Neasden, north London, to the Cardboard Building at Westborough Primary School in Westcliff-on-Sea, the firm has been instrumental in helping to improve the culture behind designing for education, with a particular focus on energy reduction.
Its latest work sees the firm returning to Westborough, a site it has been developing for nearly two decades. The recently completed zero carbon refurbishment has been jointly funded by Southend-on-Sea Borough Council’s Primary Capital Programme and Department for Education. The works, conducted under the architects’ lean, mean, green approach, provide a test bed for ways to refurbish older school buildings in a sustainable way. There was a 90 per cent reduction target for carbon emissions, with a range of active and passive strategies to save energy.
The focus of the project is the school’s Edwardian redbrick main building. The buildings have been modernised to meet current academic requirements, with improved insulation and acoustic lining in the hall, and the main school entrance redesigned with a new reception and waiting area with improved access. New playground cabins can be used for both play and storage and a canopy along the back of the school provides a circulation route that supports photovoltaic panels. Monitors around the school display energy use and carbon emissions.
Richard Cottrell says there is an urgent need for a better understanding of how to affordably and efficiently refurbish schools. ‘Studies show that new builds can emit over four times more CO2 than refurbishments. New builds meeting current standards could take up to 50 years to catch up with refurbishments in terms of repaying their carbon debt through lower operational emissions.
Read the environmental performance data for Westborough School
Start on site November 2009
Contract duration 14 months
Gross internal floor area of refurbishment 948m²
Gross area of playground stores and canopy 292m²
Form of contract/procurement Negotiated two-stage tender/Building contract JCT ICD 2005
Total cost £1.35m
Cost per m2 £1,088.71
Client Southend-on-Sea Borough Council and governors of Westborough Primary School (also partially funded by Department for Education
Architect Cottrell & Vermeulen Architecture
Structural engineer Engineers Haskins Robinson Waters
M&E consultant OR Consulting
Sustainability consultant Buro Happold
Main contractor Balfour Beatty Construction
CDM co-ordinator BZ Consulting
Approved building inspector MLM Building Control
Quantity surveyor Stockdale
Estimated annual CO2 emissions 18kg/m², phase 1 of refurbishment (previously 40.1kg/m²)
Lean, mean and green Cottrell & Vermeulen Architecture’s low-carbon strategy at Westborough School
LEAN INTERVENTIONS TO REDUCE ENERGY DEMAND
Insulation of existing walls Insulated Drylining board added to improve the thermal performance of existing external walls. Insulation of roof and introduction of inner roof lining Insulation bonded to the existing internal surface will improve both thermal and acoustic performance of the roof. Installation of secondary glazing A combination of double glazing and internal secondary glazing improves thermal performance. Improvement of building air tightness Control airflow through existing roof vents and ensure windows and doors are properly sealed. Insulated distribution pipework Hot water and heating pipework has been insulated to reduce losses and improve control.
MEAN INTERVENTIONS TO SUPPLY DEMANDS EFFICIENTLY
Modification of fluorescent lights to use T5 lamps Existing fluorescent light fittings modified to accept more efficient T5 lamps. Energy consumption reduced by 45 per cent. Lighting control PIR/Daylight sensors used to control classroom lighting. Computer energy management Improvements to energy management of existing IT infrastructure. Optimised scheduling of heating plant operation New boiler controllers allow optimised scheduling to reduce unnecessary running hours. Hot water alternative generation Providing ‘regional’ water heaters reduces hot water carbon emissions by up to 50 per cent. Submetering and energy management Submetering of energy consumption will allow a detailed image of how and where energy is consumed. Heat Exchange Heat exchange systems
have been installed to maximise energy use within the ventilation and heating systems.
GREEN INTERVENTIONS TO USE RENEWABLES
Solar Photovoltaic Solar photovoltaics have been installed on the south facing pitch of the roof structure. Outputs from a typical, UK-based, solar photo voltaic array can achieve yearly electrical yields of approximately 100 kWh/m2/year. Biomass boiler As an alternative to gas boilers, a biomass boiler is a way of meeting the school’s heating demands. The school currently uses 150kW. By installing a biomass boiler, it is estimated that 66 per cent of annual heating carbon emissions will be saved.
Rainwater harvesting A rainwater harvesting tank has been installed for toilet flushing.