Name & Location: Sharrow School, Sheffield
Introduction: The new junior and infant school building was designed to integrate with the surrounding landscape of Mount Pleasant Park, and to make a bold statement about the school’s commitment to sustainability. Each classroom has access to outside space, daylight and natural ventilation as well as innovative opportunities for outdoor play, linking recreation to learning.
The school’s sustainable features include: a ground source heating system, a rainwater harvesting system and a passivent system to minimize the need for mechanical ventilation. The green roof provides added value by assisting with the control of storm water, humidity, noise, heat and pollution. A byproduct of this was to create a haven for local wildlife using recycled material.
Main principles of the design concept included:
- Low input - no irrigation or fertiliser
- Use of locally sourced recycled materials
- Make the most of the structural capacity of the roof
- The use of volunteers and local enterprises
- Reflect local habitats
- Educational opportunities
- Visually stimulating and colourful
The roof’s planting scheme was designed by Dr Nigel Dunnett of the University of Sheffield, and features a pond, drystone walling and a weather station for research to be compiled at the University. It was sewn with wildflower seed mix from Pictorial Meadows. Plants used included directly sown annuals for high visual impact (i.e. cornflowers), limestone grassland mix, roof meadow mix (i.e. urban brownfield site snap dragons etc) and natural colonisation. Mixes contained no grasses due to their invasive nature.
The substrates used were 150m³ (200t) of crushed brick mixed with 20% green waste and 22m² of limestone supplied by Tarmac. The limestone was topped with loam to encourage propagation.
The minimum loading allowed on the roof was 150kg/m² meaning a substrate depth of 100mm substrate could be used. Places with extra loading capacity i.e. near support beams could hold up to 250kg/m². Here graduated mounds were used to give an average of loading requirements and create different habitats and aspects. The roof light also serves to splits up the roof into north and south habitats.
Green Roof Type: Wildlife
Green Roof System: Bauder
Roof Size: 1800m²
Roof Slope: 1 in 60
Green Roof Contractor: Kier and Green Estate Ltd
Main Contractor: Kier
Architect: Cath Basillio – Sheffield City Council
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