Sustainable Design & Construction 

Since the design and construction of the Bishops Wood Environmental Education Centre in 1993, Property Services have adopted design policies which deliver new public buildings that not only meet and exceed statutory targets, but also incorporate sustainable design features at affordable cost. 

As a consequence, the Design Team routinely deliver award-winning, low-carbon buildings that  demonstrate excellence  in terms of sustainability, energy efficiency and resilience to future climate change, all within standard cost allowances.

The County Council's architects took the opportunity to use the Bishops Wood project as a test-bed for a number of cutting-edge technologies, and incorporated breathing walls in a highly-insulated timber construction with thermal insulation made from recycled newspaper. 

The building is naturally ventilated, a central masonry core provides thermal mass for limiting summertime temperatures. Waste water is treated via an on-site reed bed, a solar hot water system serves the WC facilities, and rainwater is harvested and passes through a Sustainable Urban Drainage. These and other technologies have been tried, tested and evaluated and now feature in the majority of new projects designed by the Council's in-house design team and its consultants.

The inherent sustainable approach to design commences with the site, its existing shape, features, orientation and gradients, and the resident flora and fauna. Detailed feasibility studies are undertaken, using a standardised methodology and using a variety of modern computer-aided design tools, and a number of options will be prepared for appraisal. 

Building orientation on the site is a vital element in achieving the lowest cost in use, in terms of maximising daylight and beneficial solar gain and  consequently reducing the need for artificial lighting, heating and cooling.

Materials used in the construction of the building can be judiciously selected to reduce the amount of embodied energy and to increase the potential for recyclability when the building is eventually demolished. 

The re-use of demolition materials and  other wastes from existing structures on site is incorporated, using WRAP protocols, ensuring that the use of virgin materials and waste sent to landfill are both minimised. Red Hill Primary School, completed in 2007, incorporates 26% of recycled materials within its construction, and all the rubble from the demolition of the old buildings on      the site were incorporated in the foundations of the new school.

The Council gives priority to the use of materials which have the lowest lifetime environmental impact. Hence structural timber is preferred to steel or concrete, PVC  and other oil-derived plastic materials are not used, timber door and window frames and solvent-free paints are specified, and floor coverings made from natural materials such as linoleum are preferred to vinyl. 

The Design Unit approaches electrical and mechanical services design in a holistic way, with engineers and architects liaising from the earliest feasibility stage throughout the design and construction. Engineering services create the bulk of the lifetime CO₂ emissions from buildings, and whilst the energy performance of these  services is controlled by Building Regulations, good design can reduce the impacts further. 

Preference is always given to integrated design solutions that will inherently reduce the lifetime carbon emissions and limit reliance on mechanical plant. Buildings are designed to reduce reliance on external service connections, particularly storm water drainage, and incorporate features such as sustainable urban drainage systems, swales, on-site flood zones and green roofs in order to adapt to the increased frequency and severity of rainfall events that result from climate change.

This combination, together with rainwater harvesting systems enables rainwater to be retained on the site, attenuate run-off and minimise or even avoid the need for a public storm water drainage connection.

The final action and priority of the 'energy hierarchy', after reducing energy demand and wastage as much as possible and maximising the efficient use of energy, is the exploitation of low- or zero-carbon (LZC) energy technologies in order to reduce further the use of fossil fuels. 

Since 1996, the Design Unit has incorporated a wide range of such systems, including wood-chip and wood-pellet boilers, ground source  heat pumps, solar PV and solar thermal systems in building projects, and evaluated  the cost-effectiveness of each in terms of the lifetime cost of carbon saved.

By the end of 2009-10, the Council is on target to have installed 1,500kW of biomass boiler capacity, and over 150kW of ground source heat pumps, providing an ongoing  overall emission reduction of some 800 tonnes of CO₂ each year across the estate.

In addition, this has resulted in exemplar buildings, such as Red Hill Primary School which is within the top-performing 10% of low-energy schools in the UK.

This page was last reviewed 4 October 2012 at 15:13.
The page is next due for review 2 April 2014.