The greenhouse effect and ozone depletion are two of the most critical environmental threats facing society. The heating, lighting and servicing of buildings account for approximately 50% of total UK energy consumption, which is directly linked to CO2 emissions (this does not take into account emissions produced by the manufacture of building materials). Furthermore, approximately 50% of total CFC’s produced are used in buildings for such uses as air conditioning, refrigeration, fire extinguishers and insulation. (Blowers, 1993)

The design of individual buildings for sustainability requires consideration of such issues as use of materials, energy efficiency and adaptability for future uses. In general terms vernacular styles of architecture will tend to produce more sustainable buildings than monumental styles due to the materials used and size and form of buildings.

A general principle for sustainable buildings is that they should be designed to be long life, low maintenance, energy efficient, adaptable to meet changing needs and be constructed of low energy, locally produced, renewable materials.

Flexibility is a key element of sustainability, as buildings are more likely to be re-used if they can be easily adapted to meet changing needs. “Long life - loose fit” developments will be encouraged. A building height of 4 storeys is sufficient to allow most activities whilst remaining compact and at a human scale and avoiding a reliance on the use of lifts. A mix of uses within a building can make efficient use of space, such as living accommodation above shops.



The extraction, processing, manufacture and transport of building materials can have a significant environmental impact (see Building Materials p18). The re-use of existing buildings should therefore be a priority. Most buildings are suitable for refurbishment which, in addition to reducing the need for construction materials, can offer an opportunity to upgrade insulation standards and heating, lighting and ventilation.

The key considerations are:

• think before you demolish. Can the building be adapted to meet present day needs?
• is there an opportunity to improve the energy efficiency of the building?
• all conversions and refurbishments should be designed to reduce energy use in proportion to the embodied energy of new materials used;
• the need to remove any hazardous materials present, such as asbestos.
  

Substructures and Basements:

• large areas of cut or fill should be avoided where surplus material must be transported to and from the site;
• consider the impact on surface water drainage and the existing water table;
• seek to minimise adverse impacts on soil resources;
• avoid damage to tree roots. Building foundations should be designed to reflect distances from trees;
• basements can provide useful additional space, but the above points must be considered;
• 'partial depth' basements provide for better natural lighting, ventilation and damp-proofing than conventional basements;
• providing a basement can enable more efficient use of individual plots, but should be carefully designed to avoid the creation of substandard living accommodation;
• basements can provide a substructure that is less susceptible to frost heave, settlement and moisture changes in the subsoil.

Walls:

• ideally, thermal insulation to above current Building Regulation requirements should be provided;
• good sound insulation is particularly important in high density developments, such as terrace housing and flats.
  

Windows:

• south facing windows should be large to maximise passive solar gain. However, in domestic buildings a balance must be reached between the size of windows and the need for privacy and security. The number and size of north facing windows should be kept to a minimum. Nevertheless, windows should be sufficient to provide natural lighting and ventilation;
• double glazing is now standard - consider the use of triple glazing;
• low emissivity glass can also be used to reduce heat loss;
• window frame materials affect thermal efficiency. This is particularly important for small windows. Timber frames have better thermal resistance than steel and aluminium (see also Building Materials ).

Roofs:

Pitched roofs have the following advantages over flat roofs:

• they generally require less maintenance;
• pitched roofs facing between 15o and 40o of due south provide an ideal location for solar panels;
• additional rooms can be created in the space provided by pitched roofs. To achieve this, however, trussed rafters should be avoided;
• steeper pitched roofs facing prevailing winds can help to break up wind flow.

Floor plans:

• living rooms should be orientated to the south to maximise solar gain. Kitchens, utility rooms, stairs, halls and bathrooms should generally be orientated to the north;
• in commercial buildings locate toilets, kitchen areas and storage space to the north of the building;

• design spaces that are flexible to enable easy adaptation to changing needs in the future. The location of stair wells and service ducts is particularly important as these features are expensive to change at a later date;
• provide for convenient and secure cycle storage within both commercial and domestic buildings;
• provide storage areas for containers for recyclable materials.

Conservatories and Porches:

• locate conservatories on south, west or east facing walls. The conservatory should not be heated and there must be a properly insulated wall between the conservatory and the house;
• draught lobbies / entrance porches should be used to reduce heat loss through external doors.

Heating:

• consider the use of active solar technology for heating or power generation;
• use the smallest appropriate system to enable use at optimum efficiency. High efficiency condensing boilers should be considered;
• gas is cleaner and generally more efficient than electricity. However, this may change as the proportion of electricity generated from renewable resources increases;
• use a system that is adaptable to different fuels in the future - this will be particularly important as technologies that exploit renewable sources of energy are developed;
• the heating system should be capable of being upgraded to include heat recovery from waste air / water and ambient sources of energy. This is particularly relevant in commercial and industrial buildings;
• timers and individual radiator thermostats should be provided;
• provide flues with heat exchangers;
• Energy Management Systems should be used in commercial buildings.

Lighting and Ventilation:

• maximum use should be made of natural lighting and ventilation. A plan depth of up to 13m allows for natural daylighting and ventilation from windows on both sides;
• the use of atria and glazed courtyards in larger buildings will increase natural lighting levels and can be used to induce a stack ventilation effect - but these spaces should not be fully heated;
• large single storey buildings can be designed with rooflights to introduce natural daylight;
• minimise the use of air conditioning. If air conditioning must be used, specify a low energy system and install a heat exchanger;
• wind towers, associated with a central atrium, can be used to provide natural ventilation for larger buildings, such as offices and shopping centres;
• Building Management Systems should be installed to ensure that passive and active environmental systems are operating as efficiently as possible;
• use energy efficient, compact fluorescent lighting;
• maximise the use of timing and intensity controls for lighting.
  

Water Use and Conservation:

• minimise the use of ‘white water’ by installing a system for ‘grey water’ recycling for toilet flushing;
• provide facilities for collecting rainwater for recycling as ‘grey water’ for watering plants;
• install efficient appliances that enable reduced water consumption;
• fit low volume flush WC’s and flow restrictors to taps;
• provide facilities for heat exchange from waste water;
• consider the use of a reed bed system for foul water treatment;
• composting toilets may also be appropriate for some schemes.

Reducing Heat Loss:

• compact dwellings, such as flats and terraces, reduce the surface area for heat loss. Such dwellings also provide flexibility for changing patterns of household formation;
• the potential to link buildings should be explored for non-residential developments;
• thermal buffering can be provided by attaching conservatories, garages and greenhouses to the outside of heated rooms;
• all windows and external doors should be draught sealed. For commercial buildings with large doorways, air lobbies can be used to reduce heat loss;
• on sloping sites, buildings can be cut into the slope;
• earth sheltered buildings should be considered. These provide good sound and heat insulation and can reduce impacts in sensitive locations;
• conversion and/or refurbishment of existing buildings can offer an opportunity to improve their energy efficiency.

Green Buildings

• planting on walls helps to reduce heat loss and airborne dust and can provide a wildlife habitat;
• trees near buildings provide shelter and shade (but do not plant trees closer than recommended distances in Residential Design Aid 4)
• green roofs can provide a useful wildlife habitat, particularly in urban areas and can reduce levels of roofwater run-off. Where possible use extensive, low maintenance systems.

External lighting is an important aspect to consider in design. It can be difficult to get right and therefore it needs to be designed carefully and precisely. A well designed lighting scheme has a number of benefits including increased safety and security and the enhancement of architectural and landscape features after dark. However, lighting can be detrimental to the environment through light pollution, and its impact on amenity, the night skies and wildlife, and through the energy required for the lighting itself.

Careful consideration should be given to the environmental impact of external lighting schemes:

• lighting levels should be the minimum necessary to achieve safety and enhancement objectives;
• energy efficient lamps should be used wherever possible;
• uncontrolled floodlighting should be avoided and all light fittings should be shielded to minimise any light pollution;
• particular care should be taken with floodlighting schemes for sports pitches which can have a detrimental impact on local amenity.

For more detailed guidance on lighting schemes developers are advised to refer to ‘The Lighting Code of Practice’ published by the Department of Planning.



The materials used in any development can have an important influence on sustainability. It is important to consider the source of the materials (are they from finite or renewable resources?) and the energy used in both their manufacture and transportation. Buildings often consume more energy through their materials and construction than they do throughout their lifespan. This is particularly the case with commercial buildings which are generally constructed of high energy materials, such as steel, aluminium and glass, and tend to have a short lifespan before major refurbishment. It is important therefore, that maximum use is made of any existing materials on site, recycled materials and of low energy materials - those that are available locally, are naturally occurring and/or a by-product of some other local activity. Innovative schemes using low impact materials will be welcomed.

• earth is probably the most sustainable building material as it requires no energy in its manufacture and can provide high levels of insulation. In addition, earth sheltered buildings tend to have a reduced impact on the landscape and can provide opportunities for habitat creation;
• other natural materials, such as straw, cork and hemp can be used to create low impact building and insulation materials;
• timber is generally considered to be a low energy material, however care must be taken to ensure that it is sourced as locally as possible and is from well managed, independently certified sources (NB. at present approximately 95% of the timber used in construction is imported). Timber also has the benefit of locking up atmospheric carbon;
• stone - the benefits are that it is durable, easy to recycle, low maintenance and has a high thermal capacity. However, consideration should be given to the need for transportation and the impacts of extraction;
• bricks have a high energy input into their production but are generally durable and re-usable. Locally produced bricks should be specified to reduce transport costs;
• materials such as plastic, steel and aluminium require a high energy input in their manufacture and thus should be used sparingly. PVCu, in particular, is energy intensive in its manufacture, is difficult to re-use and recycle and therefore should be avoided if possible;
• insulation requiring the use of ozone depleting gases should be avoided;
• avoid over - specification. Recycled materials should be used wherever possible rather than virgin materials. These may result from demolition on site or may be imported from elsewhere;
• products such as cement and lightweight concrete blocks can be made using waste or by-product materials. These should be specified.
• avoid specifying materials which cannot easily be separated for re-use/recycling.

Building Regulations requirement L.1 deals specifically with the conservation of fuel and power by requiring provision to be made within buildings for:

• limiting heat loss from the building;
• controlling the operation of space and water heating;
• the insulation of heating systems and hot water storage systems;
• the installation of energy efficient lighting systems in certain large premises.

The current “Approved Documents” to the Building Regulations encourage developers / designers to adopt energy saving provisions such as the use of higher efficiency heating systems and taking account of solar gains, by considering the orientation of the building and glazed areas.

In addition, the City Council will encourage the use of energy and water efficient appliances.



Standard Assessment Procedure (SAP)
There is a statutory requirement under the Building Regulations for all new dwellings to be provided with an energy rating using the Government’s Standard Assessment Procedure. New dwellings are assessed on a scale from 1 to 100 - a higher score indicating greater energy efficiency. There is no requirement to achieve a minimum rating under the Building Regulations, however developers will be encouraged to consider the final energy rating at an early stage in the design process and to seek to achieve a rating of 80 and above.

This method does not apply to non-residential development.

National Home Energy Rating (NHER)
The NHER also provides an assessment of the energy efficiency of a dwelling based on a wider range of issues than SAP ratings. These include orientation, location, altitude, size, fuel type, heating and hot water system and household appliances. A scale of 0 to 10 is used, with a higher score indicating a more energy efficient home. (A score of 7 conforms to current Building Regulations)

Environmental Standard Award
The Environmental Standard Award is administered by the Building Research Establishment (BRE) and is intended to provide an indication that a development has reduced its impact on the environment. New homes are assessed under a range of criteria including emissions of greenhouse gases and CFC’s, use of materials, site ecology, water use and levels of comfort.