Modern materials, design and technology allow many opportunities to minimise the impact of the process and results of construction on the environment. The following principles reflect our desire both to protect the environment and ensure the best and create an ideal and cost-efficient design for you. We will therefore discuss the following principles with you early on in the design process.
Use natural, renewable and/or or reusable materials which minimise energy used in their manufacture. Examples include slate, natural stone, timber from sustainable sources, leather, cork (for insulation and flooring), linoleum, renewable textiles and wool carpets. Consider using of timber-framed buildings: they are light and require less foundation material than masonry buildings, they avoid the need for plastering, use much less energy in construction and are easily adapted. Check the health risks associated with man-made mineral fibres. To combat global warming we need to restrict the use tropical hardwoods to those from sustainable forests, avoid ozone-depleting gases and design energy-efficient buildings.
Sand and gravel are not only non-renewable resources, their extraction also causes environmental damage. Specify crushed rock, or ‘secondary aggregate’, which is rubble from demolition, and can be used for infill, sub-bases and low-grade concrete.
Wherever possible, avoid the use of materials containing chlorine (eg. PVC compounds), lindane (known as hexachlorocyclohexane or HCH), Aldrin, PCP and TBTO (insecticide and fungicides used in timber preservation), mercury, cadmium, PCBs, PCTs, TCT, Organotin compounds and titanium dioxide. Consider alternative methods of timber preservation, such as those marketed by Hutton & Rostron Environmental Investigations Ltd. Certain ‘natural’ preservatives are available such as permithrin, boron compounds and acypetacs zinc. Use low-formaldehyde particle board in place of plywood or chipboard, and recycled paper insulation instead of oil-based or high-energy glass wool products.
Insist that all hardwoods are from sustainable sources; and use alternative materials wherever possible. In particular, avoid imported, ready-made hardwood doors, which are very unlikely to use material from sustainable forests. Plywood may contain hardwood; MDF, chipboard or particleboard do not. European hardwoods are all acceptable.
Avoid lead in paint and pipework. Reduce dependence on lead for flashings, and reduce the number of flashings wherever possible.
Avoid the use of CFCs & HCFCs (used as blowing agents for insulation materials) and Halon (used in fire extinguishers). HFCs are alternative and more environmentally-friendly gases. Polystyrene insulation does not involve the use of CFCs.
Encourage the re-use or recycling of packaging material and practise it in the workplace.
Avoid PVC, which cannot easily be recycled and uses toxic chlorine. PET is an alternative to PVC, and it can be recycled indefinitely. Specify plastics based on renewable sources instead of oil, such as formaldehyde, casein, cellulose, resins and gums, rubber, pitch or bitumen from asphalt lakes.
Carefully examine the site/existing building at the design stage, and aim to recycle materials wherever possible, eg. railings, roof timbers. Insist that reusable materials and components are removed from site and safely stored for future use.
Other materials which can be recycled include asphalt & bitumen, ‘secondary aggregate’ (demolition rubble), bricks, clay & ceramic floor tiles.
Specify WC cisterns with dual-flush for water-saving.
Questions for your suppliers:
1. Is the raw material renewable?
2. Is the process of obtaining the raw material environmentally destructive?
3. What is the true cost of the material? ie in what proportions is the energy used in manufacture, transport, installation and maintenance? In addition, what employment is sustained by its production?
4. How long will the product last?
5. Can it be recycled?
Alternative energy sources
Whenever possible, opt for renewable sources:
methane (from biomass or landfill)
wood (from sustainable forests)
wood (from non-sustainable forests)
Energy conservation: some guidelines
Specify the highest level of thermal insulation affordable.
Avoid cold bridging and interstitial condensation risks by careful detailing.
Always specify double glazing (or better), preferably with a low-emissivity pane (eg. Pilkington ‘Kappafloat’).
Consider lightweight block walling, particularly when made using recycled materials such as fly ash.
Avoid air conditioning. Adopt measures for natural cooling and encouragement of air movement, eg central mechanical ventilation (with heat recovery) or passive stack ventilation with trickle vents. Computer control of heating systems will increasingly improve efficiency.
Decentralise hot water supply with the use of instant heaters, if appropriate.
Specify low-energy light fittings. Reduce lighting level to 350 lux. Make better use of task lighting, daylight and lighting controls.
Consider the installation of heat recovery mechanisms and energy-efficient condensing boilers.
Arrange assessment by a specialist of the building envelope’s total energy consumption efficiency in terms of (consult EDAS for suitable experts).
Total energy consumption:
Different materials have different energy values (ie the amount of energy used in their manufacture) and vary in their recyclability and reusability. Aluminium rates very poorly as its manufacture demands a great deal of energy. Bricks, plasterboard and ceramic tiles also rate badly in this respect. Consider and use alternatives wherever possible.
The amount of energy used in erecting and assembling components also varies. Timber rates well while concrete scores badly.
This energy cost, which continues throughout a building’s lifetime, is the biggest of the three. Any additional capital cost which helps to keep in-use consumption low is therefore money well spent.
Long life, loose fit, low energy is the aim.
It is always preferable to reuse, extend or adapt an existing structure rather than demolish or rebuild.
Life cycle costing
Consider the life cycle cost of alternatives, to establish the wisdom of ‘green’ design.
Avoid internal noise by siting soil stacks and water services ducts away from living rooms or bedrooms. Ensure that adjacent rooms in adjoining dwellings are compatible: create buffer zones wherever possible, with storage along the party wall. Build in sound insulation to floors and/or ceilings between dwellings. Take care to avoid or fill direct air paths caused by holes or gaps. Insulate stud partitions wherever possible with absorbent quilt in the cavity. Consider cement-bonded chipboard for flooring.
Reduce external noise by tree & shrub screening, soft surfaces outside windows, double glazing with one pane at least 6mm thick, sound-reducing ventilators and good roof insulation.
Sick Building Syndrome
There are a number of preventative measures that will help to avoid this damaging syndrome in your building. Avoid air conditioning: buildings are best cooled by natural means. Take care not to use materials with toxic vapours, eg paints with chemical solvents (safer, vegetable oil- and water-based paints are available). Specify anti-static carpets.
The landscape around a building becomes a mini ecosystem. Planting trees helps renew natural resources as well as filtering the air and reducing noise. Avoid sycamores and limes, which drop sticky sap and instead use Acer Campestre (Field Maple) or Platanus Hybrida (London Plane) for street trees. Smaller native trees like Sorbus Aucuparia (rowan), Prunus Avium (wild cherry) and Malus spp. (crab apple) are suitable for gardens and good for wildlife. Encourage the establishment of wildlife habitats by aiming for low maintenance. Avoid the use of peat and specify shredded bark mulch instead. Choose chestnut pale fencing which uses the by-products of coppicing or opt for hedges in place of fences or railings.
Need to know more? Please call and we’ll be happy to help.