Essential features for a successful and sustainable building:« Back to Construction Professional
One Planet Living
In the UK, we use three times more than our share of resources i.e. we are consuming three times more than the earth can provide. Not only will this practice not sustain us in the future but it is also an ethical issue. On 15 April 2007 we used up our share of the earth’s resources and started to use up others’ around the world.
‘If an activity is sustainable, it can continue to be carried out forever’.
The construction industry consumes resources in an unsustainable way and there are many actions we can take that will reduce and even minimise this consumption. A sustainable building is one that minimises consumption of energy, materials and water. By doing this, we can not only preserve these three fundamental commodities for future generations but we can contribute to minimising the effects of climate change.
Climate change is the biggest environmental problem we face today and we need to drastically cut back on our CO2 emissions by reducing fossil fuel use. Buildings use fossil fuel in three ways; below are some basic guidelines on how to achieve the reduction of CO2 emissions within those three groups (but this is by no means an exhaustive list).
- Energy: consumption both during construction (embodied energy – see Materials section below) and energy in use.
- Insulating the external envelope is one of the easiest and least expensive ways to reduce the fossil fuels used to service buildings throughout their life. Take care to detail the building so that there are no cold bridges and that the external envelope is airtight. ‘Build tight, ventilate right’ is a good principle to follow.
- Increasingly, there is also the issue of overheating in commercial buildings so always design the building so that it gains maximum passive solar energy where it is needed but is shaded from excessive solar gain where appropriate. It could be said that an air conditioned building is a poorly designed building.
- Design in as much natural daylight (with consideration for solar gain) to reduce the reliance on electric lighting and to improve the well-being of the occupants. Solar energy is free, carbon neutral and the supply is almost unlimited.
- Encourage clients to think beyond the capital costs – payback periods can be a useful argument when proposing environmental features. Also, take into consideration likely future scenarios: energy from solar panels becomes cheaper as fossil fuel costs increase, for example. Corporate clients can be persuaded to reduce energy consumption to contribute to their Corporate Social Responsibility
- Materials: as well as the embodied energy of building materials, using our natural resources has another environmental impact in that many of the products we specify for buildings are from a limited resource.
- Specify natural materials to minimise embodied energy, especially where the cost differential is small. For example, 95% of a painting and decorating budget is labour, so specify natural paints where possible to create healthy indoor environments and to avoid using petroleum based ingredients.
- Use locally sourced materials. Many of the building materials we use in the UK have come from abroad which increases the embodied energy of the material as it has to travel further, using fossil fuels to be transported.
- Design in on-site waste management systems from the start, giving them the best chance of surviving the challenges of the construction process. Significant savings for the contractor, which can be passed onto the client, can be made by pre-sorting site waste and having a management system such as SMARTwaste and WasteCostLite
- Design using the Waste Minimisation Hierarchy:
- First reduce the amount of materials used in the first place to minimise waste and maximise the efficient use of materials.
- Then consider whether the materials or elements of the building can be reused or reclaimed with little or no reprocessing. At the design stage, consider the whole life of the building through to reuse – is the design of the building flexible to allow for different uses? Can the building be demounted so that elements of the building can be reused? Visit the BioRegional Reclaimed website for further information.
- Then look at the possibilities for recycling materials and elements. It helps to specify materials that can be easily separated to make recycling more practical and that have are not highly processed – materials that are composite are inherently more difficult to recycle.
- Water: although there is a finite and reusable amount of water available for human use on the planet, once used, it takes a lot of energy to clean the water to make it suitable for human consumption again. It takes 1.2 kWh for every cubic metre of water cleaned to potable levels.
- Design in features that reduce water use at source before considering incorporating rainwater or greywater systems – this is a more effective way of reducing mains water consumption.
- Water saving devices such as dual flush (2.5/4 litres), low flush WC’s, aerated taps and low flow shower heads are simple substitutes for their conventional, more water consuming choices and do not require any changes to the design of buildings.
- Once all water reducing devices have been considered, using a rainwater harvesting system is a good way to minimise the environmental impact of water usage. Rainwater harvesting systems can collect water for use in flushing toilets, washing machines, plant irrigation, vehicle washing and cleaner’s sinks. For more information, please click here.
- Most greywater recycling systems use some kind of chemical treatment to keep bacteria from growing in the stored water. These chemicals add a further burden to the sewage treatment plants and should be avoided.
- As urban living throughout the world continues to grow, the materials that we choose for the external landscaping around our buildings affect how much rainwater can be returned to the ground on site. Impermeable surfaces such as tarmac increase surface water runoff and add to the burden on the sewage system whereas permeable paving or grass allow the rain that falls on site to percolate through the ground and replenish the local water table. As our climate changes and more rainfall is predicted in many parts of the world, it very important that we allow as much rainwater to either be collected and used within our buildings or allowed to go back to the ground. This is often referred to as SUDS (sustainable urban drainage systems).
Other important points to consider in the design and construction of a successful and sustainable building:
- Social and economic factors. A sustainable building is much more than an environmentally sound one – it must take into account environmental, social and economic issues. This includes aspects such as providing jobs for local people and considering the wider community when building – how the proposed building will affect local people.
- Introduce sustainable measures at the earliest possible stage of the project. The process of constructing a building is challenging and environmental features can fall by the wayside for various reasons. Try to make sure that the sustainable ideas are introduced as early as possible so that they have the best chance of surviving this rigorous process. Energy saving measures are particularly prone to this so early discussions between the architect and the services engineer will reduce this possibility. Also, try to discuss the scheme with the planners at pre-application stage to make sure that the proposals comply with current planning policy (local, regional and national) and that if there are unconventional features in the project, the planners will understand (and will therefore be more likely to endorse) the reasons for the approach you are taking.
- Consultants approach the project as a team. A collaborative approach to a project will maximise the chances of a successful outcome for a sustainable project and will be more enjoyable for the whole team. Working together allows all parties to contribute to the best of their abilities and the result is a project that everyone can be proud of. This requires good communication throughout the building process and a non-adversarial approach to the job.
- Monitoring of carbon impact. If there are targets for minimising the carbon that the building is responsible for, make sure that this is monitored during the design process if at all possible. Remember that a true low or zero carbon building takes into account the energy required to construct (and demolish an existing building where applicable) not just the energy consumed in use.
- On site interaction. Many of the best laid plans are not realised due to the procurement processes used in today’s construction industry. A process where the architects and other consultants are not involved with site inspections means that may not be a system for quality checking the construction and issues like airtightness will not be rigorously monitored. If this is the case in the project you are working on, try to ensure that the wording in the specification is a tight as possible and that there are no areas where an interpretation would lead to an unsustainable choice.
- Post Occupancy monitoring. In the past 10-15 years there have been many sustainable building projects with good intentions that have not been realised once operational. This can be for a number of reasons including (amongst others):
- misunderstanding of the architect’s drawings on site
- inappropriate installations of renewable energy technologies
- inadequate communication of how the building is intended to be operated
- the occupant’s habits
Gathering Post Occupancy Data (POD) will allow unachieved targets to be monitored and recorded and, if this information is shared, these shortfalls not to be repeated.
- Do what works. With accurate information such as POD (see above), we can make sure that the money spent on buildings is used in the most effective way, getting the most ‘bang for your buck’. Some measures, such as a well insulated, airtight external envelope may not seem an attractive proposition for a client who wants to advertise their commitment to sustainable building but making the building fabric work to minimise the carbon impact is in fact one of the most effective ways of reducing the environmental impact of the building. Doing what works not what looks good is best is a good principle to work to.
- Biodiversity. The planet has lost approximately 20% of all species and 50% primary of forests in the last 100 years – this is clearly not a sustainable way of living within our ecosystem. In order to live in a world with abundant biodiversity, we need to respect the flora and fauna that surround us and not consider them a simply resources to exploit. Legislation such as The Code for Sustainable Homes (and its predecessor, EcoHomes) includes biodiversity as an important aspect of sustainable building.
Healthy buildings. When pollution is discussed, it is often referring to the pollution arising from traffic or industrial processes but in fact, the indoor environment can be up to ten times more polluted than the external one. This is due to a number of factors including poor internal air quality and the choices of materials we make to finish the building interior with. We spend 80-90% of our lives indoors and so it is vital that we create healthy interiors that promote well being rather than being detrimental to our health. Considerations such as ventilation, paints and finishes, floor coverings and other, less measurable factors such as colour choices, views and furnishing can all help to make the internal environment one that promotes good health.