The 9 Principles of Sustainable Architecture

In this article, we focus on defining in detail one of the most important attributes of architecture that must guide the sector’s path in the coming years: architectural sustainability.

In architecture, sustainability must be approached from a global perspective that includes all phases of the building construction and use process, as well as each of the resources that compose and maintain it in operation, whether directly or indirectly.

Thus, the first concept we must address when discussing sustainable architecture is the assessment of the building’s complete life cycle, from the production of the raw materials that compose it, through their transport and transformation, construction, service life, and eventual dismantling.

WHAT IS A BUILDING’S LIFE CYCLE?

In architecture, LCA—Life Cycle Assessment—refers to the set of techniques that determine the environmental impacts associated with a building from the moment it is conceived until the end of its service life.

The LCA considers each stage so that the processes or products generating the greatest impact on the environment or people can be identified, thus considering regulation or improvement options with the objective of reducing a building’s ecological footprint.

The LCA environmental assessment methodology is regulated by the International Environmental Management Standard ISO 14040, in force since 2006. [1]

ISO 14040 defines 6 phases that constitute a building’s life cycle:

1. Extraction

The first stage of a building’s life cycle is characterized by the extraction and processing of raw materials from the natural environment, equally including the energy input necessary to carry out this activity.

2. Manufacturing

The raw material undergoes a production process through which it acquires the form of the desired product.

3. Transport

The components are transported and distributed to the construction site. This requires transport infrastructure adapted to both the product size and the distance between the production center and the construction site entrance.

4. Construction

Construction refers to the set of construction processes implemented for the materialization of the building. This stage is considered complete once the building is ready to be used.

5. Service Life

The service life of buildings takes into account the duration and use of the building from the moment occupation begins until it no longer functions adequately or can no longer be used for the function for which it was conceived without the possibility of adaptation or transformation. This interval includes its use, maintenance, and possible repairs.

6. Dismantling

Once the end of its service life is reached, the building becomes a set of waste to be disposed of.

Dismantling should ideally be carried out, following circular economy principles, in such a way that each of the elements composing it can be reused, recycled, or returned to the earth, thus closing the life cycle.

CIRCULAR ECONOMY

As we have seen, the assessment of a building’s life cycle is closely linked to the concept of circular economy.

The depletion of primary resources, climate change, and the loss of planetary biodiversity are some of the direct consequences of the current linear economic system. This is a conception based on producing, using, and discarding, without considering the environmental consequences generated by the production of materials intended to be used and discarded as waste at the end of their service life, without acknowledging that these are limited resources.

As a response to this inefficient management of resources and waste, the circular economy emerges.

The circular economy is a restorative system that contributes to climate neutrality. It is based on 3 core concepts: durability, repairability, and separability, so that a product can remain in circulation for as long as possible.

In this way, the conventional linear structure based on the sequence of extract, manufacture, use, and discard becomes a closed cycle of manufacture, use, recover, use.

Applied to construction, the circular economy is based on the cyclical use of resources, the use of recoverable, reusable, recycled, or recyclable materials, and simpler construction methods that require zero or near-zero energy consumption. [2]

SUSTAINABILITY AND THE IMPACT OF ARCHITECTURE

Applied to the field of architecture, sustainability takes on different scales: the territorial scale, the urban scale, and the built environment.

Sustainability in Territorial Planning

In a period of environmental crisis, territorial planning systems have introduced criteria and determinations that lead us toward more sustainable territorial development, toward a model more respectful of people’s lives and ecosystems. Therefore, sustainable territorial development has become, in recent years, one of the main guiding principles of territorial plans at the European scale. [3]

The link between sustainable development and territorial planning emerges as a response to the need to curb the negative environmental consequences of economic growth in today’s globalized world. It is understood as the territory’s capacity to develop in accordance with the environmental characteristics of the environment where land use changes are proposed, including not only physical environment issues but also socioeconomic and cultural aspects. [4]

Urban Sustainability

We understand the urban environment as the result of human intervention in the physical environment. It is the set of public or private services, facilities, and infrastructure that make up the urban fabric.

When we speak of urban sustainability, we refer to the pursuit of developing an urban environment that does not degrade the urban setting—that is, that generates the least impact on it and balances environmental, social, and ecological needs.

Protecting the natural landscape, preserving built heritage, promoting the quality of public spaces, reducing water and energy consumption, minimizing the impact of construction materials, and/or reducing generated waste are, among others, some of the criteria established to regulate and ensure urban sustainability. [5]

Designing Sustainable Urban Environments: Permaculture

Permaculture is presented as a series of principles that respect and integrate into the natural ecosystem. Also known as “permanent agriculture,” it is based on designing sustainable urban environments aimed at creating self-sufficient, ecologically sustainable, economically viable systems that do not exploit or pollute.

To implement these ideas, 3 basic ethical principles are established: care for the Earth, care for people, and fair distribution of surplus.

Sustainability of the Built Environment

The last scale of sustainability in architecture is the built environment, which encompasses all building typologies: industrial, services, offices, residential, leisure, etc.

In recent years, due to the need to measure the impact of goods and services that society generates, the Life Cycle Assessment (LCA) methodology has been developed. When applied to the built environment, it evaluates the positive and negative impacts on the environment and people of a building.

The life cycle begins during a building’s conception, passing through the entire production process of the raw materials that compose it, the construction process itself, use and maintenance, and dismantling or renovation at the end of its service life.

In each of these phases, an impact of greater or lesser consequence is generated on the planetary environment and on living beings. For this reason, sustainable architecture is closely linked to the concept of zero impact.

Zero impact is the way of expressing that a building’s impact on the environment in which it is located is sustainable, so that despite having implemented a construction in an undeveloped natural environment, its impact on it respects its initial conditions, making responsible use of the land, integrating into the landscape and environment, and without altering the quality of the ecosystems that compose it.

This impact is measured at a local scale, at the location where the building is situated, but also at a global scale, considering impacts that are counted in the total damage to the environment, such as the effect on raw materials or non-renewable planetary resources, greenhouse gas (GHG) emissions, or alteration of the natural water cycle and consumption of water resources, among others.

The Sustainability of a Building in Relation to Its Impact on the Environment and People

The complete list of impacts of a built environment has recently been cataloged in the European Union’s LEVEL(s) framework, a voluntary application methodology aimed at preparing future building impact regulation directives on the continent.

Additionally, there are numerous private building certifications developed by independent companies or institutions that also follow different methods of assessing a building’s impact.

The most relevant impacts of the built environment are:

1. Land Use

In climate terms, ‘land use’ refers to the utilization of the surface of all urbanized and vacant land, on which buildings have a significant impact through their transformation of the landscape, use of natural resources, and emission of pollutants and waste into their environment.

2. Biodiversity

Biodiversity is defined as the interaction between human beings, fauna, and flora; soil, water, air, climate, and landscape; and material goods and cultural heritage. Reconciling the future preservation of biodiversity with human progress according to sustainability criteria is essential.

3. Water Resource Management

The focus is usually placed on water use during a building’s service life, overlooking its use in construction and material manufacturing. The path toward sustainable water management involves using water without depleting it, returning it to the environment with the same or better quality than when it was extracted.

4. Pollution and Waste

Pollution is a form of contamination at the urban scale caused by the release of harmful substances, in which most industrial buildings are involved, affecting the environment and the health of the population. Additionally, one of the main impacts of a building throughout its life cycle is the generation of waste during its demolition.

5. Greenhouse Gas Emissions

A building’s greenhouse gas emissions derive primarily from the life cycle of its materials, energy demand, and transport. Thus, the different types of carbon emissions refer to different phases of the building’s life cycle: embodied carbon, upfront carbon, and operational carbon.

6. Indoor Environmental Quality

The health of a building’s indoor environment is determined by 4 factors: air, temperature, humidity, and electroclimate. By applying available bioclimatic knowledge to construction, it is possible to create a healthy and pleasant indoor environment, with continuous air renewal being essential.

7. Health and Well-being

When we speak of sustainable architecture, we refer not only to the health of the planet but also to that of users. Buildings have the power to impact the physical and mental health of their occupants.

Air and water quality, humidity, dust, thermal, acoustic, and lighting comfort are some of the factors that influence people’s health levels.

It is important to prioritize the use of natural materials and avoid products containing toxins that emit harmful substances into the indoor air of inhabited spaces.

Buildings considered healthy have been designed according to biophilic design criteria, influence the emotional and psychological quality of people, and contribute to the creation of common spaces for socialization and human interaction, beneficial to the daily lives of their users.

THE 9 PRINCIPLES OF SUSTAINABLE ARCHITECTURE

1. Responsible Land Use

Land is the foundation of every architectural project, so integrating knowledge that prioritizes responsible land use into the design process is key to developing sustainable architecture.

Land is a finite and non-renewable resource; therefore, sustainable architecture’s first premise is to minimize its exploitation and artificialization as much as possible.

It is essential to conserve and protect the natural state of the land on which we build, not excavate excessively, maintain natural biodiversity, and allow natural flows. It is about achieving balance between occupied space and built space.

2. Integrated into the Environment

Sustainable architecture must not alter the landscape in which it is situated, creating harmonious spaces that protect the environment.

Buildings are the intermediaries between human beings and the spaces we inhabit.

Thus, it is essential that the building be situated and transform the environment in a respectful manner to promote a positive effect on the building’s life cycle and biodiversity.

Some strategies to achieve this include the integration of green roofs, the creation of water runoff systems that maintain the natural course, natural filtration of rainwater into the ground, and the planting of local vegetation.

The form, materials, and colors of the envelope are also key elements that will define the building’s integration into the landscape. Some urban regulations expressly define the envelope’s aesthetics to achieve aesthetically harmonious urban environments.

3. Bioclimatic Design

Building a bioclimatic building means designing so that the architecture is closely linked to the climate of the location where it is situated. It involves making the most of available natural resources.

There are different factors to consider, which vary according to the cold and warm seasons of the year, winter or summer:

To maximize winter performance, we create south-facing openings that allow us to capture sunlight and solar heat. The captured heat can be stored in dense walls and floors with high thermal inertia, and we will prevent it from escaping during the night thanks to high exterior wall insulation and envelope airtightness.

To optimize summer performance, we will protect south-facing openings with vegetated pergolas, porches, and overhangs that, by not allowing sun entry, will keep the thermal mass walls cool—a coolness that will be maintained throughout the day thanks to high exterior insulation. During the night or early morning hours, when the exterior temperature is lower than the interior, we will create north-south cross ventilation that contributes to cooling the house naturally. Additionally, we will avoid over-paving exterior spaces, which will allow the natural ground to absorb moisture naturally and contribute to reducing thermal sensation through evaporation during hot hours.

4. Self-sufficient Design

A self-sufficient building is capable of producing the energy and resources it consumes, supplying itself with zero or near-zero consumption.

Through bioclimatic design, the energy needed for the building’s operation is reduced, so that the energy that needs to be generated to meet the building’s needs can be produced using resources generated on the same land.

Self-sufficiency stems from a change in mindset based on responsible resource consumption: renewable energy generation, food self-production, and waste self-management.

5. Construction with Renewable or Biodegradable Resources

The choice of materials and construction systems plays a key role in measuring a building’s sustainability.

Building with renewable or biodegradable resources minimizes negative impact on the environment while reducing the amount of waste. The premise is to choose untreated natural materials, locally sourced (km 0), renewable, recyclable, and reusable.

Building with appropriate materials and methods will provide the home with additional health benefits and harmony with the environment. Materials such as raw earth, clay, wood, bamboo, or stone meet strict criteria for ecology, health, and sustainability.

6. Zero Ecological Footprint

The ecological footprint measures the environmental impact generated by human demand for resources. It assesses the Earth’s capacity to generate a particular good or service based on the area of productive land or water along with the volume of air necessary to produce it.

In architecture, the ecological footprint corresponds approximately to 90% from the production of materials necessary for construction and 10% from the building’s use phase.

To attempt to achieve a zero ecological footprint in accordance with sustainable architecture principles, it is necessary to use natural materials with zero CO₂ emissions, both in those used during the building’s construction process and in subsequent maintenance.

7. Free of Toxins and Pollutants

To contribute to the design of healthy and resilient spaces, it is necessary to use materials free of toxins and pollutants.

These are materials of natural origin, minimally processed, that do not incorporate toxins or polluting substances in their production and that are harmless to people and the environment.

These materials usually coincide with materials from the biosphere, and it is important to distinguish between renewable and sustainable materials whose consumption is balanced with the renewal of the raw material that composes them, and non-renewable or unsustainable materials whose extraction generates a sustained impact over time or whose demand exceeds their renewal capacity.

8. Circular Economy

The circularity of a building’s life cycle is one of the key concepts of sustainable architecture.

The sustainable production system operates according to the circular economy model based on continuous and regenerative cycles. It is essential that the materials composing the building can be recovered, recycled, or returned to the earth at the end of their service life.

To achieve this goal and avoid poor waste management, strategies for changing or adapting building uses are implemented with programs adapted to users’ changing needs, as well as dry construction techniques that allow materials to be recovered at the end of their service life for reuse or recycling.

9. Community and Interaction Among People

Living beings are interrelated with the space around us and, therefore, we must assume collective environmental responsibility that responds to the climate emergency, thus improving the quality of the space we inhabit.

Climate awareness that positions us as part of a global ecosystem with which we are interconnected and on which we depend is the foundation for promoting actions that lead to sustainability.

In architecture, generating sustainable built environments often depends on achieving sustainable communities in which people support and collaborate to achieve a common good, living in harmony with the environment.

Achieving sustainable urban environments depends on collaboration among businesses, individuals, and administration, generating strategies that allow us to create sustainable communities and cities.