Debunking the 13 myths around sustainable construction
The building and construction sector is responsible globally for 36% of energy consumption, 38% of carbon emissions and 50% of resource consumption. This has to change. Using more sustainable materials, solutions, methods and processes are no longer a nice to have but critical to the sector having a sustainable future.
Which implies promoting and fostering sustainable construction. A construction approach that is both better for the planet, by lowering carbon emissions, reducing construction and demolition waste, and improving energy, resources and water efficiency, and better for the people, by creating healthier and more comfortable homes and safer jobsites, without compromising on the economic value and the quality of the construction
However, there are many misconceptions about sustainable construction projects. Let’s clear some of those up.
1. Sustainable construction means building with care for the environment TRUE BUT NOT ONLY
The construction sector generates a lot of carbon emissions, solid waste, pollutions and has a very high demand for energy and natural non-renewable resources. Sustainable construction is about mitigating and even reversing those harmful effects. This can be achieved by reducing the whole life carbon of buildings and making a more efficient use of natural resources, in particular through a more circular approach.
The building’s whole life carbon encompasses both the embodied carbon and the operational carbon. The embodied carbon refers to the greenhouse gas emissions arising from the manufacturing, transportation, installation, maintenance, and disposal of building materials and products. Operational carbon refers. to the total emissions from all energy sources used to keep our buildings warm, cool, ventilated, lighted and powered.
So being environmentally conscious is indeed part of sustainable construction but it is not the only part. Of course, it is about seeking for high level of energy efficiency, increased use of renewable energies, materials and solutions with reduced embodied carbon emissions, reduced use of non-renewable resources and reduced freshwater consumption, increased building’s lifetime and use rate and reduced amount of non-recovered construction & demolition waste.
But sustainable construction is also about taking care of people: by making jobsites healthier and safer for workers and indoor environments healthier and more comfortable for buildings’ occupants. And, on top of the two sustainability pillars (better for the environment / better for people) it is also about performance: a sustainable construction does not compromise on the economic value and the quality of the construction.
2. Sustainable construction is just another name for light construction FALSE
When we talk about light construction, we mean building methods which uses materials like steel, timber, engineered wood and concrete as the main load bearing elements to produce a framed structure. The materials are used either singularly or in combination (hybrid). Next to that, light construction involves usage of lighter wall, ceiling, façade, flooring and roof systems and assemblies.
Light construction is also more flexible and modular, and at the end of the life of the building, it is easier to dismantle and then reuse or recycle the materials.
For all these reasons, light construction methods are often used for sustainable construction projects.
Nevertheless, a sustainable construction is not necessarily a light construction. It can also consist of heavy and massive load bearing walls made of bricks or concrete. Such constructions are also reducing their carbon footprint and improving their efficient use of natural resources. Companies such as Chryso are contributing to develop new concrete formulations that contain 50% less CO2 than standard concrete.
3. A sustainable building prioritizes protection of the environment above the occupants' wellbeing FALSE
A sustainable building combines both a reduced environmental footprint with an enhanced health and wellbeing performance for both jobsites’ workers and buildings’ occupants. Reducing the whole life carbon of a building and increasing its resource efficiency cannot be done at the expense of the occupants. A sustainable building delivers improved indoor air quality, better acoustics, better thermal comfort and better visual comfort to its occupants.
4. Sustainable construction means creating or renovating low carbon buildings
TRUE BUT NOT ONLY
For sure, sustainable construction means creating or renovating low carbon buildings (or tending towards zero carbon buildings)
A low carbon building has significantly reduced whole life carbon carbon emissions. Whole Life-Cycle Carbon (WLC) emissions are the carbon emissions resulting from the materials, construction, and the use of a building over its entire life, including its demolition and disposal. A WLC assessment provides a true picture of a building’s carbon impact on the environment over its entire lifecycle. It combines both the embodied and the operational carbon emissions. Operational carbon emission can be reduced thanks to high level of energy efficiency (thanks to well-insulated building envelops) and the use of low carbon energies to operate the building, in particular renewable energies possibly produced on site. The selection of low carbon materials and solutions will contribute to reduce the embodied carbon part as much as possible.
But sustainable construction also means a lot more than going low carbon only. It is also about building and renovating with a more efficient use of natural resources, without generating non recovered waste, and with solutions that will enhances workers and buildings occupants’ health and wellbeing.
5. Building and renovating in a sustainable way means giving a preference to local and biosourcedmaterials
Things are never black or white when it comes to sustainability. Emissions from the transportation of building materials between the manufacturing plant and the jobsite contribute definitely to the carbon footprint of a building. Reducing the distance between the plant and the jobsite can be one way to reduce the carbon impact of transports. Building planners of the BedZED complex in south London were able to source its materials from within an average radius of 66.5 miles, 40 miles less than the national haulage distance. This saved 120 tons of CO2 and 2% of the project’s embodied CO2.
But this is not the only way to reduce the carbon impact of the transport: low carbon transportation modes can be selected such as trucks powered with biogas or waterway transport: this is the choice made for the Paris 2024 jobsite. And the packaging of materials can also help to reduce the impact of their transportation: for instance, a glasswool insulation product compressed by 1 to 10, thanks to its packaging will have a much lower impact than a non-compressible insulation material transported over a shorter distance…
In the same way, biosourced materials are not necessarily more sustainable than other materials. They may for instance contain hazardous substances (such as fire retardants or additives against mold). All manufactured products have a carbon footprint over their life cycle. It is not because a product is manufactured out of an energy intensive process that in the end it has necessarily a more important carbon footprint. It is important to escape prejudices and to rely on facts and figures. Very often the carbon footprint of glasswool insulation products is lower than the one of wood fiber insulation products.
On the other hand, mineral based products become more and more sustainable as their production processes become less energy and carbon intensive and their raw materials are replaced by secondary raw materials (recycled content and by products from other industries).
The best way to know and compare the carbon footprint (and more generally the environmental impacts) of different construction products is to look at their LCA (life cycle assessment) results (available in the EPDs, environmental product declarations). Comparison must be done carefully as explained in the recently in the recently published LCA & EPD guidelines.
6. Sustainable construction is about preserving/saving natural resources TRUE
One of the key pillars of sustainable construction is resources and circularity. This relates to reducing the use of non-renewable resources and freshwater and the generation of non-valorized waste over the entire lifecycle of the building. This could mean reducing the use of water-intensive materials like cement-based concrete and maximizing the ability of the occupants to collect rainwater and reduce leakage from pipes. It is also related to increased lifetime and use rate of the buildings and a drastic reduction of n the waste landfilled when the building is demolished, or, better, disassembled. Another way to reduce the use of water in a construction project is to employ metal or timber framing, as these techniques rely on prefabrication and require no wet trade processes on site. In the early 1990s BREEAM - which certifies the sustainability of buildings - set a requirement for new homes to have a six-liter flush volume for domestic toilets, one-third less than the industry standard at the time. But it is not just water. Sand is the most consumed resource after water and is a main ingredient in cement, but it is finite. Desert sand is not suitable in construction and so sustainable projects will aim to use as little as possible.
7. All construction, sustainable or not, always produces as much waste! FALSE
Buildings generate a lot of waste at the time of their construction and when they come to the end of their lifecycle. Construction and demolition waste account for about 40% of all solid waste streams.
It is estimated that the construction industry accounts for one third of the solid waste that ends up in landfill sites in the UK, roughly 77.4 million tons. China’s annual construction and demolition waste is somewhere between 1.55 and 2.4 billion tons, and account for 30% to 40% of urban waste. On top of the huge volumes of waste, another challenge is that most of these wastes are landfilled and not valorized.
However, this can be significantly reduced by designing and building in a more sustainable way. Solutions can be selected that will generate very limited amounts of waste on site and will allow for easy dismantling at their end of life so as to facilitate reuse or recycling; waste will be sorted at source to be easily reused or recycled, possibly in closed loop.
Building waste glass in the EU is almost never recycled but if it were, it could avoid 925,000 tons of waste going to landfill every year and reduce carbon emissions by 230,000 tons annually.
8. Sustainable construction means healthier materials... for those who install them on building sites, and for those who live with them afterwards
Sustainable construction takes care of people both workers on the jobsites and buildings occupants.
Building more sustainably means delivering solutions that reduce builders' exposure to hazardous substances during installation and improve their working conditions (lighter products, less dust, non-irritant products, no bad smell…). It does also mean delivering safer and more comfortable indoor environments for the occupants: improved indoor air quality, better acoustics, better thermal comfort and better visual comfort.
9. A sustainable building is a flexible, adaptable, multi-use, multi-purpose building
As it often takes less time and resources to repurpose a building than to erect a new one, a sustainably constructed building can be changed and redesigned to fit different use cases. This should be considered at the very start of the building’s lifecycle as it is being designed as adaptability can extend the lifecycle of the building. A flexible building does not need to be demolished as soon as a conventionally constructed building, delaying the carbon emissions associated with the construction of a new build.
10. A sustainable building means a building that can be easily demolished/dismantled/deconstructed?
It is important that sustainably constructed buildings leave as small a footprint as possible on the site and the environment when it comes to the end of its operational life. In relation to resources and circularity, a tenet of sustainable construction is that there is a reduced amount of non-recovered construction and demolition waste. Reusing or recycling materials and products is only economically possible if they can easily be separated and sorted on the deconstruction jobsite.
The building erected to house politicians during the Netherlands term of the Presidency of the Council of the EU was dismantled once the presidency ended. The bioplastic used to make it with 3D printing was recycled to be reused with future sustainable construction projects. Facades systems from Placo® like F4 or Placotherm INTEGRA are easier to dismantle and reuse than concrete or wall blocks and so can facilitate this repurposing.
11. Wouldn't sustainable building mean above all... renovating existing buildings?
TRUE AND FALSE
Globally, there will need to be 96,000 new affordable homes built every day to house the 3 billion people who will need access to a home by 2030. However, some regions do not have the space in which to erect new buildings and instead must renovate the existing housing stock or even repurposing commercial building stock.
Throughout Europe there are approximately 200 million buildings that were built before 2001 that will still be standing by 2050. Therefore, sustainable construction in places where land is scarce and existing building stock old and important will focus heavily on renovations.
Project Homekey in California involves the local authority Orange County purchasing and repurposing hotels, motels, vacant apartments, and other buildings. Similarly, the Egypt Housing Strategy is focused on opening up closed and vacant units. In these instances, if sustainable methods and materials were used, sustainable construction would involve renovation.
In India, however, the housing shortage is being addressed in a sustainable way by construction new houses with lightweight materials, quickly and at scale.
So depending on where you are in the world, sustainable construction equates to either building from scratch or renovating.
12. All sustainably designed and built constructions look the same because sustainable construction drives uniformity
Sustainably constructed buildings can be just as aesthetically pleasing or as striking as a conventionally built ones. This myth that all sustainable buildings look the same may have originated from perceptions about monotonous prefab houses from the 1950s. Examples of innovative sustainable renovations or new constructions include Mjøstårnet, the world’s tallest timber tower in Norway, the Echo building in the Netherlands, Ostro Passivhuas in Scotland and Casa Azul in Guarujá in Brazil. Distinctive sustainable construction doesn’t necessarily have to mean a construction from the ground up. Using lightweight and prefab products for parts of a building such as roofing, decking, siding, and trim can result in original features that are far from uniform. The Yale Science Building as well as Tampa International Airport were created with trim products from the CertainTeed range, resulting in impressive and unusual interiors. Eye-catching sustainable buildings are being used as multi-tenant residential buildings. EDEN in Singapore, an apartment building with balconies that resemble hanging gardens is one such building, so although all the apartments look the same, the building stands out against other tower blocks in the same vicinity. Similarly, The Wintles eco-community in the UK is a development of 12 timber-framed eco-homes with each property having its own visual character.
The Saint-Gobain Tower in Paris is another example of a unique iconic and highly sustainable building.
And let’s remind that in our approach to sustainable construction, esthetics is one of the key drivers under the quality pillar of the performance domain. Sustainability and performance go hand in hand for Saint-Gobain.
13. Sustainable construction or renovation is more expensive
TRUE AND FALSE
It is true that affordability is a concern for those wanting to acquire or occupy sustainably designed, constructed or renovatedbuildings. Four in 10 UK firms stated that affordability was the greatest challenge to adopting sustainable construction practices. In addition, studies have shown that higher upfont costs, as well as lack of education, awareness and incentives have slowed the move towards carbon neutral construction in Hong Kong and Singapore. So, there is the perception that sustainable construction is more costly. And while there is a slightly higher upfront cost, greener buildings cost less to operate than those that are conventionally built. According to the World Green Building Council, a newly built green building is 14% cheaper to operate over five years than a conventional one. In some cases, the greener option is the cheapest one. The designers of the BedZED project in south London used highly durable timber framed windows and found they were cheaper than PVC, reclaimed structural steel and timber were cheaper than buying new. Furthermore, recycled aggregate and sand are cheaper than virgin equivalents. Renovation reduces the operational cost of a building because additions such as double glazing can improve energy efficiency and reduce energy bills for the occupants. Insulation will have the same effect. Additions such as these can increase the value of the home and improve its energy rating. A 24-unit, 1980s residential block of flats in Prague, Czech Republic that was renovated increased in value by 27.5% and went from an energy class E to energy class B. When rented, sustainable offices prove to have higher occupancy rates, reduced occupants’ turnover and higher rents. The employees in sustainable buildings express a higher satisfaction at work and prove to be more productive. Students in sustainable schools will have an increased learning ability. Sustainable buildings tend to be sold with a premium price versus normal buildings and, at their end of life, their residual value in also generally higher.
That is why it is important to take a life cycle costing approach that consolidates all costs, savings and co-benefits over the entire life of the building.
The effects of global warming have been felt severely in 2022 via wildfires triggered by heatwaves and widespread flooding caused by glacial melting. The construction industry is doing its part to help reduce the level of global warming and mitigate these damaging consequences through the extensive use of sustainable construction materials and processes. However, public awareness of these techniques needs to grow and the fears and misconceptions about sustainable construction need to be allayed and dispelled. The answers are not always black and white. However, by explaining the nuances and laying out the indisputable certainties, demand for low-carbon and more circular solutions is sure to grow, at both the demand side from end consumers and the supply side from the architects and building designers.
Credits : Shutterstock/David Papazian ; Shutterstock/Kristin Spalder