Sustainability of material selection should be done with life-cycle of the structure in mind. Just adhering to the sustainability concept might compromise other essentials for a feasible life-cycle of the building.
Buildings account for a significant portion of material and energy usage. The environmental qualities of materials, on the other hand, have not historically been a concern in design or construction.
Developed nations have set carbon-free emission targets for the future to counter rapid global warming. This vision will never be fulfilled without correcting malpractices in traditional industries.
Sustainable building material selection for green buildings is the timeliest approach in reducing carbon emissions through material usage.
Below are 8 factors to consider while selecting sustainable material that would ensure a functional building with essentials for a healthy building life-cycle.
- Functional requirement
Functional requirement is a major concern while selecting sustainable material. Each building is unique in its function and features. Its next to impossible to find two projects with identical conditions and functions. These functional requirements can be further classified into the following
| Physical properties | Porosity, water resistance, water absorption capacity |
| Mechanical properties | Elasticity, strength, Tensile stresses, Plasticity, Hardness, brittleness, ductility |
| Chemical properties | Acid and base resistance, corrosion resistance, efflorescence |
| Biological properties | Resist fungus and algae growth |
| Thermal properties | Thermal expansion, thermal conductivity |
| Electrical properties | Electrical conductivity, resistance |
| Acoustic properties | Contain sound waves, prevent sound conduction (soundproofing) |
For example, residential buildings should have the capability to house occupants for longer time periods, protect them from natural elements, thermal comfort, etc. Theaters must have the ability to contain sounds (Acoustic properties) and to control lighting conditions. Marine structures should resist salt water and be waterproof (Physical properties).
When choosing sustainable material these functional requirements must be considered in a way to avoid compromising them for the sake of sustainability. This ensures client is satisfied by the final product as well as sustainability is maintained.
- Economic (life cycle cost)
Economic factors are more impactful in selecting sustainable material for modern constructions. Economic sustainability of material demands a complete assessment of life-cycle cost of the material. This includes initial acquirement cost and operational cost as well.
Initial cost consists of the price, buildability, and implementation cost. Buildability implies the challenges related to using the material, wastage during construction, requirement of skilled workers, machinery required and material handling issues.
Operational cost incudes the requirement of maintenance and durability of the material to wear and tear. If the material has less durability and high maintenance, then its economically unfeasible in the long-term cot assessment.
- Appearance (Aesthetic features)
Aesthetical features mostly depend on the proper design. The architect must choose materials so that they properly blend with the fundamental theme of the building. If natural material like coconut husk is used in an office building interior, then it will seem out of place as they are more suitable for resorts type buildings.
Sustainable material selection done with aesthetical appearance is less complicated with the involvement of a talented architect.
Material for finishes must be selected for internal finishes should be done with their natural appearances in mind. If not, it becomes economically unfeasible to use processed material to change texture.
- Availability
A sustainable construction must use less virgin material to prevent pollution through material extraction. Construction materials are in demand the never before, which has led to a scarcity of material and mass extraction processes disregarding environmental impacts.
Plus, under Leeds green building rating system, use of locally available material fetches points. Because Materials and Resources credit category focuses on reducing embodied energy and other environmental consequences related with construction materials extraction, processing, transportation, maintenance, and disposal. The standards are intended to enable a life-cycle strategy that enhances performance while protecting virgin material.
The most sustainable method in material acquisition is to incorporate locally available material around the project. This reduces the demand for more pollutant material, reduces transportation and tax expenses, and mostly reduces the environmental impact.
For example, a hotel roofing can be done using locally manufactured clay tiles. This adds aesthetical element to the building while reducing the use of roofing sheets (asbestos) or metal sheets.
- Durability
As highlighted, durability and structural integrity doesn’t need to be sacrificed for the sake of sustainability of the material. There are plenty of new biodegradable polymers, composite material, and plant-based material that can sustainably replace concrete or polymers.
Durability of the material is a major concern with regard to building life-cycle. Less durable material such as cheap plastics will need replacements within short time intervals, which is less feasible and requires more maintenance.
When choosing a sustainable material, the durability of the material must be in par with other materials used in the building. Because some buildings are intended to last longer while some have no concern with the life span. If the flooring of an auditorium is not durable against the foot traffic, then the overall project is not feasible for the client.
- Maintainability
Maintainability entirely depends on the physical factors and aesthetical of the materials. Sustainable material must be as much as maintenance required as conventional materials or much less. This creates more traction towards replacement of conventional material with composite or sustainable material.
- Environmental impacts
Sustainable material is a better solution for resource depletion and avoiding the use new materials with emissive extraction processes.
Impacts to land during extraction is a major concern with material sustainability . Essential components of cement such as limestone (calcium carbonate) requires excavation processes using machinery. Plus, cement industry is a main contributor for carbon dioxide pollution.
Waste and pollution can be totally eliminated with the use of sustainable material such as bamboo, straw, steel etc. These materials are renewable and readily available with minimum impact on the environment upon extraction.
Impacts to biodiversity is a major concern when choosing sustainable material. Some materials should not be excessively extracted as they can be a part of the ecosystem in the region. Few options such as reed roofing is a feasible option as they grow fast and even wilted reeds can be used afterwards.
- Health and safety
Ultimately the material selection must adhere to health and safety guidelines imposed by rating systems and state laws. Regardless of sustainability and convenience, if the material is toxic or more harmful compared to conventional material, then it is not suitable for consideration.
Construction industry have had incidents with toxic material such as Lead in paints. Industry has corrected these issue by banning these types of material and imposing restrictions against use.
At the end of the day the material must be friendlier for the occupants. Attempts to account for health and safety of occupants are recognized by point systems and very high ranges are allocated.
Conclusion
Green building concept had drawn traction towards sustainable material selection for modern constructions.
This article has identified 8 factors to consider before selecting a sustainable material for your next project.
Strategies and standards for sustainable design are always growing and improving. New technologies are constantly being brought to the market, and current scientific research has an impact on building design techniques, which means plenty of materials choices that adhere to the factors above are available and are feasible for constructions.
Sources
Life cycle assessment (LCA) of sustainable building materials: an overview
G.K.C. Ding, in Eco-efficient Construction and Building Materials, 2014
(Guggemos and Horvath, 2005)