20+ Sustainable Building Materials in 2023—Natural, Recycled, and More

Story at a glance:

• Architects and designers are increasingly turning to a large list of sustainable building materials for projects.
• Sustainable building materials typically have low embodied carbon or incorporate recycled waste products.
• Bamboo, cork, adobe brick, stone, reclaimed wood, and concrete alternatives are some popular materials.

The construction and use of built structures produces roughly 40% of the world’s carbon emissions, according to a 2019 report from the International Energy Agency. The construction industry as a whole is responsible for producing 25% of the world’s solid waste and extracting more than 30% of the planet’s natural resources. This is largely due to the types of building materials traditionally used in modern architecture—many of which require significant energy to harvest, prepare, and manufacture.

These figures can be mitigated by the widespread adoption of sustainable building products. Here are 21 of the most promising sustainable building materials in 2023.

What Makes a Material Sustainable?

Before we explore the different types of sustainable materials, let’s take a moment to discuss what makes a material sustainable in the first place, especially considering that “sustainability” has become a bit of a buzzword.

In the realm of green architecture, construction, and design, sustainable materials are generally considered to be those materials whose collection, refinement, production, and long-term use has minimal negative impact on the environment. Most sustainable materials are derived from—or are wholly—natural, renewable resources such as stone, bamboo, adobe, and the like, but the category can also include recycled materials like plastic.

Types of Sustainable Materials

1. Stone

Stone is one of the oldest building materials known to man. Readily available and constantly being produced by the earth, stone has a naturally low embodied energy, an extremely long life cycle, and releases no volatile organic compounds into the air, making it one of the most sustainable materials there is—especially if sourced locally.

Thanks to the sheer variety of stone types (e.g. granite, sandstone, marble, basalt, gneiss, quartz) and the wide assortment of stone products—raw stone, cut stone, stone slabs, stone panels, etc.—stone has a nigh-unparalleled range of construction uses.

Polycor, one of leading producers of high-quality stone in North America, has supplied stone for everything from floors and countertops to wall cladding and columns.

Pros of Stone

• Extremely durable. Stone is an incredibly strong material and many types of stone have high load-bearing capabilities; stone is also quite resilient and is able to withstand the elements with ease.
• Low maintenance. Once installed, stone products typically require very little maintenance—in most cases, periodic cleaning with soap and water and occasional grout/mortar touch-ups are all that’s required.
• Versatility. As previously hinted at, the sheer variety of stone types and stone products makes stone an incredibly versatile material, one that can compliment a variety of architectural styles and functions.

Cons of Stone

• Expensive. Compared to many other natural building materials, stone can be extremely costly, especially if your project requires a high-quality stone like marble or certain granites.
• Heavy. Similar to something like precast concrete, stone is an incredibly heavy material, which makes it difficult to transport and install—this can also have the unintended consequence of increasing construction time and emissions.
• Requires skilled workers. When it comes to stonemasonry, there is little room for error, as stone can be very difficult to move or alter once set in place; as a result, stone always requires skilled, experienced workers.

2. Reclaimed Wood

Wood is another building material that has been used for millennia—and while timber is technically a renewable resource, it can take a long time to regrow, especially if harvested unethically. That’s why utilizing reclaimed wood in new construction projects has become common practice.

“Reclaimed wood reduces the demand for harvesting new timber and minimizes deforestation. Proper forest stewardship is essential to ensure trees grow for years to come,” Kevin Fults, an expert in the wood industry, previously wrote for gb&d.

In most cases reclaimed wood can be used exactly as you’d use new wood, giving it a variety of applications, such as: building frameworks, flooring, furniture, walls, rafters, fences, etc.

If the reclaimed wood you’re using in your project has been certified by the Forest Stewardship Council, it can go toward earning LEED points.

Pros of Reclaimed Wood

• Reduces waste. According to data gathered by the EPA, wood accounts for roughly 8.3% of all landfill waste, despite the fact that much of it is still viable for construction purposes—incorporating reclaimed wood into a project helps minimize waste and extends the wood’s operational lifespan.
• Aesthetically pleasing. Due to the weathered, aged look of reclaimed wood, construction projects that implement it are lent a certain character that you don’t immediately get from fresh timber.
• Natural insulator. Regardless of whether it’s new or reclaimed, wood is a natural insulator with a low thermal conductivity, which means it will help keep interiors warm even in cold climates, thereby reducing a structure’s electric heating loads.

Cons of Reclaimed Wood

• Can be expensive. If you aren’t collecting recycled wood yourself, sourcing it from a company can be expensive—sometimes even more expensive than buying new wood—as reclaimed wood must be processed and inspected before it is ready for reuse.
• May contain chemicals. If the history of your reclaimed wood is unknown, it’s possible that it may contain unwanted chemicals that could damage occupant health in the long-term.
• Susceptible to pests. Similarly, reclaimed wood can contain hidden pests like termites and woodlice that can compromise its structural integrity—and even if it hasn’t been damaged by insects, reclaimed wood is still susceptible to future attacks.

3. Adobe Brick

Like stone and timber, adobe brick is another sustainable building material that has been used for centuries, particularly in the American southwest, Central America, and South America. As a composite material, traditional adobe is composed primarily of sand, clay, and silt that has then been mixed with water and some sort of organic material—such as dung or straw—that acts as a binding agent.

This mixture is then pressed into a wooden frame to create bricks. Once dried, adobe bricks are exceptionally strong and may be stacked like conventional bricks to construct load-bearing walls or laid out in rows to form flat surfaces, such as roofs.

After adobe bricks have been put in place, they are covered with plaster, stucco, or whitewash to protect them from the elements.

Due to the fact that adobe bricks are produced using local, non-toxic materials, produce little-to-no carbon emissions, and last for a long time, they are considered to be extremely sustainable.

Pros of Adobe Brick

• Energy-efficient. Adobe brick has a high thermal mass and low thermal conductivity, making it extremely effective at regulating indoor temperatures without the need for heating and air conditioning; as a result, adobe brick buildings are considered to be energy-efficient.
• Durable. Like most earthen materials, adobe brick is extremely durable and boasts a high compressive strength; when properly maintained, adobe bricks can last for thousands of years.
• Fire-resistant. Due to the fact that adobe bricks are composed primarily of earthen materials, they are naturally fire resistant and are capable of withstanding wildfires with minimal damage.

Cons of Adobe Brick

• Heavy. Due to their composition, adobe bricks are quite heavy—this can slow down construction and typically necessitates the installation of concrete foundation or footings, which can add to a structure’s overall carbon footprint.
• Not suitable for all climates. Generally speaking, adobe brick is best suited to very warm regions that receive little rainfall, as regular exposure to water or freezing temperatures can lead to accelerated deterioration.
• High-maintenance. In order for adobe bricks to retain their structural integrity, they must be inspected regularly so that any signs of damage (holes, cracks, etc.) can be addressed immediately; adobe bricks also require that you reapplying their coating every few years.

4. Earth Bags

For the most part, earth bags are exactly what they sound like: bags that have been filled with earth. If you want to get more specific, earth bags typically feature a plastic bag or sack that is then filled with a mixture of local soil. This mixture generally contains moist subsoil with a sufficient clay content, as clay helps the sediment remain cohesive—in some cases, crushed volcanic rock or gravel may be used.

For construction purposes, earth bags are laid out and stacked in staggered courses, similar to how brick walls are built. They are capable of supporting straight or curved walls and, in the case of the latter, often feature domed roofs. Once earth bag walls have been erected, they are finished with a plaster—this helps them better withstand the elements.

From a sustainability standpoint, earth bags are extremely environmentally friendly, as they require very little energy to produce, last a very long time, and can be recycled once they reach the end of their life-cycle.

Pros of Earth Bags

• Inexpensive. Due to the fact that earth bags typically make use of locally-sourced sediment, they are extremely cost-effective; this makes earth-bag construction a viable building strategy even in impoverished and low-income areas.
• Durable. As long as earth bags are properly installed and maintained, they are capable of withstanding everything from severe weather to earthquakes with ease; in terms of their actual lifespan, earth-bag buildings can stand for hundreds of years.
• Low-emission. Earth-bag construction requires very little energy expenditure compared to other construction methods, resulting in fewer carbon emissions

Cons of Earth Bags

• Labor-intensive. When it comes to both their production and construction, earth bags require a lot of manpower, as they necessitate the collection, transportation, and placement of hundreds (if not thousands) of pounds of sediment.
• Limited construction use. While earth bags have a variety of uses in small-scale construction projects, they are significantly less feasible for larger, more-involved building projects.
• Aren’t suitable for all climates. Earth-bag structures can handle a lot of abuse, but they don’t fare well in extremely wet climates, as prolonged dampness can cause the bags to expand and contract, resulting in structural deterioration.

5. Bamboo

Over the last few years bamboo has seen an explosion in popularity—a phenomena largely attributable to bamboo’s contemporary aesthetic and extremely fast growth rate. Unlike most hardwoods, which typically require twenty years between planting and harvesting, bamboo can be harvested every five to seven years. Bamboo also absorbs twice the amount of carbon, requires less water, and doesn’t need fertilizer to grow.

Traditional bamboo construction produces very little waste and utilizes the whole bamboo pole, split poles, and finely-worked bamboo slats to build everything from bridges and huts to the structural support systems of buildings. The Arc, designed by IBUKU for the Green School in Bali, Indonesia, is testament to how bamboo can be used to build the majority of a structure.

Bamboo can also be formed into planks using one of two methods: cutting poles into thin strips, drying them, gluing them together, and laminating the finished project or by shredding bamboo culms down into fibrous strands and weaving them back together to create stranded bamboo planks.

Laminated bamboo has a variety of construction uses ranging from fences and flooring to furniture and interior decorations. Due to its improved strength and durability, stranded bamboo is used almost exclusively for flooring.

Pros of Bamboo

• High strength-to-weight ratio. While it may not be as strong as steel, bamboo nevertheless has a high strength-to-weight ratio, which means it can safely support a range of complex structures.
• Joint mobility. Compared to most other building materials, bamboo joints have a higher range of mobility—this quality, along with its lightness, makes bamboo a great building material for earthquake-prone regions.
• Biodegradable. Once the construction life-cycle of bamboo is complete, it can be left to biodegrade and may be used for composting purposes in as little as six months.

Cons of Bamboo

• Moisture damage. Bamboo is only durable when it’s dry—if regularly exposed to water, it can develop fungal rot and deteriorate in just a year’s time.
• Attracts pests. Like hardwood, untreated bamboo is susceptible to attacks from termites and beetles, which can reduce bamboo’s lifespan by a significant margin; in order to deter pests, bamboo must be treated with boron.
• Shipping distance. Due to the fact that bamboo doesn’t grow as well outside of Asia and South America, it must be shipped long distances, which can result in increased carbon emissions.

6. Cork

Unlike timber, bamboo, or even hemp products, cork products do not require that the entire plant be harvested—rather, the bark is all that’s collected and doing so doesn’t harm the tree itself. This means that a single cork oak tree can be harvested multiple times throughout its natural lifespan, typically at intervals of once every nine years.

After it is harvested, cork is shredded, compressed into sheets, and baked in a kiln—the finished product is then cut into planks, tiles, or left as a sheet, at which point it can be used for construction purposes, typically as either flooring or insulation.

Once cork products reach the end of their construction-use cycle, they can be composted back into the earth.

Pros of Cork

• High insulating capacity. The cells of cork bark contain small pockets of air that effectively prevent heat from getting through, making it an excellent insulator.
• Antimicrobial. Due to the fact that it contains phenolic compounds, cork is naturally antimicrobial and is highly resistant to fungus, mold, and mildew growth.
• Fire resistant. In its natural state, cork is extremely fire resistant—it will burn, but it does so very slowly and without a flame, which reduces the pace at which fire spreads.

Cons of Cork

• Susceptible to UV damage. When used as flooring, cork has a tendency to yellow and fade over time if regularly exposed to sunlight.
• Can be expensive. Generally speaking, cork is more expensive than, say, laminate flooring, largely due to the higher level of skill required to harvest cork without killing the tree, as well as the fact that cork is only harvested once a year.
• Highly responsive to humidity. Unlike hardwood, cork expands in all directions when exposed to high humidity, which means it requires more room for movement; when humidity is low, it can cause gaps to appear in cork flooring, especially if it isn’t glued down.

7. Hempcrete

An alternative to concrete, hempcrete is a composite material formed by mixing hemp hurds with lime, pozzolans, or sand. As is the case with any crop, hemp absorbs carbon while it grows and continues to store carbon after it has been processed into hempcrete, thereby reducing its overall carbon footprint and making it much more environmentally-friendly than conventional concrete.

Due to its high thermal mass and lightweight nature, hempcrete is typically used as both an insulator and to form non-load-bearing infill walls—it can also be applied to existing walls as a plaster.

Pros of Hempcrete

• Renewable. Hemp is a renewable material with a very rapid growth cycle—once planted, hemp stalks can be harvested in just three to four months, making it more sustainable than hardwood, softwood, and even bamboo.
• Mold-resistant. Thanks to the inclusion of lime in the initial production process, hempcrete is both antimicrobial and antifungal, making it resistant to mold and mildew, which helps to improve indoor air quality.
• Moisture control. Hempcrete is capable of absorbing extreme amounts of moisture without jeopardizing its structural integrity or insulative properties, making it an excellent choice in areas with high humidity.

Cons of Hempcrete

• Long drying time. Once cast, hempcrete typically requires between 6 and 8 weeks before it fully dries and can hold a proper finish, thereby extending the overall construction time by a considerable margin.
• Low compressive strength. Unlike traditional concrete, hempcrete has a fairly low compressive strength, which means it cannot be used to construct load-bearing walls.
• Learning curve/limited experts. Due to the fact that hempcrete is a fairly recent invention, it isn’t particularly well-known within most construction spheres—as a result, it can be hard to find a company or contractor with the experience necessary to build with hempcrete.

8. Timbercrete

Similar to hempcrete, Timbercrete is another alternative to traditional concrete and is formed by combining sawdust and small wood chips with water, concrete, and binding agents. It is lighter and produces fewer carbon emissions than concrete, while also offering improved insulative properties.

In its current form Timbercrete is best suited for use in exterior walls that prioritize insulation over load-bearing capacity, though it can also be used in roofing due to it being lighter than concrete.

Similar to concrete, Timbercrete can be molded on-site or precast ahead of time and shipped to the project site.

Pros of Timbercrete

• Ready availability. Due to the fact that both concrete and sawdust/wood chips are readily available in most places, Timbercrete can be sourced locally, thus reducing construction time, costs, and emissions.
• High thermal capacity. Timbercrete is capable of absorbing and storing thermal heat during the day and releasing it slowly throughout the night; this helps improve a structure’s overall energy efficiency.
• Traps carbon. Unlike conventional concrete and many other traditional building materials, timbercrete actually traps carbon and keeps it from entering the atmosphere.

Cons of Timbercrete

• Low load-bearing capacity. Compared to concrete, Timbercrete has a much lower load-bearing capacity, which means it can’t be used for structural support.
• Requires precise mixing. In order for Timbercrete to be structurally sound it needs to be mixed correctly. Considering that Timbercrete is a relatively new material, there aren’t many guides detailing the precise mixing process.
• Limited uses. Due to being weaker than concrete, timbercrete has fewer practical uses and is mainly confined to non-structural walls, fences, and small exterior structures.

9. Sheep’s Wool

Unlike most of the other materials on this list, wool isn’t prized for its durability, strength, or versatility, but for its insulative qualities. As a natural insulator, wool is an excellent alternative to conventional fiberglass insulation—it doesn’t contain any dangerous substances, effectively regulates temperature, is flame resistant, and even helps remove toxins from the air.

Wool has also been used as a sustainable alternative to synthetic-fiber carpets, as it requires less electricity to manufacture and doesn’t include any harmful chemicals. In recent years, companies like Camira have even started using wool—in conjunction with other natural materials—to produce furniture fabric.

Pros of Sheep’s Wool

• Absorbs sound. Wool is a natural sound absorber and is capable of reducing noise by as much as 50%, allowing for a much quieter and comfortable indoor environment.
• Fire resistant. In the event of a fire, sheep’s wool will not help fuel the blaze—rather, wool only chars when exposed to flames, as there isn’t enough oxygen in the air to support full combustion.
• Humidity resistant. Rather than absorbing ambient moisture caused by humidity, wool actually adsorbs moisture, meaning it traps and stores water molecules inside of its porous fibers before allowing it to evaporate into the air.

Cons of Sheep’s Wool

• Expensive. Regardless of whether it’s used for carpeting or insulation, wool typically costs more than other natural alternatives, thereby increasing the overall construction expenses.
• Susceptible to insect damage. As anyone with an old wool sweater knows, wool is often targeted by moths, silverfish, carpet beetles and other insects, reducing the product’s longevity.
• Chemical treatments. In order for wool to be protected from insects, it must be treated first; unfortunately, most treatments contain unwanted chemicals like borax that have been linked to certain reproductive issues.

10. Precast Concrete Slabs

Traditionally, concrete is mixed and cast on-site, which can make it difficult to maintain a consistent product quality—precast concrete slabs, on the other hand, are prepared, cast, and cured in a highly-controlled setting and then shipped to the project site. This helps minimize waste production, uses less water than pour-in-place concrete, and reduces the amount of soil and water contamination.

Some precast concrete manufacturers, like Fabcon, even use recycled materials in their precast slabs, which helps keep waste out of landfills and reduces carbon emissions.

Today, precast concrete is used to build everything from foundations and walls to bridges and even entire buildings.

Pros of Precast Concrete

• Consistent. Due to the fact that they are produced offsite, precast concrete slabs have a higher degree of quality control and are therefore more uniform in composition.
• Durable. As is the case with poured-in-place concrete, precast concrete slabs are incredibly durable and capable of weathering the elements—and even some natural disasters—with ease; on average, precast concrete is designed to last between 50 and 100 years.
• Low maintenance. Once installed, precast concrete is incredibly easy to keep clean; if left unsealed, precast concrete only needs to be power washed once every 4 – 6 years, and sealed concrete slabs only need to be hosed down every so often.

Cons of Precast Concrete

• Heavy. Precast concrete slabs are, by nature, extremely heavy—this is only a problem due to the fact that they have to be shipped to the project site, and their weight can increase shipping times, which in turn increases transportation-related carbon emissions.
• Difficult to alter. Once cast, concrete is especially difficult to alter; should any last minute changes need to be made to a project’s dimensions, it can necessitate a complete re-cast or redesign of the slabs themselves.
• Can be tricky to install. Due to how heavy they are, precast concrete slabs can be a bit awkward to maneuver and require the use of a crane to lower them into place, which can add to the overall construction expenses.

11. Straw Bales

Straw has long-since been used for construction purposes around the world, and straw bales were used to construct houses in Germany as far back as the early 1600s; in the United States, straw-bale construction has been a staple of Nebraskan-architecture since the late 1800s.

Today, straw bales are used as both a structural component—stacked in rows to form walls, which are then plastered over—or as insulation. When used structurally, straw bales are typically stacked on a foundation and tied together with wire mesh or wood pins before receiving a coat of lime- or clay-based plaster.

Due to the fact that the plants commonly used for straw—rye, oats, wheat, and rice—are easy to grow, are widely available, contain no toxins, and have low embodied energy, straw bale structures are considered to be very sustainable.

Pros of Straw Bales

• Fire resistant. Perhaps unexpectedly, straw bales are actually incredibly resistant to fire damage due to how tightly they are compacted; this makes straw bale construction an ideal choice in areas prone to wildfires.
• Good insulator. The density of straw bales also aids in both acoustic and thermal control, which can help dampen sound and reduce the building’s heating and cooling needs.
• Cheap and easy to produce. Raw straw is an inexpensive material and bales are extremely easy to put together—both of which help cut down on overall construction time and costs.

Cons of Straw Bales

• Can attract pests. Depending on the grain content, moisture, and time before it was baled, straw bales can attract a multitude of pests, including both insects and rodents.
• Susceptible to water damage. Should the exterior shell of the structure crack or start to leak, it can allow water to seep in and dampen straw bales, compromising their integrity and promoting mold growth; high humidity can also negatively affect straw bales.
• Not as structurally sound. If built improperly or if constructed on inadequate soil, straw bale buildings can become structurally unsound due to movement of the bales, which can in turn crack plaster or even allow load-bearing walls to collapse; earthquakes and high winds can also negatively impact the structural integrity of straw bale homes.

12. Recycled Plastic

On average, the United States produces approximately 40 million tons of plastic waste each year—and roughly 85% of that waste ends up in landfills. Due to its abundance and long lifespan, recycled plastic has high potential for use in construction and design: it can be molded into shingles, added to concrete, incorporated into roadways, formed into bricks or tiles, and even used to make recycled-fiber carpets.

As it stands, there is already too much plastic on earth and more is being made each year—recycling existing plastic for mass use in construction projects is one way to help reduce the need for new plastic production.

Pros of Recycled Plastic

• Long-lasting. Plastic is somewhat infamous for its incredibly long lifespan, but this can actually be a plus when recycled plastic is used in construction, as it reduces the need for maintenance and replacement, saving costs in the long run.
• Easily molded. Recycled plastic can very easily be molded into a variety of shapes, a quality that gives it an almost endless array of design possibilities.
• Water- and pest-proof. Recycled plastic is waterproof and does not attract pests like termites or mice.

Cons of Recycled Plastic

• Inevitably produces microplastics. Over time and with use, recycled plastic products shed microscopic plastic particles; these microplastics end up in the soil, air, and water and can leach harmful chemicals into the environment.
• Thermal expansion and contraction. If regularly exposed to fluctuating temperature changes, recycled plastic building materials can expand and contract at a rate that compromises their structural integrity.
• Low load-bearing capacity. While durable, recycled plastic doesn’t have very high compressive strength, making it unsuitable for load-bearing features like columns or beams.

13. Plant-based Polyurethane Rigid Foam

It may be a mouthful, but plant-based polyurethane rigid foam is one of the leading sustainable alternatives to rigid foam insulation. Unlike its predecessor, PPRF does not contain chlorofluorocarbons—a group of compounds that contribute to anthropogenic climate change—making it much better for the environment.

Plant-based polyurethane rigid foam is produced using either a combination of hemp, kelp, and bamboo or vegetable oil and is primarily used as insulation, though it can also be used in furniture.

Pros of PPRF

• High thermal resistance. Plant-based polyurethane rigid foam has high thermal resistance, making it an ideal insulator—it’s so good, in fact, that PPRF actually has a higher R-value than polystyrene and fiberglass insulation.
• Can be composted. Unlike traditional rigid foam, most PPRF products can be composted at the end of their life-cycle; this helps keep construction waste out of landfills.
• Lower carbon emissions. Generally speaking, plant-based polymers are easier to extract than petrochemical-based polymers and subsequently require less energy to manufacture, thereby reducing overall carbon emissions.

Cons of PPRF

• Expensive. Compared to traditional polyurethane foam, PPRF is significantly more expensive; on average, one kilogram of PPRF costs between $18 and $19.15.
• Harder to come by. PPRF is a relatively new material, one that is still being tested and improved upon; as such, it can be difficult to find a local supplier, which can increase a project’s overall construction time and costs.

14. Natural Fiber Insulation

Intended as alternatives to conventional chemical- and mineral-based insulations, natural fiber insulations encompass a range of organic compounds with natural insulative properties, including such materials as hemp, cotton, wood fiber/cellulose, straw, wool, etc.

For the most part, natural fiber insulation is safer to handle and install than traditional fiberglass insulation, as they typically contain fewer irritants and chemicals. Natural fiber insulation also boasts a lower carbon footprint and produces less waste—qualities that many natural fiber insulation companies, such as Greenfiber, pride themselves on.

“Greenfiber uses a low-energy manufacturing process that results in materials with the least-embodied energy of most major insulation products. The production process generates little no waste or byproducts because we leverage recovered material to start with,” Jason Todd, the director of market development and building science at Greenfiber, previously told gb&d.

Pros of Natural Fiber Insulation

• Low- or zero-VOC. Generally speaking, natural fiber insulation contains fewer volatile organic compounds (VOCs) than traditional mineral or chemical insulations, which helps improve indoor air quality and long-term occupant health.
• Fire resistant. Many natural fiber insulations possess natural flame retardant qualities, which helps slow the spread of fire and allows more time for occupants to escape; natural fiber insulations that aren’t intrinsically fire resistant are made so after the fact through the addition of borate.
• Temperature regulation. Predictably, natural fiber insulations are adept at regulating interior temperatures, which helps reduce a built structure’s heating and cooling needs.

Cons of Natural Fiber Insulation

• Can be expensive. Some types of natural fiber insulation, such as sheep’s wool or cotton, are more expensive than their chemical- and mineral-based counterparts.
• May not be as effective. While all natural fiber insulations offer some measure of temperature regulation, most are not as effective as conventional fiberglass insulation—at least, not per inch of insulation material, anyway.
• May require more material. For natural fiber insulation types with lower R-values—that is, insulative capabilities—more insulation material is required to bring it up to par with traditional insulation types; thicker layers of insulation means thicker walls, which can encroach on usable floor space.

15. Mycelium

Mycelium refers to the microscopic network of hyphae strands that make up the vegetative tissue of fungal colonies. When mycelium spores are introduced to organic waste, they quickly grow and send out roots that then consume the waste until all that’s left is a block of mycelium.

This block of mycelium can then be carved or broken into smaller pieces and set in molds to form bricks—some companies, like the New York-based Ecovative Design, even use mycelium to create foam insulation.

Due to its rapid growth rate, consumption of waste material, non-toxicity, and low-emission production, mycelium is an incredibly sustainable material.

Pros of Mycelium

• Highly insulative. Thanks to its molecular composition, mycelium has naturally high insulative properties—it isn’t flammable, effectively regulates temperature, and acts as an acoustic dampener.
• Biodegradable. Mycelium as a building material is 100% biodegradable and can be composted once it outlives its construction purpose, thereby reducing demolition waste.
• Easily produced. One of the hallmarks of mycelium is that it is both quick and easy to produce, without generating waste or harmful emissions in the process.

Cons of Mycelium

• Low compressive strength. Compared to traditional building materials like concrete or stone, mycelium has a very low compressive strength; as such, mycelium bricks cannot be used as load-bearing supports.
• Susceptible to moisture. When regularly exposed to moisture—even just ambient humidity—mycelium becomes less structurally sound and starts to break down.
• Shorter lifespan. As mycelium becomes less resistant to moisture over time, it becomes more vulnerable to damage from humidity and mold—as a result, mycelium has a shorter lifespan than many other building materials.

16. Green Concrete

 

While the term “green concrete” can apply to any concrete that includes added measures to reduce its environmental impact, it typically refers to concrete that contains a high percentage of recycled waste materials such as fly ash, silica dust, slag, and even previously-cast concrete aggregate.

“Rather than dumping asphalt and concrete from construction demolition into landfills, we recycle those materials to be used in future projects,” Nathen Schellenberg, vice president of specialty construction at Geneva Rock Products, previously wrote for gb&d. “On average Geneva Rock recycles 1 million tons of asphalt, concrete, and other aggregate materials every year.”

Green concrete can be used in construction in much the same ways as traditional concrete and has been utilized to construct everything from bridges and buildings to dams and other infrastructural projects.

Pros of Green Concrete

• High thermal resistance. Like traditional concrete, green concrete has a high thermal resistance and is capable of absorbing and storing heat; when incorporated into passive solar design, green concrete can significantly help reduce heating and cooling requirements.
• Utilizes recycled materials. Green concrete makes significant use of recycled materials and helps keep waste out of landfills.
• Low carbon emissions. On average, the mixing of green concrete produces 80% fewer carbon emissions than traditional concrete, as less energy is required to break down the materials.

Cons of Green Concrete

• Higher reinforcement costs. Most green concrete is reinforced with stainless steel, which typically costs more than the carbonized steel rebar used to reinforce conventional concrete.
• Lower compressive strength. In most cases, green concrete has a lower compressive strength than normal concrete, which means it cannot safely support as much weight.

17. Ferrock

Designed as a substitute for conventional cement, ferrock is a concrete-like substance produced by mixing recycled ground-up glass and steel dust with water and ferrous (iron-rich) rock. Once combined, this mixture is then poured and exposed to carbon dioxide, at which point iron carbonate forms, effectively trapping carbon in the ferrock.

After it sets, ferrock becomes extremely strong and can be used for construction in all the same ways that concrete can be used. Due to the fact that ferrock is resistant to both chloride and sulfate damage, it can even be used in construction projects that come into contact with saltwater—a marked improvement over traditional concrete, which erodes in saltwater.

Pros of Ferrock

• Incredibly durable. Thanks to its unique composition, ferrock is resistant to rot, corrosion, chemical exposure, oxidation, rust, and even UV damage; ferrock is also five-times stronger than conventional concrete and has a higher compressive strength.
• Absorbs carbon dioxide. While it’s true that ferrock produces carbon during its production process, it makes up for it by absorbing a higher quantity of carbon as it dries, effectively making ferrock a carbon negative material.
• Utilizes recycled waste. On average, 95% of the materials used in ferrock come from recycled waste products like silica and steel dust.

Cons of Ferrock

• Not suitable for large projects. Ferrock requires a ready supply of silica and steel dust, both of which typically aren’t available in large quantities; as such, ferrock is better suited to small-scale projects.
• Steel dust can become costly. If ferrock becomes more popular, the cost of steel dust is likely to increase, which can make it harder and more restrictive to come by.
• Lack of experience. Due to the fact that ferrock is a pretty modern invention and hasn’t been widely adopted, it can be hard to find construction crews with the necessary experience to create and work with ferrock.

18. Smart Glass Windows

As perhaps the most technologically advanced material on this list, smart glass windows are a truly innovative way for building’s to make the most efficient use of natural light and solar heat.

Also referred to as switchable glass, smart glass windows are constructed using a type of glass that allows for adjustment of the window’s reflective properties. Currently, there are two categories of smart glass windows: electrically switchable and thermochromic.

Electrically switchable smart windows use either micro-blinds, polymer-dispersed liquid-crystal devices, suspended-particle devices, or electrochromic devices to actively adjust the opacity of the glass when an electric charge is applied.

Thermochromic smart glass windows, on the other hand, use what is called a phase-changing polymer to passively adjust the window’s opacity once the glass reaches a certain temperature.

Pros of Smart Glass Windows

• Blocks UV rays. Smart glass windows are capable of blocking 95% of all UV-rays without actually reducing the amount of natural light they let in; this also helps minimize glare.
• Energy efficient. When switched to the opaque setting, smart glass windows reduce the amount of incoming solar heat, which can greatly reduce a building’s need for air conditioning.
• Provides privacy. An added benefit of smart glass windows—especially electrically switchable windows—is that they provide privacy when switched to the opaque setting, making them ideal for use in office buildings.

Cons of Smart Glass Windows

• Expensive. Compared to traditional windows, which typically only cost between $10 and $15 per square foot, smart glass windows are significantly more expensive—on average, expect to pay between $50 and $150 per square foot.
• Requires specialized installation. Due to the fact that smart glass windows are more complex than standard windows, they require experienced professionals to install them; this can raise a project’s overall construction costs.
• Some require electricity. As it currently stands, the most popular types of smart glass windows are those that require an electric charge to switch between transparent and opaque; this can reduce the amount a building actually saves on energy costs by installing smart glass windows.

19. Reclaimed & Recycled Steel

When a building or infrastructural project is demolished, it leaves behind a lot of material, especially when it comes to steel, which is one of the most popular contemporary building materials and often used as the structural framework for large buildings. Fortunately, approximately 90% of the steel used in built structures can be recycled and reused in other projects, either as is (columns, beams, etc.) or, in the case of scrap steel, after being melted down and re-forged.

Ultimately, this helps keep a significant amount of waste out of landfills and reduces the amount of emissions produced by the steel industry.

Pros of Recycled Steel

• Reduces waste. The most obvious benefit of using reclaimed or recycled steel is that it reduces demolition waste and extends the lifespan of existing products—which is almost always more sustainable than manufacturing new ones.
• Saves money. Even though reclaimed steel is practically identical to new steel in terms of quality, it is significantly less expensive, thereby decreasing a project’s overall construction costs.
• Durable. Just like new steel, recycled steel is an incredibly durable material with a very high load-bearing capacity, making it suitable for large construction projects; steel can withstand everything from severe weather to earthquakes and has an average lifespan of 50 to 100 years.

Cons of Recycled Steel

• Difficult to alter. Once steel has been cast and prepped for construction, it is very difficult to make changes after the fact; if recycled steel is available, it may not be the correct size or shape, which can increase overall construction time and costs should alterations become necessary.
• High maintenance. As is the case for any steel product, recycled steel requires frequent maintenance and routine painting to keep it free of rust and corrosion.
• High thermal conductivity. Steel in any form is highly conductive of heat; when it is used as a building’s framework, it can pose both an increased fire hazard and often results in higher cooling loads, thereby increasing energy-related costs.

20. Rammed Earth

As one of the most abundant materials on the planet, it’s only fitting that dirt—or more accurately, rammed earth—is on this list.

Constructed by gradually pouring a damp mixture of selected aggregates (typically dirt, sand, silt, gravel, and clay) in between flat panels or into a flooring mold and then compacting it in successive layers, rammed earth is an age-old building practice that has since undergone a modern revival. Cement or lime is often added as a stabilizer to help improve the load-bearing capacity of rammed earth walls.

As long as adequate subsoil is available, rammed earth structures can be built in just about any biome, even those that receive regular rainfall—provided, of course, that they are properly maintained.

Pros of Rammed Earth

• Readily available. Generally speaking, rammed earth constructs are created using locally-sourced and easily-extracted renewable materials, which significantly reduces a project’s carbon emissions and construction waste.
• Durable. The very nature of rammed earth makes it an extremely durable material, one that can withstand inclement weather, fires, and even seismic activity with ease; if properly constructed, rammed earth structures can last for thousands of years.
• High thermal mass. Similar to concrete, rammed earth has a high thermal mass, which means it is extremely capable of absorbing heat during the day and then releasing it at night; this can help improve energy-efficiency and reduce the heating and cooling loads of a structure.

Cons of Rammed Earth

• Long curing times. Once the form is removed from around a rammed earth wall, it usually takes a full month for the wall to cure and harden completely, which can extend construction time significantly.
• May require additional insulation. Rammed earth’s high thermal mass can help regulate interior temperatures, but it often needs added insulation when built in colder climates.
• Limited uses. Due to the nature of how rammed earth is formed, most structures featuring rammed earth walls are limited to one story (maybe two, if you’re lucky) and are confined to simple floor-plan shapes.

21. Composite Roofing Shingles

Lastly, let’s cover one more example of how the inclusion of recycled waste makes a material sustainable: composite roofing shingles.

Unlike traditional asphalt shingles, composite shingles are produced by combining recycled waste (typically plastic and rubber) with other materials like laminate, wood, and synthetic polymers. Most companies mold their composite shingles off of real slate or cedar shingles, which makes the end result a convincing replica of a much more expensive roofing material.

It should, however, be noted that not all composite shingle manufacturers use recycled materials in their products, so you’ll need to verify beforehand if the sustainable option is what you’re looking for.

Pros of Composite Roofing Shingles

• Durable. Due to their composition, composite shingles are extremely durable and have a very high impact rating, which means you won’t have to worry about severe weather damaging them; on average, you can expect composite shingles to last for fifty years.
• Low maintenance. While this is true of most modern shingles, composite shingles are very easy to take care of—all that’s required is periodic washing with soap and water.
• Versatile design options. As previously mentioned, composite shingles can be made to look like aesthetically-pleasing cedar and slate shingles, but they also come in a variety of colors, making it easier to customize a building’s exterior.

Cons of Composite Roofing Shingles

• Shorter lifespan than true slate. Composite shingles typically last longer than traditional asphalt shingles, but they don’t last as long as the slate shingles they’re designed to emulate, which means they’ll need to be replaced more frequently.
• More expensive than traditional shingles. This is both a pro and a con in the sense that, yes, composite shingles are more expensive than conventional shingles, but they also last longer, which more or less makes up for the added upfront cost.
• Harder to find. Due to the fact that composite shingles are a fairly recent innovation in the roofing industry, it can be difficult to find companies and contractors that actually offer them.

Are Sustainable Materials Nontoxic?

Generally speaking sustainable materials strive to be as nontoxic as possible and many natural building materials have no toxins whatsoever—this does not, however, mean that all sustainable materials are completely free of toxic or caustic compounds.

Many natural fiber insulations, for example, require treatment with borate to protect them from pests—and most sustainable concrete alternatives still contain lime, a caustic compound that can cause chemical burns.

All in all, it’s always a good idea to check which chemicals a building material—sustainable or not—contains before implementing it in a project.

Are There Alternative Sustainable Materials for All Building Materials?

As it stands, there currently isn’t a sustainable alternative for every building material typically used in construction—or rather, it may be more accurate to say that there isn’t a readily available alternative for all types of building materials.

The good news, however, is that sustainable materials are becoming increasingly popular, which means more and more sustainable alternatives are being developed and experimented with every year.

As the number of sustainable building materials increases, the easier it becomes to replace conventional construction products with environmentally friendly alternatives—without compromising the structure’s integrity or its occupants’ health in the process.

Conclusion

Incorporating sustainable building materials into your next project is one of the easiest ways to reduce a built-structure’s long-term environmental impacts, as sustainable materials typically require less energy to produce, minimize or reuse construction waste, and often aid in the sequestering of carbon emissions.

Sustainable building materials also help save money in the long run, even if they sometimes have higher upfront costs, as they are designed with durability in mind and often have very long lifespans compared to their non-sustainable counterparts.

At the end of the day, your project, its occupants, future generations, and the planet all benefit from the use of sustainable building materials.