Using green construction materials has benefits outside of the obvious environmental benefits. It can be beneficial for health, productivity, and sometimes even the pocketbook. Consider materials based on their source.
Grown and Renewable Material
Building materials that are natural, and can be cultivated are one of the most popular in green buildings, since they can be renewable, and in many cases need little or no processing. These materials can all be recycled after use.
Wood the traditional building material is still popular. It is considered one of the most sustainable. It requires little processing making it low energy-embodied. The Environmental Protection Agency (EPA) recommends using wood certified by recognized accrediting agencies to that the harvest practices and source sites do not damage precious forest ecosystems. These certificates also require that the wood is not treated by "toxic binders, coatings, preservatives, and pesticides."
Worldwide there are 50 certifying agencies and 15,000 companies using certified wood from 700 million acres of forests a scientific article notes. In the USA, the Forest Stewardship Council (FSC), Sustainable Forestry Initiative (SFI), and Green Globes are some of the main certification agencies. The American Wood Council provides detailed information on regulations applicable in different states for wood products. Wood has the widest range of uses.
- Structural and loading bearing components like beams for roofs, wall trusses, panels
- Non-structural elements like window trim, doors, cabinetry, flooring, wall facades, and furniture
Wood is readily available at lumberyards across the country, so call to see what certified varieties your local ones carry.
Bamboo takes five to seven years to mature as opposed to the 50-100 years of other trees like maple and oak used for hardwood flooring. This makes it an environmentally sound. Some bamboo is even harder than red oak. It can withstand some wetting and though is prone to scratches, can be refurnished easily to remove traces of wear and tear and look new again. Homedit recommends checking for Forest Stewardship Council certification to be sure the material is harvested sustainable and treatment will later not produce emissions.
Cork is harvested from the bark of the tree, so the tree itself is not cut down. The bark takes about seven years to regrow, so it's definitely an environmentally friendly choice. Cork is also naturally hypoallergenic and anti-microbial. Its price is also competitive, notes Floor Critics, who consider it being overall an attractive choice. It is widely available on the market.
It can be used for flooring as it has good acoustic and thermal insulation and for shock absorption, points out The University of Michigan (UM, pg. 40).
Palm panels and boards are made from coconut or sugar palm stems after the tree is past its fruit bearing years. Trees as old as 100 years can be used and the raw materials come from Asia. Palm is ideal for paneling, veneer, and flooring according to Home Building. It is available in the U.S. through Durapalm.
Use of this eco-friendly material can be helpful in getting LEED certification, as it is non-toxic, and causes no air pollution. LEED (Leadership in Energy and Environmental Design) certification is for building projects that meet the standards set forth from the U.S. Green Building Council.
Thatch roofs made of hay stacks from water reed, wheat reeds, long straw and ridges are old natural roofing material, with life expectancy of 10-45 years according to Thatch Advice Centre. Though not common, it is still used in UK.
Manufactured Products From Natural Materials
Products can be manufactured using natural raw materials either alone or in combination with others. Their properties, quality, and aesthetical appeal is equal or more than that of conventional chemical or concrete products, so that it is not just the green-conscious users who are opting for them.
Sorghum is a tall millet, whose lower woody stalks are wastes from crops or molasses production that were earlier burnt leading to air pollution. This waste is being used to make boards and panels called Kirei that is polished with natural resins to keep it scratch proof ecologically reports Los Angeles Times. It's used for flooring, paneling, and cabinetry notes TreeHugger.
Being an annual that requires months from germination to harvest, it is one of the fastest renewable building material; and it is non-polluting because it emits no VOCs and has no formaldehyde. It should be possible to grow this material organically to get a completely chemical-free product. Its popularity is growing and is sold through many outlets like Green Building Supply and Kirei.
Cotton insulation is made from recycled cotton materials like scraps of denim leftover during the production of jeans, according to HomeAdvisor. It is usually treated with boric acid to make it fireproof and pest resistant. It is can be used for insulating buildings of various types. In terms of performance, it is as good as conventional fiberglass. In fact, it actually has a couple advantages over fiberglass, as it does not:
- Contain formaldehyde like traditional fiberglass insulation
- Cause skin irritation or respiratory problems.
Since it utilizes recycled material that would have gone into landfill, this material is eligible for LEEDs certification, notes ProReferral. It is available through UltraTouch Cotton Insulation. It is bio-degradable and can the material can be recycled.
Paper is a fragile material but has many applications in building projects. It is made from cellulose pulp, which is waste wood and is recyclable. Some of its uses are:
- Internal and external walls in Japan were made with paper. Since Japan is a region prone to earthquakes, use of this light material caused no or less causalities when disaster struck. There are many types of building elements made. For example, Shoji is made of paper with a wooden frame form a sliding panel. These are still popular as indoor walls in modern Japan, notes Japan Talk.
- Wallpapers are making a come back. Use wallpaper in lieu of paint. It is necessary to buy certified wallpapers that do not emit VOCs, which happen from conventional wallpaper according to Poplar.
An ever-increasing number of fibers are being used to make biocomposites. Many are available as prefabricated particle boards. These are usually made of more than one material to provide complementary properties, and bound by resins according to a Stanford University study. These are renewable, biodegradable, recyclable and more varieties and mixtures are constantly being researched.
Material is sourced from crop residues making use of waste. However given the rise in demand, many high yielding annual and perennial crops are being grown specifically to make bio-composites. The plant material used to make these biocomposites come from:
- Bast fibers derived from flax, hemp, jute, kenaf, miscanthus, cane, crop straw, bamboo, cordgrass, and more according to the Food and Agriculture Organization of the United Nations (FAO)
- Leaf fibers from sisal, banana, and palm
- Seed fibers such as cotton, coir and kapok, according to FAO
Given the different types all ready on the market, the range of uses is wide. Biocomposites are increasingly replacing petroleum and synthetic fiber-based composites. 3-D printing of buildings or elements using bio-composites were tested in the Netherlands in 2016. According to a scientific review (pg. 23, 24, 25, 26), biocomposites are used as:
- Structural elements as beams, panels for load-bearing roof and wall trusses, and paneling
- Non-structural building components like roof tiles or sheets, wall and ceiling insulation, wall and floor coverings, doors, windows, and cabinetry
Natural linoleum is manufactured from natural material that can be grown and are renewable like linseed oil, cork and wood flour mixed with resin binders and pigments. It needs low quantities of energy, and can be disposed safely without any problems, reports UM (pg. 40). It is used for flooring.
Carpets made from natural materials, either from plant sources like cotton or sisal and animal origin like wool, are completely green according to Cadrillo Community College (pg. 12). They have no chemicals and do not emit any harmful toxins. They can be easily recycled as organic material at the end of their life-cycle. It is versatile flooring material that can be changed often and easily.
There are many kinds of natural paints available on the market that do not emit any VOCs and not harmful to health. Many use traditional materials like milk-based casein paints reports UM (pg. 38). Other materials used to make natural paints are plants, minerals, and clay. Mineral and plant based paints have the widest range of colors. Milk based colors need a coat of linseed oil, but are resistant to chipping. Clay based paints are mold resistant and also help in temperature moderation according to Greenopedia.
Natural paints, like those from BioShield, can be more expensive than conventional paints and do not have the wide range of colors that chemical paints do. However they are biodegradable.
Naturally Occurring Materials
Most natural building materials have been in use for a long time since they are easily available, and can be recycled.
Earth and Clay
Earth and clay are the most sustainable building materials, as they require no processing, making its embodied energy practically zero notes Sustainable Materials. Earth can be free if sourced on the site, or entail little transportation cost if removed locally. Clay is a type of soil that is fine textured and has a high content of kaolinite elaborates Countryside Daily. Clay like earth is widely available in the U.S., and with permission can be collected locally or purchased on the market. Earth has been used in many forms in conjunction with specific techniques.
- Rammed earth homes use a formwork made of panels as frame, and a mixture of earth, gravel, sand is rammed in. The whole structure rises layer by layer, explains an Australian Government report. This is a healthy material as it 'breathes' and allows movement of air in and out and helps in temperature and humidity moderation. It is fire and pest resistant, sturdy, and popular in earthquake prone regions. Inhabitat reports that with timber reinforcement and other modern elements, it is still a viable option.
- Adobe bricks are the alternate to burnt bricks. Bricks made of earth and clay need to be fired in a kiln that uses wood and energy, however. Adobe is a process where the mud or clay mixture is compressed in a brick form and left to dry in the sun according to Countryside Daily. Many fibers are also added to increase mechanical stability and increase its insulation capacities, notes a 2016 scientific study that recommends hemp and straw in adobe bricks.
- Wattle and daub also uses a mud and fiber mixture. Instead of making blocks, the paste is directly used as a filling with a framework of timber notes Encyclopedia Britannica.
Stones can be expensive as have to be quarried and their weight adds to transportation costs. Commercial and residential therefore use other materials according to UM (pg.33). However, stones still remain a popular choice if they can be sourced locally. Institutes in particular still use stones for its permanence and low maintenance features.
- It's used to make walls, foundations, in the garden, and as decorative elements in the house like fireplace.
- Marbles of different colors are widely used as counter tops in kitchen and bathrooms, and sometimes as flooring.
Mother Nature News advocates collecting rocks from own properties, or foraging in public areas with permission (of course), and looking for deals at stone dealers. Find the nearest stone supplier using Boral's online resources.
Lime is a mixture of calcium hydroxide and water and has been used for thousands of years. It is mold resistant and improves air quality. It is also nearly carbon neutral notes Curbed, making it a green material that is getting popular again. Green lime stabilized by prickly cactus gel without any chemicals is also available according to Sustainable Build. It is useful as a wall plaster and mortar for building blocks.
Recycled Gypsum Board
Gypsum is natural, but has to be mined. Recycled gypsum, which extends the life cycle of this material, is therefore considered green. Gypsum is calcium sulfate mixed in water to create a white paste. This is usually used to plaster walls directly or used as boards, referred to as plasterboard or wallboard; sometimes dry wall. It is prepared by spreading gypsum on paper and drying it. If gypsum is discarded after a single use, in the anaerobic or oxygen-less conditions in landfills it produced hydrogen sulfite that is noxious and smells of rotten eggs explains Recycle Nation.
Recovered gypsum loses none of its original qualities and can be repeatedly used without any loss of material or function. Recycled gypsum boards are one of those rare materials that are as good as new. Thus recycled gypsum represents closed loop utilization and makes it a green material according to Recycle Product News.
Slate Roof Tiles
Slate is a kind of metamorphic rock that is water-resistant and fire proof. These are natural, with low embodied energy, and can be recycled and reused after they are salvaged. They are used for roofing and cladding walls, according to Green Building Elements.
Salvaged, Reclaimed, and Recycled Materials
Many building materials can be reused if the demolition is done with care so that the different elements can be salvaged. Material for buildings can come other recycled materials too.
Construction and Demolition Materials
Construction and demolition materials usually end up in landfills, However, there are many items that can be salvaged and reused. The EPA recommends considering this use while planning the demolition so that precious material can be saved. It is not just building materials, but various other items that can be salvaged. Find the nearest supplier through Construction and Demolition Recycling Association. Items you may be able to salvage include:
- Dimensional limber, doors, windows, wood flooring, kitchen cabinets
- Stones, marble, bricks
- Bathtubs, sinks, light fixtures
Besides demolition material, wood can be salvaged from shipyards, old wine casks, and old shipping material. Nails are removed, the wood cleaned and milled to reveal the original texture and color, according to Buildopedia. Check with local lumberyards, construction crews, and building contractors to see if they save wood for use in other projects or for sale.
Example Criteria for Certifying Green Building Materials
There are some criteria that building materials have to fulfill to be green according to California Department of Resources Recycling and Recovery (CalRecycle). Criteria considered by various certifying agencies often include:
- Sustainability - Material should be sustainable, renewable, and recyclable; for example, natural and local and grown so the supply is environmentally benign.
- Energy efficiency - Both the production and the resulting energy demand on the building should be energy efficient.
- Quality controlled for air pollution - Green materials selected for construction should not cause indoor air pollution and harm human health.
- Affordability - Materials should be affordable. Even if some costs upfront are high, a reduction in operational costs should help cover the extra initial cost says CalRecycle.
- Waste management considerations - The building materials should not contribute to waste and landfills. The ability to recycle material, or use products made from recycled material that in turn reduces waste, makes products green notes UM.
Lifecycle assessment is used to analyze the effect of a material or whole building in all its phases from production, through transport, use, and operation, on the environment, as well as its "economic and social sustainability" according to Green Building Council and Design Buildings. This assessment is being increasingly used by agencies that certify buildings like LEED and Green Globes.
Many of the green materials go hand-in-hand with special techniques for their use, which in turn requires prior planning. That being said, it is possible to use many green elements while renovating old houses for flooring, wall panels, or insulation, or in interior decoration with just a little forethought.