'Shelter' is a basic human need, and across the world, people are working to create comfortable dwellings every day. Unfortunately, many modern housing construction practices have a significant impact on climate change. This is why concerned industry experts attempt to make building construction eco-friendly, encompassing the ideas and principles around natural buildings.
A natural building is built with renewable resources through eco-friendly technology and is utilized in ways that positively impact the planet.
A natural house was all we could have in the past before the industry invented synthetic construction materials. The purpose of a modern natural building is to reduce the impact a traditional building would have on the environment.
Modern, now traditional, building and construction materials and methods are driving global warming and increasing pollution. The construction industry consumes 3% of non-ferrous metals, 15% of ferrous metals, and 65% of non-metallic minerals3. These resources are not renewable.
Even renewable resources like water and trees are consumed unsustainably, so much so that droughts and deforestation are becoming major concerns.
There are also pollution issues. In 2018, building construction accounted for 36% of global energy use and 39% of energy-related CO2 emissions2. Collecting sand from river beds increases the likelihood of droughts or floods. It also contributes to water pollution.
Air pollution is another issue in the construction industry—building materials like paints, varnishes, and foam release volatile organic compounds (VOCs)1. Fine particle dust from mining limestone and sanding wood is also a problem.
A natural building, common in eco villages, uses many types of natural materials that are easily renewable, recyclable, or both. They are primarily organic and have not gone through manufacturing processes that pollute the environment.
Non-organic organic materials like plastic and steel find their way into a natural house in the form of pipes, fasteners, and so on. When using plastics, opt for their recycled form.
Let's take a look at some building materials used for natural buildings.
Since we are talking about natural buildings, it shouldn't surprise you that the number one material is the soil itself. Mud, clay, soil, earth, whichever name you prefer, is usually mixed with other materials such as straw, cement, wood, and sand. Sometimes, it is used alone without any additives.
The most popular type of earth or soil-based building is the cob structure. It is a monolithic building system that was widespread and still exists today.
Cob is a mixture of mud, water, sand, and straw. Natural builds use the mud mixture to create walls or use it as mortar. Another way of using soil for a building is by filling burlap bags with earth, which natural builders call earthbags. People stack the synthetic or natural fiber earthbags to form walls, foundations, and footings.
Earth buildings have thermal mass, regardless of the methods used. We also have light and rammed earth walls methods. Both methods use the rammed earth technique, but while a light earth wall contains straw, a rammed earth wall does not.
These are clay bricks made with a mixture of clay, straw, and water. They use molds to form the bricks and leave them out to dry. Adobe bricks do not go through kiln drying at all, just sun drying. When the blocks are ready, they begin building with them, keeping them together with clay mortar. We've used adobe from ancient times through to today.
Adobe is fireproof, non-toxic, strong, and biodegradable. They also have high thermal mass, providing excellent insulation and ventilation. Because each block contracts as it dries, there's little chance of adobe walls forming cracks. Adobe bricks have considerable water resistance and allow much flexibility in designing and constructing earth buildings.
Wood has a smaller carbon footprint compared to concrete or steel. Despite concerns about deforestation, wood seems to be unavoidable in construction. That's why natural building advocates push for eco-friendly timber consumption.
To do this, they use sustainably harvested wood or salvaged wood that has been used before.
Timber from sustainable forests has a certification to that effect. Shipping crates and pallets, solid waste streams, a building site, or a remodeling site are some of the best locations to salvage. There are also timbercrete panels made from a mixture of sawdust and cement.
The concern around fire hazards is why a lot of people avoid timber and go for concrete instead. In natural buildings, timber can be used in cordwood walls, timber frames, walls, floors, windows, and stairs. However, cross-laminated timber (CLT) is a type of prefabricated timber panel treated with fire resistance.
Truly eco-friendly natural buildings avoid unsustainably harvested wood and toxic preservatives.
Bamboo is widely used across many industries. The plant has a significant advantage of rapid growth. Bamboo cultivation doesn't require pesticides, insecticides, or herbicides. Farmers harvest it sustainably and do not need to replant it after every harvest. Bamboo will grow right back from the rhizome root system.
As a building material, bamboo has excellent tensile strength; it's often compared to steel and is incredibly durable. However, without treatment, bamboo is susceptible to rot and mold. There are a variety of ways to treat bamboo using synthetic or natural ingredients. We recommend natural methods like heat or saltwater to avoid exposure to toxins. They drill small air holes into bamboo slats to prevent cracks or coat the ends with beeswax.
This material is called different names, including canosmose, hempcrete, canobiote, isochanvre, or hemp-lime. It is a composite slab for creating non-load bearing walls, wall insulation, ceilings, roof insulation, and floor slabs.
Hempcrete is an agricultural by-product made from the shive or hurds (the chopped-up wooden stem) that result from processing hemp. The shiv is mixed with a lime-based binding element, making it possible to press the shives into molds.
A hempcrete block weighs much less than a concrete slab of the same size. It has a high thermal mass and can handle more moisture than other plant-based Insulation solutions. Hempcrete won't get moldy, cracked, or infested by termites. It won't shrink and may even gain strength over time.
The hemp plant sequesters carbon and so using hempcrete as insulation also helps fight climate change. Also, hemp cultivation consumes very little agrochemicals and water.
Straw is one of the best natural materials available. The material is a by-product of agriculture, and as such, we upcycle it by building with it. When stacked in compressed bales, straws pack a lot of strength and provide great insulation. Advancements in agriculture mean that you can get straw bales in a standard size, just like a stack of bricks.
There are two major approaches to constructing a straw bale building. The first is to use the bales as a structural load-bearing component to support the roof, doors, and windows. The other way is to create the building frame with timber and fill in the wall cavity with bales of straw. That way, the bales only serve as insulation and plaster base.
The second approach is deemed safer and sees more approval from local building councils than the first. It is important to keep the straw bales away from water while building, especially if you are using a straw bale stacking method.
Urbanite refers to chunks of salvaged concrete from demolished sidewalks, houses, and other projects. When you use urbanite, you are recycling concrete. The material is surprisingly easy to get; you can even get it for free at a demolition site or urbanite dumps. People use urbanite for walkways, retaining walls, flooring, patios, and much more.
Stone is a natural building material home construction has used for ages. It is no longer as popular because of the intensive labor and costs. Also, it is not very sustainable to quarry stones since humans cannot renew rock formations. However, stones are highly durable, so that you can build with stones from other torn-down stone buildings or discards from other uses.
Cork, a strong building material, is harvested from the bark of an oak tree without the need to cut them down or damage them. It is resistant to fire, doesn't absorb water easily, and is resistant to abrasion.
They make some floor tiles and insulation sheets with cork. It is used for countertops, exterior finish, floor underlayment, acoustic wall coverings, and countertops.
Some construction materials are made with plastic polymers. Although plastic is not an organic material, we can recycle it. Some types of concrete slabs are made with a recycled plastic mix, PVC windows, carpets, pipes, and cables too.
So, as great as it would be to have an all-natural house with zero plastic, electric cables and water pipes are essential. Recycled plastic helps to reduce the greenhouse gases associated with extracting new resources. One great advantage of recycled plastic is that it allows us to conserve resources and reduce pollution.
Apart from materials, another aspect of natural buildings is their methods. The construction process must pass the sustainability test as well. The factors that help to decide the best approach to constructing a natural building include the building site, local materials, and climate conditions.
To erect walls of a natural building, a common choice is straw bale walls. They are used as load-bearing walls or as in-fills. Load-bearing straw bale walls are easy to set up but filling in wall frames with straw requires more time.
One of the most popular natural building methods is rammed earth walls because of their high thermal mass. Natural builders pound the earth mixture into movable frames (formwork) to form the walls. Natural buildings with rammed earth walls require solid foundations and thick walls because a rammed earth wall must load-bear.
To manage space, you can use light earth walls for non-load bearing internal walls. They make light earth walls by coating loose straw with mud and pressing the mixture into a formwork.
Cob walls are a very ancient natural building technique. It involves mixing mud, sand, loose straw, and water in a container and using the mixture to create walls. The process is a hands-on experience as it is done by hand, like building a giant sandcastle.
Sometimes, builders mix cob and debarked wood to create a wall with good thermal mass. Cordwood walls make stylish exterior walls. They layer the timber chunks crosswise using the cobb mixture as mortar. Sometimes, the mortar they use is cement. Cordwood walls make
Using wood planks as a roofing material has been practiced for centuries. It is a durable and eco-friendly solution but comes with regular challenges; fire, rot, and pest attacks. Natural builders can solve those problems by using CLT timber shingles and periodic treatment with non-toxic wood preservatives.
They make thatched roofs with materials like straw, water reed, rushes, sedge, palm leaves, seaweed, heather, and so on. This eco-friendly roofing system offers excellent insulation even without an added layer of insulation material. With regular maintenance, it can last for decades.
Bamboo has more resistance to rot and pests due to its high silica content. But it still needs preservative treatment, for which there are all-natural options.
A living roof, also called a green roof, is a roof that doubles as a garden. They help capture CO2, keeping the building insulated and reducing rainwater runoff. However, they cost a lot of money due to their structural requirements. Also, plastic waterproofing features in modern green roofs, and ideally, it should ideally be sourced from recycled materials.
Earthen or poured adobe floors are not new and are traditionally just clay that's tamped down. Now clay is mixed with straw and sand, then polished with natural oil or wax. The finish keeps it shiny and water-resistant. You can lay earthen floors directly on the ground, compacted gravel, concrete, or a wooden subfloor.
Since cork is water-resistant, it is suitable for any space, including bathrooms and basement floors. The cork boards can be glued down or prefabricated to click together. The major problem with cork flooring is that sharp objects can scratch and damage it easily.
Timber may be unsuitable for rooms that may be exposed to moisture often, like the bathroom. Even in other rooms, wood flooring would need water-resistant treatment. Timber floors are very attractive, but they can be scratched easily. But using maintenance products like wax, oil, or lacquer, you can hide scratches.
Stone tile flooring or regular stone floors are pretty expensive in terms of labor. And if the material is not locally available, the cost increases. However, stone flooring is highly durable and completely eco-friendly.
Ceramic tiles are made with an abundant material; clay. Extracting the raw material is not harmful to the planet. Kilns release CO2, but ceramic tiles can last for decades, offsetting the carbon costs. Although ceramic tile floors require expert installation, they are not fragile once laid. They are resistant to dents and scratches and are also suited to wet environments.
A house can be designed to ensure it consumes less energy and is easy on the environment during use. Modern natural building techniques take issues like space, natural ventilation, and water recovery into account.
Builders use natural or passive ventilation that reduces the energy consumed by air conditioners or other mechanical cooling systems. They also integrate water conservation systems like rainwater collectors and grey water recycling. For lighting and energy, they use skylights, solar panels, and other sources of green energy.
A natural building is environmentally friendly without taking away the comfort and safety that a human needs. The best way to construct a natural house is to use locally available resources as much as possible. Importing a lot of foreign materials will increase your carbon footprint print. Also, local materials are usually less expensive overall.
United States Environmental Protection Agency, EPA (2021) Volatile Organic Compounds’ Impact on Indoor Air Quality EPA.gov.
Global Alliance for Buildings and Construction. 2019. 2019 Global Status Report for Buildings and Construction
Key International Resource Panel. 2021. Analysis of the Construction Value Chain
Jen’s a passionate environmentalist and sustainability expert. With a science degree from Babcock University Jen loves applying her research skills to craft editorial that connects with our global changemaker and readership audiences centered around topics including zero waste, sustainability, climate change, and biodiversity.
Elsewhere Jen’s interests include the role that future technology and data have in helping us solve some of the planet’s biggest challenges.