Potential of Hemp-Lime Materials in Constructing Carbon-Negative Houses

Building materials are one of the components that should be considered while constructing an environmentally friendly structure. Because of this, cement substitutes, such as materials made from Hemp and lime, are gaining popularity. On the other hand, it is said to be capable of producing nearly no carbon emissions when a house is being constructed.

(Photo : Dezeen/Kaja Kühl )

Sustainability of Using Hemp-Lime Materials

Alongside issues caused by unyielding surfaces and low insulation, or R-value, properties, the cement industry contributes to approximately 8% of carbon dioxide emissions that contribute to global warming. As mentioned, Hemp-lime-based construction materials that are low in carbon emissions and favorable to the environment are an example of an intriguing near-scale alternative, while the search for large-scale alternatives has thus far produced few fruitful outcomes.

Architect Kaja Kühl, part of a Columbia University program to help implement environmental measures in the Hudson Valley, finished the construction of two cottages on a farm in upstate New York using hemp-lime, known commercially as hempcrete. Due to the blocks' lack of load-bearing capacity, the material is primarily utilized for heating and cooling insulation and internal wall construction.

On the experimental agricultural incubator of Wally Farms, two rental cottages designed for upstate farmland utilize lumber and prefabricated hempcrete bricks to reduce their carbon footprint. In his article, Kühl highlights a developing network of advocates, designers, and manufacturers who find bio-based construction supplies to significantly lower the embedded or upfront carbon footprint of products that, in some cases, account for 80% of the carbon life cycle of the material.

However, attention has recently been drawn to its capacity to sequester carbon at a rate twice as fast as conventional forestry or more than twice its weight. It has been estimated that Hemp has the potential to absorb up to 15 tons of carbon dioxide per hectare through the process of photosynthesis. Accordingly, a gap of 23 gigatons of CO2 per year in the United Nations' emissions would be closed if hemp farming were to take up merely 25 % of the world's agricultural land used for dairy and livestock production. Thus, Hemp, according to proponents, provides numerous environmental advantages that policymakers and architects consider when developing a carbon-neutral, weather-resistant, and fire-resistant product.

Also Read: Discover 5 of the World's Smartest Buildings: Blending Design With Technology

Drawbacks of Using Hempcrete Material

As more environmentally conscious building solutions become available, there is a growing interest in Hemp as a potential replacement for traditional building materials. Numerous businesses, such as rope, textiles, and biofuel, currently use Hemp as a raw material. However, building hemp systems is hindered by high prices and a supply network that still needs to be fully constituted. As a result, advocates need to overcome opposition to a product that is frequently and incorrectly associated with the use of drugs for recreational purposes.

Moreover, no information is currently available about the endurance of Hemp concretes, and it is impossible to guarantee that a minimum level of thermal, hygrothermal, and acoustic performance will be maintained for a specified amount of time. Considering this, there are still some limitations that limit the utilization of these biobased materials used for insulation.

It is reportedly dependent on the conditions of their use and the environment to which they are subjected that the qualities of hemp concrete will change over time. These changes in chemical and microstructural qualities are brought about by factors such as temperature, relative humidity, liquid water, and ultraviolet radiation; the functional properties are altered. Investigations conducted in the past have demonstrated that water has various effects on the characteristics of hemp concrete. The hydrophilic nature of hemp shiv causes aggregate swelling, which increases stress at the vegetal particle-binder interface and reduces the mechanical attributes of hemp concrete.

Related Article: Exploring the Eco-Friendly Advantages of Soil-Cement Bricks in Construction