Green Cities: Hemp 101 for Construction
Like kale and avocado and yoga once upon a time were a niche, going green is on a fast track to its tipping point with the climate clock ticking in the background and advocates screaming for action.
From our clothes, to our products, to the infrastructure of our cities; we're re-envisioning how we function on Earth.
Today’s global market demand for eco-friendly buildings has changed the focus of engineers working in this sector. While creative thinking and sustainable design fuel our pivot to a green economy, hemp is a prime resource at our engineers’ disposal.
The building industry outputs massive amounts of waste, contributing to 39% of global carbon dioxide emissions, and using 36% of global energy use. United Nations Environment Program
A green construction process can help cities become more resilient to environmental disasters, while saving money and contributing to lower emissions.
The success or failure of cities at addressing climate change are pivotal in our efforts to limit global warming.
Green construction focuses on reducing emissions from the lifecycle of constructed assets and from the industry’s value chain at large. IFC
PROBLEM > Deforestation & rapidly rising CO2 emissions
SOLUTION > Green cities & sustainable communities
TOOLS > Hempcrete building materials, hemp insulation, hemp HVAC filters
Hemp in Construction
The woody inner fibers of the hemp plant (hemp Shiv or hurd) are used as a light weight biocomposite building material with a range of performance and environmental benefits.
It's a resilient and breathable, low on toxins, long lasting and recyclable material that combines a variety of properties making it appealing to build with.
It'll keep buildings warm in the winter and cool in the summer due its high thermal mass and low conductivity. Translating to a huge reduction in required energy and a noticeable drop in utility bills. Hemp is a durable, low-carbon, sustainable insulator.
Available in insulation blankets or boards, it can be used for insulating roofing, floors, and even drywall.
Hemp fibers bound with lime create concrete-like shapes that are strong and light. It weighs only one-seventh to one-eighth that of concrete.
Hempcrete hardens from carbonation, and the lime will eventually petrify the hemp and form limestone. It lacks the brittleness of concrete and consequently does not need expansion joints. Hempcrete walls must be used together with a load-bearing frame of another material.
How do we make hempcrete?
Why build with hempcrete?
Flameproof; due to lime and plaster mix.
Mold/Mildew resistant; lime creates an alkaline environment.
Insect/pest resistant; bugs and rodents can’t eat through it.
Vapor permeable; actually breathes.
Can absorb twice its weight in moisture without impacting its performance; ideal for humid conditions.
It’s estimated that 3 acres of hemp could yield enough material to build a 1,500 sq. ft. hempcrete home.
Hemp is a carbon sink. It absorbs carbon (while growing) and even after mixing it with the lime binder it continues to take in CO2 as the mixture hardens, helping to offset carbon emissions created by the production of traditional concrete. Each tonne of lime-based hempcrete is estimated to absorb and sequester 249 kg of CO2 over a 100 year lifecycle
Hemp is a high yielding, fast growing, resource with versatile applications that has a plethora of climate loving benefits.
Uses in construction can help enhance and accelerate the United Nations Sustainable Development Goal 9 - Build Resilient Infrastructure. Since hempcrete eventually turns to petrified rock its buildings can last for hundreds of years, and require little maintenance.
For a deeper dive on how hemp is used and how it can help download our free Hemp 101 for Construction booklet.