Transitioning into Natural Materials: Hempcrete

The modern-day construction material choices have made building simple yet very complex. We need to and we should want to transition into building with natural materials.

Once we understand the benefits of natural materials; there is no doubt that we would want to have them integrated into our existing home or build a new one with them.

Natural materials provide benefits that we cannot imagine, its performance is un-real; its actually as real as nature can get. We do not understand nature and natural materials. We need to look at the shelters in villages made out of wood, bamboo, hay houses. This is what a house made with natural material represents houses in BOTH the pictures are completely made with natural materials.

A Natural house in Nepal
A Natural House in USA.

WE NEED TO TRANSITION; but only if we can overcome our fears !.

We have mainstream construction materials that are good (but very bad for the earth and its inhabitants) in giving people the trust that it is strong. What do we need ? A comfortable house. We have been lead in the unsustainable direction making us massively dependent on energy- to cool our houses, to heat our houses, us in the cold.

There have been huge documentation of reports on how bad are the construction materials- cement, paint, plastic products, plumbing adhesives, etc for the inhabitants of the house. We have not been informed. Lead was used in paints before the 1930’s; they got banned stating that children would lick the walls but the real reason was it was helping in absorbing radiation. How much radiation do we have at our homes ? FM, Wifi, mobile, microwave (food), microwave (communications); now all these radiations are not being absorbed anywhere.

Please watch the video below to experience the subconscious fear embedded into all of us of the fear of the wolf blowing our house down.

Now, we know what we are dealing with here, how big the problem looks and how easy the solution is.

Usually a natural home is designed and built in a way to mainly support the roof structure to protect the house from the elements. The walls (light weight) are then added to enclose the house from the side from the elements. We still follow this method in its essence but have replaced the light-weight walls with heavy walls.

Inorder to transistion into building with natural materials or to integrate natural materials into your  existing house, we need to identify the certain components of a house – Structure, Walls, Roof.

Reinforced Cement Concrete (RCC)

We have solutions for structures with Reinforced Cement Concrete (RCC) existing and being used in 99% of  the houses. The half-life-span of RCC maxes out at 50 years. Iron rod reinforcement in itself is very flimsy and cement concrete and very hard and brittle. Both these are combined to make up the structure. Upon any vibrations- earthquakes, they are pushed to the limit till failure in cases where the construction quality becomes very important. The cement concrete will crumble into dust and you are left with the iron rod reinforcement which will also fail upon compression force. Despite these facts, we are massively using this material because we dont see an alternative. But the funny part is, Natural materials are not an alternative how can nature be an ALTERNATIVE. It is mainstream; rest everything; RCC is an alternative construction material. 

This is the most beautiful picture in the world describing a natural material: Lime chemically known as Calcium Carbonate, Calcium oxide, Calcium Hydroxide.

We extract limestone (Calcium Carbonate) from the deposits on the base of mountains: A natural raw material. It is heated at half the temperature of what is required to make cement (using less energy). After heating, we obtain Calcium Oxide: the lime we all know as dangerous one. It will start heating up and boiling when it comes in contact with water.

Once you add enough water, you are hydrating, slaking it, hence called Calcium Hydroxide, Hydrated Lime, Slaked Lime. This is now in ready form for construction. Now something beautiful happens. 

When you have built something with this Hydrated Lime, the carbonation process starts. The water present in the Hydrated Lime will evaporate and the carbon dioxide will start to get absorbed (carbon negative, saving water). You need to apply water to cement to cure it. This will then result into the same Limestone, Calcium Carbonate and the lime cycle can start again if you want to recycle the limestone. This will never expire unlike manufactured cement which cannot be recycled.

The Lime Cycle
Brick Wall

Brick walls are made with bricks (natural material but high carbon emission), cement (high carbon emissions) and sand. Brick walls are then plastered with cement,sand and then painted with 3 coats of plastic paint on both sides. This complete composite wall absorbs heat, cold which radiates indoors, not much insulation from the elements. This is a useful wall for high security and low comfort. These types of walls should be used for safe house, storage etc not to make houses to live in 90% of the time. The problem is not the brick, it is the cement. If cement was manufactured with low carbon emissions, it would be acceptable.

We also need to understand about thermal mass (a property of the mass of a building that enables it to store heat and provide inertia against temperature fluctuations), density and breathability (the ability of a material to allow moisture vapor to be transmitted through the material.) These terms are common natural building terminologies. They already indicate what we are dealing with when we work with natural materials. The parameters drastically changes and the priority changes. We are talking about indoor comfort.


We have transitioned into a different building system; monolithic system. This system allows us to create a sealed concealed indoor environment allowing for maximum temperature, humidity comfort. 

We will compare two types of monolithic building systems to paint a picture of the walls in action, these walls are also alive walls; constantly maintaining the thermal performance.

We will explore the combination of binders clay and slaked lime mixed with filler hemp shivs. Clay is 3 times denser than slaked lime. Clay traps more heat and moisture indoors whereas slaked lime walls is the perfect density to allow for perfect moisture, temperature regulations.

Hemp Shivs

The hemp shivs plays an important role in the wall. It has a very large surface area of capillary tubes which trap moisture vapor into the walls and allow for breathing thus temperature, moisture regulation.

This is a very brief introduction into starting to understand natural materials modern scientific way.


LEVEL 1: If you are building a house and have already built RCC structure, some walls and you still have to build more walls or plaster the brick-cement walls. Transition into a low carbon emissive solution and an improved thermal performance by replacing cement with slaked lime.

SOLUTION: What we are exploring is building a natural wall using fired-clay bricks (natural material with high carbon emissions), slaked lime (natural material with low carbon emissions) and sand. The benefit we get just by replacing cement with slaked lime in plaster and lime-based natural paint will result in low compatibility to heat and cold, hence keeping indoor temperatures comfortable max by 5 deg cooler in summer and warmer in winter.

Brick System
Hempcrete - Monolithic System

LEVEL 2: Replacing brick-cement walls altogether to achieve maximum thermal efficiency and minimum or negative (absorbing carbon from the atmosphere) carbon emissions.

SOLUTION: Using a monolithic building system like rammed earth, hempcrete, clay walls instead of brick systems like fired-clay bricks, AAC, CSEB, Cement Blocks etc.

Brick  system walls have weak points on the joint between bricks that may lead to cracks upon forces acting on the wall and thermal leaks, reducing insulation benefits. 

On the other hand monolithic walls are casted at once with no gaps; the wall can be considered as one brick. These provide maximum thermal performance (we are talking about maintaining 19-25 deg. temperature year-round irregardless of the temperature outside).

Once we understand the basics of natural materials, we also need to implement them into houses. These require knowledge and skills to be able to build with them.

In the modern age, we have traded skilled people for mass-produced industrial products which make work easier. This has 2 effects:
1. People with no skills can now do things. Eg: A layman can now assemble a table with DIY method offered by various furniture manufacturers.
2. Skilled people’s skills don’t get up-scaled, as their skills are replaced with manufactured products. Eg: A skilled person who can apply tile-like finish (tadelakt)  with natural materials; its hard work, lots of polishing to get a smooth surface. Now we have tiles available everywhere; now those skills are lost.

We should recover, learn and pass down as much old hand-skills and knowledge as possible for future sustainability, if we do not want to live dependent on industries and its manufactured products.

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