Building with rammed earth is simple, pocket friendly, and sustainable. Contrary to popular belief, rammed earth construction is feasible in a wide range of climatic zones, including areas with a significant monsoon. A built rammed earth structure is a sight for sore eyes, it is a dense but breathable material which makes it great for thermal insulation. With the right processes and tools, a rammed earth structure can easily be implemented by anyone. Here are some basics about the natural material to help you get started.

Knowledge Partners: Gia Mantra Global Village

For a detailed analysis of Rammed Earth as a building material, watch my conversation with natural building expert Donald Sequeira here.

We also answered the FAQs on Rammed Earth recently. Find the Q&A session here.

In part two of 'Building with Rammed Earth', I speak to Donald Sequeira. Donald is an architect, natural builder, and the Director of Gia Mantra Global Village in Tiruvannamalai, Tamil Nadu, India. In this conversation, we take a deep dive into questions from students, practitioners and sustainability enthusiasts to clarify concerns regarding rammed earth as a building material. Through this Q&A session we touch upon various aspects including:

• The Building Process

• Strength of Material

• Potential of Construction

• Climate Feasibility, and

• Maintenance

Here are some interesting questions that we received over the course of the IG Live session:

1. Can a rammed earth structure be built in areas with heavy rain?

   A rammed earth structure can be built in any climatic zone including areas with heavy rainfall. The precaution to be taken is to ensure large overhangs are given to protect the wall from the rain. Additional surface treatments like waxing or plastering protect exterior walls for a longer period.

2. What is the ideal soil type for rammed earth?

   Yes. Rammed earth walls can be built out of most local soils but the clay content should not exceed 30%. If the clay content is higher, the soil can be mixed with other soil types or washed with water to dilute the clay concentration.

3. How are building services addressed?

   The electrical conduits and plumbing must be inserted while ramming. Prior planning is required. Otherwise, services can be added later but those surfaces may require plaster.

4. Are any surface treatments possible?

   Yes, rammed earth walls can be plastered, painted, and tiled over like any other wall. Clear treatments such as wall waxing are also possible.

5. Can river sand be added to the soil mix to reduce the clay content?

   Yes. However, river sand is not ideal because it is not a sustainable source. M-Sand is a good alternative to river sand and can be used as one of the mixture components.

6. Can a 4" rammed earth wall partition wall be created inside a RCC framed structure?

   A 4" rammed earth wall may not be possible since very little space is available for ramming. Furthermore, if the wall is planned beneath a pre-existing beam or a slab, it becomes harder to ram the top portions and close the gap. CSEB is a good alternative for built framed structures.

In this IG Live, I speak to Donald Sequeira. Donald is an architect, natural builder, and the Director of Gia Mantra Global Village in Tiruvannamalai, Tamil Nadu, India. In this first part of our conversation on 'Building with Rammed Earth', we understand the fundamentals. We understand the potential and constraints of rammed earth as a material and learn about preparing the material for construction. We speak about the material's strength and stability and understand construction concerns such as building height and services. We also discuss the durability and maintenance of rammed earth over its lifetime.

Here are some common myths about rammed earth debunked:

• A rammed earth structure can be built in all climatic regions.

  Rammed earth can be used for construction anywhere. It is a breathable but dense material that offers great heat exchange in tropical areas and thermal insulation in extremely hot or cold regions.

• A rammed earth building is durable and has a lifespan greater than concrete.

  Rammed earth structures also possess strength that is at least equal to the strength of concrete. They are extremely sustainable in the long run and require minimum maintenance.

• Rammed earth walls do not have to be very thick and there is no limit to room sizes.

  For a ground floor structure, only a 9" rammed earth wall is required which is equal to the thickness of a brick wall. As long as this criteria is met, it is possible to create spacious rooms of various sizes with rammed earth.

• There is no threat of insects or pests entering the house through the rammed earth walls.

  Once compressed, the rammed earth wall becomes extremely hard and dense. While the material is breathable, it is not not porous. The density does not allow for passages to be made by pests.

The feeling of being inside a rammed earth structure is indescribable. The structure changes with the weather to protect you. It has a quiet, special, womb-like quality - one instantly feels cocooned.

In this IG Live, we speak to Dr. Ajit Gokhale, the founder of Natural Solutions, India to discuss ‘Building Reed-bed system for Wastewater Management’.
Over our conversation, we get into details about the components of a Reed bed system, how the water purification is carried out, and the right methods of implementation. We also debunk common misconceptions about reed beds such as odor and maintenance requirements. Finally, we speak about the different types of flowering and fruiting plants that can be used for reed bed systems in Goa and along the Western Ghats.

Natural Solutions aims to spread environmental literacy and offers sustainable solutions for Urban as well as Rural Problems of water scarcity, Solid Waste Management, and wastewater treatment. Here are some key takeaways from our conversation.

Debunked myths about reed-bed systems

• A reed bed system does not smell if designed correctly. The simple precaution of introducing the inlet pipe at the bottom of the reed bed and not the top of the ensures that no foul smell is emanated.

• A reed bed does not have to be designed in a segregated area. It can very much designed as part of the landscape to be a walkable, usable space that can be accessed regularly.

• A reed bed can be used to effectively purify not just greywater but also black water and industrial wastewater when implemented correctly. It does not require significant additional maintenance.

Maintaining a reed-bed system

• A reed bed system typically consists of two parts - a sedimentation system (a septic tank/ an anaerobic digester/ Jalrakshak) and a filtration system (the reed bed itself). The entire system requires very little external care or maintenance.

• As with any common drainage or waste treatment system, the septic tank/ anaerobic digester/ Jalrakshak has to be cleaned occasionally.

• The reed bed itself does not require any maintenance. The plants can be trimmed for aesthetic value but it is not necessary. Trimming does not hamper the reed bed system as long as it is done as per a pruning schedule. Care has to be taken that the base of the plants are intact.

Benefits of a reed-bed system

• A reed bed system is a one-time investment with lifelong benefits. It is extremely low maintenance in the long run.

• Depending on the microclimate, the reed bed can purify every 1L of impure water to create 0.7 to 0.9L of filtered water that can be reused.

• The filtered water can be reused for irrigation & gardening, washing cars, and for flushing.

• The reed bed can be integrated as an accessible part of the landscape of the house with flowering and fruiting plants and trees that become home to local biodiversity.

Reed beds are sustainable, scalable, cost-effective ecologically engineered systems that can effectively purify wastewater. They are easy to maintain and can be designed into the landscape irrespective of the project size or typology.

Sustainable building is not as complicated as it sounds. Here are 5 simple practices to adopt while building which offer lifelong benefits and returns:

01. Harvest rainwater for reuse or to restore groundwater. Even a system as simple as a collecting tank makes a difference.

We have a conversation covering the basics of rainwater harvesting. Watch it here.

02 Source and use materials and natural stones that are local to the place.

Read about optimal use of local materials in this article.

03 Preserve existing trees and use native species. Use flowering & fruiting trees & plants to retain the habitat and welcome biodiversity.

Find out more about natural landscaping here.

04 Maximise daylight and cross ventilation by creating openings on at least two sides of a space.

Find out how to connect to the outdoors in this blogpost.

05 Create pathways and hardscape with permeable paving to allow rainwater to reach the ground and replenish the water table.

Learn more about designing outdoor paving here.

Photograph of Nivim, by Bharath Ramamrutham

The opportunity to build on a contoured site can be both a challenge and a blessing. Even as it requires unique structural solutions, a contoured plot of land offers great design advantages. The sloping site automatically facilitates unobstructed views. It allows the building envelope to feel like a private sanctuary because there is no close visual connection with other neighbouring buildings beneath or above. The rolling site terrain also allows the architecture to cascade, creating multiple distinct ways of experiencing the space and its surroundings. For our houses in Goa, we use the following principles to build on terraced sites sensitively and sustainably.

• When we build on a contoured site, we refrain from cutting or filling excessively. As a principle, the land topography is retained as much as possible.

• Every contoured site speaks a unique story. The soil, water and vegetation indicate how the site fits into the regional topography. The natural paths created indicate how water flows through the site from higher to lower contours. While designing, we like to take a site positive approach and make minimum alterations to these existing natural systems. This ensures that we are not tampering with the natural water flows within the site, hence avoiding any unexpected flooding during the abundant monsoon in Goa.⠀

• We also like to keep the site land around these water channels permeable without any cement cover. The natural paving ensures that there is a simple but high functioning rain water harvesting system where water is allowed to percolate into the ground and does not flow down and away from the site, preventing any water deficits in the future.

• One of our first steps on any site is to understand everything there is to know about the greenery. The kind of vegetation usually indicates where the water collects on site and shows the different kinds of life forms within the site. It helps in developing a cohesive ecological response strategy while designing.

• Understanding the vegetation also helps us design and build with nature. Unlike flat sites, where one would typically only see the base or trunk of a tree from ground level, a contoured site allows one to interact with the dense foliage of a tree on a higher level and the woody bark of another tree on a lower level simultaneously. We try to find these vistas to celebrate and curate through architecture.

• We look for terrain and topo sheets to place the site inside its regional context. Most of these sheets are easy to access, available online, and are often on university websites. Once we have an initial understanding of the levels, we model the site in 3D using software such as Google Earth, SketchUp, and Rhino. Most of these software also allow us to geo-locate our contoured plot to check for accuracy.

• While proposing a design, we usually look at a maximum of a 1m level difference from one space to another. This is done to avoid cutting and filling as much as possible and to move with the land terrain.⠀

• We love to use a material palette that is either sourced locally or naturally and build using local construction techniques. We take cues from the surrounding sites and buildings around us to identify the most effective and least intrusive construction methods for every piece of land we build on.

Practicing these simple steps helps us to build sustainably and design houses that are gentle on the land they stand on. To know more about the methods, tips, tricks and processes we follow while designing, visit our blog series, Designing A House In Goa.

To the jaded, the mention of green buildings implies a marketing gimmick, and to an idealist, it conjures images of buildings built with mud and bamboo with compostable toilets. Invoking a strong response either ways, we recently concluded a Q&A session on Green Buildings on Instagram. The session had over 300-people join over the course of a 30-minute session. 

The first question that we tackled was, ‘What is a Green Building’? My answer, ‘A green building is one where you’re trying to reduce the impact of the building on the environment.’ It is about making the right choices at every stage of the project, with the ultimate goal to minimise one’s footprint on the environment. To make a building green, the architect must treat the environment as a key design criteria from the first step of the design process right until the occupancy stage. 

It is our commitment to build sustainably and we green certify all our houses in Goa. Our first home, Nivim was the first green certified residence in Goa. It received a gold-level certification and our project Navovado has recently been awarded the platinum-level certification by the Indian Green Building Council. Platinum being the highest level available in the ranking system.

While a building can absolutely be green without a certificate, a green certification is a great way to stay accountable to oneself throughout the design and construction process. It provides the involved professionals with a detailed list of checks and balances with specifications and design criteria that need to be considered and incorporated at every stage of the design and construction process.

In India, TERI (home-grown) and IGBC (offshoot of USGBC) are the primary agencies that issue green certifications. Both these organisations use a credit based system for the evaluation of green building design and performance. The credits fall under the following categories: Site Planning, Water Efficiency, Energy Efficiency, Indoor Air Quality, and Materials among others. Throughout the process, extensive documentation with detailed calculations are required which is then reviewed and tested by the certification body on site. While the system is elaborate, it proves effective as a way to stay true to one’s goals of sustainability. However, it is important for architects to avoid incorporating design elements or features, just for the sake of securing points and focus instead on strategies that are feasible for that specific project life cycle and use.

Demystifying Green Building

I would like to cut through the clutter on this topic. Specially as I would like to demystify the concept and express that green building design is not necessarily a specialized science, nor is it forbiddingly technical where only certain qualified professionals can build green buildings. On the contrary, it is my strong belief that a building built with the basic principles of good architecture would do very well on the green scorecard. The process of green building design starts with a deep understanding of the site, local climate, wind patterns, local materials and resources. Once a building is sited to take advantage of the sun and wind to maximize daylight and cross ventilation, is designed to be responsive to the weather patterns and is built using local materials, then that in itself is a great start towards making the building green.

In the predominantly hot and humid climate in India, one can further think of reducing the heat gain through an informed design of the building envelope. This will have a tremendous impact on the thermal comfort within a building and hence reduce the energy use in the building. Water is another key natural resource that is dwindling with increased human activity on our planet. Rainwater harvesting provides a simple (sometimes ‘no-brainer’) solution to this problem. The idea is simple, instead of allowing rainwater to drain away from your site, one can design systems to either collect it and reuse on the site itself, or feed it back to the earth to recharge the underground aquifers. In addition, a simple introduction of dual flushes can reduce water use by 50-60% and aerators to taps, which can reduce the water use by upto 70% percent. Aerators mix the water from the taps with air, and as a result the water pressure feels the same even when the amount of water flowing through the taps are reduced.

When it comes to building materials, it is wise to use local materials. In most cases, the vernacular building techniques and the local labor would be well versed with the local material. The green quotient of buildings can be further increased by choosing materials with a higher recycled content, higher recyclability, reusing salvaged materials and materials that are rapidly renewable such as bamboo.

The choices to go green are not always straightforward. Cement for example presents a big conundrum in the building industry. The production of cement produces large quantities of CO2, a greenhouse gas with a lasting impact on global warming and climate change. In fact, the production of every kilogram of Portland cement produces an equal amount (one kilogram) of CO2. This presents a huge challenge for our industry where the widely accepted structural material is cement. Wood is another material that presents a difficult choice with sustainability. On one hand, it is a naturally renewable resource and is biodegradable, and wood can be used and reused multiple times. But at the same time, we are cutting irreplaceable virgin rainforests at an alarming pace with long lasting disastrous impact.

Finally, a green building doesn’t have to cost a lot more. Majority of green building strategies are common sense and based on sound architectural principles, which do not come with an additional cost. In addition, there are simple systems that are available at extremely reasonable prices. The aerators mentioned earlier are a free addition offered by most companies that sell sanitary fittings. The difference is for the architect, client and the vendor to be aware of these systems and integrate them into the building design in a timely manner. 

We must as a community of architects pledge to make green building design as important as aesthetics in our projects. A simple change in the thought process can have a long lasting impact on the quality of life for our future generations, which is a cause worth fighting for.

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How does one build in a rural location with the objective to have minimal or zero-impact on the environment?

This question is the primary driver behind the site planning strategy for The House with Three Pavilions located in Goa, India.

The project site is located on the edge of rice paddy fields with a dense cluster of local forest trees on one side and a coconut grove in the middle. The following diagram illustrates some of the critical measures taken as part of the site planning strategy.

WHY IS AN ECOLOGICAL RESPONSE ADOPTED?

• As Goa gentrifies, rampant new construction threatens to rock the delicate balance between nature and man. This project is our attempt to showcase that the built form can tread lightly on the land with conscious design and measured planning. 

• The design focus is to leave a minimal or zero-impact on the functioning natural ecological cycles at the site that pre-date the new construction. 

• The site is geographically located along the path of the watershed from surrounding higher elevations that finally drains into the Arabian Sea. The design planning is oriented to support and improve the water movement through a comprehensive water management plan.

• The water management plan is implemented to address three primary concerns around the site - to recharge the depleted underground water table, to increase water availability for the paddy fields bordering the site, and to reduce the water load on the Municipal Draining system.

WHAT HAS BEEN DONE?

• During the survey, a natural depression was found at the center of the site with a perennial wetland hosting diverse flora and fauna. This existing depression was dug out (until the underground water level in the driest month) and integrated with the existing well on the site. Today, this natural wetland feature is preserved and developed into a seasonal waterbody which also forms the focal point for the landscape created using a native planting strategy.

• All the roof rain water runoff is captured and along with the site surface runoff, it is directed into the central seasonal pond for rain water harvesting. The edges of the pond were formalized with mortar-less retaining walls built in local laterite rubble. This was done to reduce the erosion of the pond edges and to retain the water as a permanent feature in the landscape

• The pond was further connected to a newly planned system of bioswales that spread the collected runoff water over a larger site surface area increasing the rate and extent of percolation on the site. This keeps the level of our underground water table high throughout the year and the soil moist, reducing the garden irrigation requirement in the dry season.

• The bioswales use no cement in their construction and can absorb water through the walls and the base. The construction of the bioswales and the pond without cement, also allows for the water to remain clean without any toxicity of the cement leaching into the landscape.

HOW DOES THIS CREATE A POSITIVE IMPACT?

• The water management was a critical part of this project and offsets the load on the rudimentary public storm water systems found in the Goan villages especially during the heavy monsoons.

• As a result of our efforts, the underground water levels have been improved hence negating the impact of the house construction on the environment. We have been able to prevent any additional flooding at the neighboring fields or any other low-lying area in the village. 

• The project also prioritises the enhancement of the site’s resources and biodiversity. In doing so, it also creates a positive impact on its surroundings by protecting the agrarian viability which is constantly threatened by new construction and increased human activity. Our success can be measured by the number of birds, reptiles, butterflies and insects that can be found on the site today. We have uncovered peacock eggs, cuckoo eggs and baby parrots on our site. It is a win to see that the animals continue to find the site a safe space even as they come in close contact with the human life around, making this truly a space for all seasons and species.

(Water Management Plan in consultation with Pallavi Latkar and team at Grassroots Research Mumbai.)

Our project Navovado has recently been awarded the Platinum-Level Certification by the Indian Green Building Council. Presently, the Platinum Rating is the highest level available in the ranking system awarded by IGBC, the Indian Green Building Council.

With a total of 60 points out of 75, Navovado won the platinum rating from the Indian Green Buildings Council. The credits were awarded for the various green features of building under the following categories:⠀

• Site Selection and Planning.

• Water Conservation.

• Energy Conservation.

• Materials Conservation.

• Indoor Environmental Quality and Occupational Health.

• Innovation & Design Process.

Site Planning, Green Cover and Landscape:

The Navovado site came with 6+ trees on site with some beautiful mango trees and shrubs of different kinds. All of these trees are left untouched on site with the building footprint set at the center, at a safe distance to leave the roots undisturbed.

The landscape plan at Navovado looks at cover from earth to sky, from creepers and grass to tall trees with canopies. At the beginning of construction, our priority was to ensure that we did not lose the top soil. Hence along with the building footprint, planters were incorporated as a first stage detail to conserve site soil on site itself.

Native plant species were selected for plantation based on visual diversity, water consumption, what kinds of animals it would attract and how seasonal the species is.

Water Conservation and Rain Water Harvesting:

Water conservation was a priority throughout the process. Rainwater Harvesting in Navovado has been done from all roof and landscape areas to enhance the ground water table and reduce municipal water demand. ⠀
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The water is directed two ways using natural slopes and site contours to a well on one side and to a soak pit on the other side. To further enhance our goal, we have ensured that no hard scape is used and instead used soft scape that is permeable and allows for water to seep through directly into the ground.

Openings, Light and Ventilation:

The building footprint at Navovado is oriented to capture daylight as well as breeze effectively throughout the day. The openings in each space are designed generously to go above and beyond the minimum percentages required for fenestrations. This results in naturally well lit indoor - outdoor spaces which do not require any artificial lighting in the daytime and therefore cut down on energy expenditure. The openings also allow for continuous air circulation with ample cross ventilation in every part of the structure.⠀

Some of the other innovative material uses that we have tested in Navovado to maximize our sustainability efforts:

• Reuse construction debris to fill under plinth instead of virgin stone rubble.

• Reuse the cut-waste from stone flooring for new flooring

• Use fly ash bricks (with upto 93% recycled content) and slag cement (with upto 65% recycled content) for our super structure

• Use true terracotta mangalore tiles for roofing that ranks high on the solar reflectivity index

What is a green building?

A green building is one where you’re trying to reduce the impact of the construction on the environment. It is about making the right choices at every stage and  looking at every possible way, to optimise resources during and post construction and to minimise or offset one’s footprint right from the design stage to the occupancy stage. Right from positioning the building on the site, being mindful of the solar and wind orientation, looking at the existing resources on site to incorporate them into the building, preserving the underground water table - the environment is part of the design criteria from the very first step of the design process.

Here are some tips for an architect to design a green building

• The building should be designed for its local climate and weather

• The design should be site specific

• The natural features on the site must be preserved whether it is the trees, the underground water table, the contours and terrain, etc

• Plan openings for maximised daylight and cross ventilation

• Reduce the urban heat island effect 

• For landscaping, use lesser amounts of non permeable surfaces like concrete and more permeable surfaces like grass that allow water to percolate and recharge the underground water table

• Reduce concrete exposure because concrete tends to absorb a lot of heat

• Enhance thermal comfort by thinking about all parts of the envelope - the walls, the windows, the shading devices, the roof, etc - to reduce energy expenditure

• Conserve water and collect or harvest rainwater

• Use aerators for taps and dual flushes for WC

• Use solar water heaters

• Use solar panels if the site allows for it

• Compost using house and site waste and feed it back to the garden

• Reduce, Reuse, Recycle

Every little detail helps.

Links to our previous Blog Posts on Green Building:

• GREEN CERTIFICATION

• WHY BUILD GREEN

• GREAT ONLINE RESOURCES FOR GREEN BUILDING

• GREEN FEATURES AT NIVIM