Celebrating Navovado, our design-build vacation house in the Goan countryside through a gallery of photographs of the courtyard house. Earlier this year, Navovado won the prestigious Platinum Certification from the Indian Green Building Council. Navovado harvests all of its roof rainwater and recharges the water well on site. The use of low-flow water fixtures further improves water efficiency. Focus on use of insulation on the roof, double-glazed glass, low­energy use appliances, LED lighting and 100% hot water from Solar power makes this home extremely energy efficient. The structure is constructed using locally manufactured materials and materials with a high recycled content such as Laterite stone, Matti wood, Fly-ash brick and Slag cement. The garden is planted using native local species to reduce water use for ir­rigation. Finally, large openings allow for maximum daylighting and cross-ventilation, reducing the energy use for lighting and cooling.

The heart of the home lies in the large central courtyard that is an extension of the kitchen, living and dining space. The courtyard houses the swimming pool and provides a green private space to be enjoyed by all the residents of the house. The courtyard morphs in its use depending on the time of day and occasion. The guest bedrooms on the ground floor are designed as pavilions on either side of the courtyard, while the first-floor bedrooms have a large terrace overlooking the courtyard that connects the two levels.

Find Navovado featured in detail on our Instagram page here.

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I was invited by Architecture + Design magazine to discuss Green Architecture, its nuances, realities and myths.

It is pertinent now more than ever to create buildings with minimal architectural intrusion and the conservation of natural resources. In this session, I speak about conscious architecture based in context and the little steps that we can take in our pursuit for ecological balance and sustainability.

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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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

We are elated to present to you pre-final photos of Nivim Goa from last month.

CLICK ON LINK for fullscreen photos.

Be sure to click on the 'fullscreen' icon on bottom right. 

Shot in April, these photos show the house just before the final finishing stage. We began construction on the house end of January 2011. The core principles of the house is to promote architectural excellence and environmental sustainability.

We are now about 2-3 months away from finishing. We are aiming for the 'Gold' level green homes certification from the Indian Green Building Council and will be the first home in Goa to be certified. Read more on the green initiatives at Nivim Goa.

As for architectural excellence, we have attempted to create spaces that are inspiring, use natural materials and design building openings that all together enhance the user's relationship with the environment. Read about our design concept.

The photos above give the feel for the raw architectural space and materials, and show the bare building that is not hiding behind any fancy finishes or landscaping.... Do see the pictures and we will let you be the judge of how far we have succeeded in achieving our goals.

See all the design and construction updates for Nivim Goa.

All photos courtesy Sanjeet Wahi, Photographer, Delhi.

We recently crossed another project milestone by completing the first design stage documentation towards the Green Homes certification awarded by the Indian Green Building Council

We are targeting the gold level certification and will be among the first green certified homes in Goa.

Some of Nivim's main green features are listed below. We will try to do detailed write-ups on some of these in future posts.

Trees and preserving site’s unique features

– Our project site had 14 existing trees before construction and we preserved these trees and incorporated them in our design. The design also retains nearly 35-40% of the site as natural landscape. New landscape is planted with majority local species to have minimal need for irrigation water use.

Building orientation and design

– The main house building is oriented with the longer façade facing North-South to minimize direct sun exposure on east and west where the sun is lower increasing heat absorption. Ample shading devices have been planned to further reduce sun exposure and heat intake.

Daylighting and cross ventilation

 – 100% of living spaces are designed to be adequately day lit with ample shading and openings for cross ventilation. This eliminates the need for any artificial lighting or mechanical cooling during the day saving energy use and providing healthy indoor air quality.

Energy

 – 100% use of solar power for water heating. Use of 3-star energy efficient refrigerator (40%less energy use) and 5-star rated air-conditioners (25% less energy use). Use of solar control glass on east and west façade to reduce heat absorption to indoors.

Cool Roof

– 75% of roof is finished with highly reflected material to reflect sun’s heat thus help in maintaining lower temperature in living areas below.

Two openable walls per room provides 100% daylighting and cross ventilation

Water

 – We are collecting 50% of rainwater runoff from the roof and storing it for future use for landscaping and for swimming pool use. Prioritized use of low-flow fixtures in the bathrooms saving 30% of water without having any impact on perceived flow of water and use. We are treating 100% of our grey water* on-site to be used for landscaping thus further reducing pressure on municipal water resources.

* Grey water is all water from bathrooms and kitchen drainage except water from the toilets. Grey water is filtered on-site through a root zone water treatment system.

Permeable paving

– 75% of site’s paved surfaces are built using permeable paving to allow maximum percolation of rain water back into the ground.

Construction Materials

– Use of over 50% building material from within 500kms of the site to reduce embodied energy spent in transporting materials over long distances. Encouraged reuse of salvaged building material as well as building material with high recycled content such as fly-ash bricks, fly-ash cement, recycled tetrapak boards, aluminum and reclaimed wood. Reducing the use of cement** in construction by building load bearing walls and filler slabs. 

**Cement production is known to produce large quantities of greenhouse gases, for every ton of cement produced one ton of GHGs are released in the atmosphere. GHGs are known to be the leading cause for climate change. Read more here.

Low VOC paints

–Use of low VOC external and internal paint to reduce exposure to hazardouschemicals to humans.

List of green certified buildings in India, http://www.igbc.in/site/igbc/certifiedbuilding.jsp

I was recently interviewed by National Geographic for their upcoming documentary on Green Buildings in India. The following was my response to them and it lists my views in a nutshell on the topic. I hope I do not sound too angry, disappointed or disgruntled... the truth of the matter is that we have a long way to go to make green buildings as mainstream commercial and day-to-day construction practice in India today.

_________________________________________________________

Dear Mr. Producer

Thank you for your email. I am an IGBC accredited professional in India and a LEED accredited professional in the US. I am architect and have been working in the design and construction industry in New York for many years.

For the last year and a half, I have been busy in building the first green certified home in Goa. We are aiming for the Gold IGBC Green Homes certification. What makes the project unique is that we have considered and employed strategies from the three green ideologies that exist in India today:

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The age old traditional common sense building principles such as building orientation, retaining existing trees and building around them, courtyard plan, load bearing walls, etc.

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The alternative building strategies such as filler slabs, reducing use of cement, prioritizing use of existing material on-site, recycle and reuse of wastewater, etc.

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The new cutting edge technologies such as solar water heater, environment-friendly HVAC systems, moisture sensors, electric sensors, electric vehicles, low VOC paints, green roof, etc.

Unfortunately in India today these three streams of sustainability exist in individual silos and are not really working together. Everyone seems to be doing their own thing while commercial developers have joined the green building bandwagon only as eyewash to improve marketability and sales

The biggest challenges to green buildings in India are the vast regional climatic variations, perceived high cost, lack of usable information, material procurement, labor training, lax regulatory environment, lack of incentives and lack of education on the need for green building among contractors, building material manufacturers, vendors and the final consumers.

Organizations such as IGBC, TERI and CSE have done a good job of educating and training the architecture community. There is also awareness among the global material manufacturers and suppliers. But sadly, there is still long way to go when it comes to training the remaining regional/ local participants of the construction industry. It would actually be fun if you walk through a local building materials market in your city and simply ask the vendors and buyers ‘what is green building’. This could result in an amusing montage on the state of green building in India and how far we still have to go.

We are building in a small state of Goa and have faced challenges in procuring items as simple as low-flow water fixtures. We are now accustomed to receiving blank stares from vendors, public officials and neighboring community at the mention of the word ‘Green Building’. An interesting anecdote is my conversation with my neighbor who was shocked at our plan to construct recharge pits to percolate rain water back into the earth. Her state of utter shock (and some extent distrust) stemmed from the fact that she could not comprehend why we would spend money on something that did not give us anything back. When I explained that sometimes actions need to be based on the larger common good and not only immediate personal gain, I was honored with the same blank stare…

It is surprising that in a state with a high percentage green cover, a rich agrarian culture, low population and density, the residents frequently complain about lack of adequate water supply. Goa is a coastal state and receives a very high amount of 3metres in rainfall every year. Still the water table around our site has been dropping over the years. The same neighbor as above attempted to dig a well in their property many years back and did not find water at decent depth. The obvious problem is that we are using resources at a much faster pace than the earth can replenish. This problem is of course much more pressing in cities but it is a shame when you find it in the seemingly green paradise of Goa. As with the rest of India, Goa is experiencing a building boom. The responsibility of builders to preserve this fragile remaining slice of extremely biodiverse and sensitive environment is extremely critical.

Green building is responsible building. Among global consumption of resources, buildings account for: 20% of water use; 25-40% of energy use; 30-40% of solid waste generation; 30-40% GHG emissions; and 40% of use of raw materials. While building anything, even a tiny house, one must understand that we are utilizing material, energy and water in construction, and changing the ecology of the site and surroundings forever. Plus, we are adding to the demand for resources for as long as the life of the building.

Another favorite statistic that should be a wake-up call to the current mainstream building practices in India is that the production of Portland cement accounts for 5 - 8% of global greenhouse gas (GHG) emissions, the major cause of climate change. The high emissions are due to the chemical process that produces cement and as a by-product generates large amounts of carbon dioxide. One ton of GHG is released with every one ton of cement production. These figures are shocking and must be considered while thoughtless construction of concrete frame-structure building and hardscaping of open areas.

I have added brief notes to your questionnaire. Your show can go a long way in educating the common man about the need and benefits of building green. I hope that you will attempt to dig deep into the subject. I wish you best for your project.

I am adding some biographical information about myself below. For more information on our project in Goa, you can visit:

http://www.newyorkgoadiaries.com/

http://www.newyorkgoadiaries.com/search/label/Green%20Building

Best

Anjali

View of the entrance courtyard, part of deck and pool pavilion

We have a small milestone to celebrate this week. We are completing 32 weeks into construction at our project site. With a projected total of 12-14 months as our construction timeline, we are close to the 60% milestone. The real reason to celebrate is that we have completed 60% of construction on-site and are almost on-track to finish within our projected schedule. For anyone who has built in India, this is quite a considerable feat. Projects in India are ridden with unexpected and often unexplained delays mainly due to the unorganized construction industry, loose legal frameworks and maybe skewed priorities among builders and contractors. While design is all glamorous and intellectual, the construction process is where one needs to get down and dirty with all kinds of details of sourcing the right materials, controlling quality on-site, meeting deadlines and coordinating with the various professionals involved. Our team deserves a lot of credit, they are working hard and have a common unique trait (that is central to our hiring process but sadly not that easy to find), they all "take pride in their work".

Last month, we had the privilege of a visit from two prominent architects from Delhi to our site. They left with two comments. First - "Finishing a project in India in 12 months is only possible if it is regular building, it is very difficult to finish a project in that time while building the way you are building". I guess they were referring to our load bearing stone wall structure that require much longer to build than a typical concrete structure, plus the large size of our rooms with high ceilings and possibly to the fact that we have very large openings and not little pigeon hole windows and doors. Their second comment was, "If the talent exists then how come we do not see buildings in Goa built in even half as conscientious manner as you are building." This is the best compliment we have received so far and I was joyous to hear this observation.

At our 60% milestone, we have completed nearly 90% of our civil works, electrical and internal plaster. Civil works for external landscaping is almost 50% complete. We are now busying ourselves with the internal and external door frames, plumbing and flooring.

Sketch rendering of our elevations and opening design

Since, we keep talking about our extra large openings, it is clearly evident that they are critical to our design proposition. We have gone back to our drawing boards many times in order to perfect the design of the fixed and movable doors and windows. The final design looks like the rendering above. All openings will comprise of fixed glass windows on top with wood louvers and movable sliding door panels below. The movable panels will all have a fixed shutter on one corner with wood louvers. All the remaining sliding doors when opened will stack behind this fixed frame. The louvers are designed such that they provide an interesting play of light and shadow within the room at different times of day. Louvers reduce direct sunlight and glare into the rooms. On the other hand, louvers also reduce the visibility to the outside. Keeping this in mind, the openings have been carefully designed with a balance of louvered panels and ones with clear glass.

Sample of a fixed louvered section of the opening built on-site for review

Another interesting functional design feature in our external opening design is that the fixed louver panels will actually be fitted with mosquito nets and have a sliding glass door behind them. This is our proposed solution after various design iterations to address the following conflicting factors that influence living in Goa:

- the ability to keep the doors open for as long as one can to connect with nature

- the insurgence of mosquitoes at dusk specially during monsoons

- the ability to allow for cross ventilation at all times of day even when there are mosquitoes, or if it is raining, or for any other reason the doors need to be kept closed

- the need to make the space air-tight if the use of mechanical air-conditioning is needed

Attention to details such as this comes only from living in a place through the seasons to know peculiarities in climate and livability. Trust me, I wish I had mosquito nets in the openings in my house that allowed cross ventilation, did not block my view, were easy to clean, not stuck with velcro, did not obstruct my ability to open and close my windows and most importantly kept the mosquitoes out but the breeze in.

Another key success of adding nets to the openings is enabling cross ventilation at all times and reducing the need for mechanical air-conditioning at all times of the day throughout the year. This reduces the energy requirement of the house and the pressure of added development on the land.

As a result of our opening design, 100% of our living spaces are daylit. This is based on the math that shows that 100% of our living area has a daylight factor of at least 2%. (Daylight Factor = Window Area/ Floor Area X Actual Visible Transmittance X Constant)

In addition, 100% of our living spaces have access to fresh air ventilation. This calculation is based on the area of openable windows as a proportion of the living area of each room.

Both these statistics far exceed the standards for Indoor Air Quality as mandated by leading green guidelines as being critical to healthy living.

So far so good. looking forward to more happy discoveries and experiments in the remaining 40%. 

So much is happening on-site that I do not know where to begin our update. Fortunately, our contractors are good at multi-tasking and can execute separate items of work simultaneously.

An important milestone last week was the completion of all the major planned concrete work on-site. The last item on the list was a small roof slab for the pump room located below the deck. This therefore seems to be an appropriate time for us to talk about the use of concrete in our project.

As I mentioned in my last post, we have tried to reduce the use of concrete to the minimum in our project. The reason is the inherent negative environmental impact of cement use. The production of Portland cement is known to account for 5 - 8% of global greenhouse gas (GHG) emissions which are the major cause of climate change. The high emissions are due to the chemical process that produces cement and as a by-product generates large amounts of carbon dioxide. There is little that can be changed in the cement producing chemical process and hence the resulting emissions. This puts the cement industry at the forefront of global environmental and climate change debate. Link to a NYTimes article on the topic.

View of the living room with 40cm wide basalt load bearing walls and two corner columns to allow for extra-large front and back openings

In India, most buildings are built with a structural frame of concrete beams and columns. After this, the walls are filed in with brick or other building blocks. In our mission to reduce the amount of cement use, we decided very early on to design our structure with load bearing walls.This strategy is more feasible (and actually the more obvious and practical solution) for a building like ours that is mostly built on the ground plus one floor (as a result the primary load on the structure is the roof and not multiple floors above). All our external walls are built with basalt or laterite stone, both locally sourced natural materials that take the weight of the structure above. The only need for concrete columns, total six in number, was to allow for the extra large openings designed in all our rooms.

As a second step, we decided to use fly-ash cement in place of regular Portland cement in our concrete mixes. Fly-ash cement is sometimes called green cement as it replaces between 15-25% of cement with fly-ash. Fly-ash is the by-product from burning coal. Therefore, fly-ash cement reuses industrial waste. The performance of fly-ash cement is also completely structurally safe, as it must follow the national codes for design and construction of concrete, as per IS codes 456-2000. In addition, fly-ash in concrete is known to improve the long-term strength of concrete, reduce corrosion and permeability. Here is some more reading material on Fly-ash cement.

After using fly-ash cement in our concrete mixes, the only difference that we found is that a fly-ash concrete mix takes slightly longer to set, so contractors prefer to use the quick drying Portland cement. Other than that the performance and workability has been comparable to regular Portland cement.

While laying the RCC slabs using filler blocks and fly-ash cement

Another construction innovation employed by us in our quest to reduce the amount of cement used in the project was the use of filler slabs in place of conventional reinforced concrete (RCC) slabs. The science behind filler slabs allows for a replacement of up to 30% concrete in a RCC roof slab with lightweight filler and non-structural material such as bricks, tiles or earthenware. The idea is that in a RCC slab, the upper part is subjected to compressive forces while the lower part experiences tensile forces. The concrete in RCC is good at supporting compressive forces and steel good at tensile strength. Hence, there is no structural need for concrete in the lower part of an RCC slab. As a result, the gaps between steel reinforcement can be filled in with lighter material (even waste material such as bottles, old roof tiles or broken bricks). Filler slabs also contribute in reducing the load of the slab itself therefore reducing the amount of weight that falls on the vertical structural members (load bearing walls, or columns) and foundations. Read more about filler slabs.

For use as filler material in our project, we made simple mud blocks on site from the earth excavated from foundations. These blocks were sun-dried. As a result, we used no new material or spent any additional energy in making them or transporting them to site.

Filler blocks made with excavated earth from site being sun-dried

Filler blocks that were made on-site ready to be used

View of filler slab from below after removing the shuttering

In our experience, a big deterrent against the reduction of concrete in building construction is the unwillingness of structural engineers to work with any structural solutions other than the conventional concrete frame structure. The calculation models used by structural engineers don’t seem to be designed to incorporate load bearing capacity of walls and reduction of the slab’s weight by using lightweight filler material. Along with creative architects, the building industry also desperately needs creative engineers who understand the long-term implications of their work and input on the environment.

Finally, I guess the follow-up question is why more people are not building with load bearing walls, fly-ash cement and filler slabs. The only reason that comes to my mind is the inertia to adopt new ideas or perhaps laziness. The building industry fails to educate their clients and together adopt obvious and simple steps towards building a greener building, reducing the pressure on existing resources and ensure the long-term sustainability of our planet.

View of the river and hills from the living room terrace

It is the month of July and we are right in the middle of monsoons in Goa. Monsoons in Goa bring with it torrential rains with gusty winds that sometimes continue for days without interruption. Most people agree that monsoon is the best time to be in Goa. Everything gets covered with a carpet of green. Plants grow several inches as if they were fed by artificial growth hormones. The sights and sounds of Goa in the monsoons are therapeutic in the most natural way.

Now let me tell you how it feels on our project site when it rains. First, you hear the rain approaching from a distance, rushing towards you. You see in a distance that the hills begin to blur from view. Then you can hear it above you but you miraculously remain dry due to thick tree cover. Finally, you start to feel a light spray of water that is escaping through the leaves. That is when you smile to yourself and decide whether to dash indoors for shelter or in the open to join in the fun...

From that romantic vision, let us turn our attention back to matters of construction, matters concerning brick, mortar and cement. As I explained in our last post, with the rains in full swing we are concentrating our energies to completing interior construction jobs. Last week on site, we completed the construction of internal partition walls in the main house. The material we have chosen for the internal walls is fly-ash bricks.

Fly-ash bricks being delivered to site

Fly-ash bricks are made with fly-ash that is a waste product from burning coal in power plants and sponge iron plants. This fly-ash when mixed with gypsum, lime (both also industrial waste products) and sand can be used to produce a viable building material in the form of fly-ash bricks. As a result, fly-ash bricks constitute 75% post industrial recycled material by weight. The performance properties of fly-ash bricks are also known to be comparable and in some cases better than regular brick, with high compressive strength, low water absorption, good thermal and sound insulation and no efflorescence.

The advantages of using fly-ash bricks are:

1. Recycling an industrial waste product for a new viable use. Fly-ash otherwise if not properly disposed is responsible for increasing air-pollution, making arable land infertile and contaminating water bodies.

2. Manufacturing of fly-ash bricks does not require firing. Fly-ash bricks are either sun-dried or steam dried. This eliminates the high energy use during the firing of regular bricks.

3. Reduces the need to quarry natural stone.

4. Fly-ash bricks are made locally in Goa about 50 kms. from our project site, reducing the embodied energy used in the transportation of the material to project site.

(Source for some of the above materials is an article written by Tallulah D'Silva on Fly-ash Bricks for Business Goa magazine, April Edition.)

Along, with fly-ash bricks, we have also chosen to use fly-ash cement in construction instead of regular Portland cement. It is not very well known but the production of Portland cement accounts for around 5% of global greenhouse gas (GHGs) emissions. It is estimated that the production of one ton of Portland cement produces about one ton of GHGs. Look out for more details in future posts on our use of fly-ash cement, load bearing walls and filler slabs in our effort to reduce the use of cement and concrete in this building.

Building partition walls with fly-ash bricks