Glaring mistakes

conventional v/s curtain wall

In hot climates, the overall energy usage rises as you increase the glazed area. Curtain walls, therefore, are highly inappropriate.

I have ranted about glass façades for a long time and this editorial by Sunita Narain of DTE has inspired me to add a couple of paragraphs to the original one.  Among other things, she has written about a recent study by IIT-Delhi which found that, in our hot climate, the manufacturers’ claims of special coated glass or double/triple glazing being able to reduce heat gain are rather hollow.

One of the other specious arguments put forth in an attempt to portray glass curtain walls as green systems is to say that it reduces the electricity consumed for lighting. This is a half-truth. Leave aside the uncomfortable glare that people working inside such buildings have to put up with, let us make a simple comparison.

Consider a 10m² conventionally designed space. Assuming that we don’t take passive cooling techniques into account, the air-conditioning load will be in the region of 3,500W (1 ton).  Lighting the same space, on the other hand, will need just 50W with fluorescents or 40W if we’re using LED fittings.

Now, imagine a similar sized curtain-walled space. The maximum saving that can be achieved by reducing lighting is a puny 50W. However–and this is the big problem–air-conditioning requirements will probably have risen to a whopping 5,000W.  Even with all the specially coated and multi-layered of glass in the world, the total requirement is unlikely to be anything less than 4,500W.

So yes, we may not use as much electricity for lighting but, I’m afraid, the energy usage for cooling will go right through the roof and no amount of marketing spin can get around this simple fact.

Building walls with the rat trap bond

Just in case I’ve got you visualising rodents scurrying about where they’re not wanted, ease your mind; the rat trap bond I’m talking about is simply a method of laying bricks when building a wall.  It’s similar to the common “Flemish” bond but instead of putting the bricks on their face, they are placed on their edges. This leads to cost savings because less bricks and cement are needed which, in turn, reduces the embodied energy of the wall.

The Rat Trap Bond

Bricks are laid on edge to create an air gap between two layers

Laurie Baker took every opportunity to try and make people realise the value of this method but, by and large, the 20-25% saving in brick doesn’t seem to have been appealing enough.  The rat trap method of construction was popular in England until the start of the 20th century but sustained lobbying by the brick-making industry convinced people that that it was not strong enough to build load-bearing walls.

That is rubbish of course; it’s strong enough for one and two storey buildings as has been proven over and over again by Laurie Baker’s lasting work. But masons too are not usually happy about adopting this system and come up with all sorts of excuses to try and avoid it. I have to admit that, till date, I have not pushed hard enough against their inertia but now I’ve just got one more reason to do so.

For the ShKo bungalow at Karjat, I plan to use the rat trap walls and wanted to know just how much difference they would make thermally. Nobody seems to have done a calculation of the difference — at least there was none that I could find. So, armed with some data from thermal calc and the energy evaluation component of ArchiCAD, I tried to do just that.

Taking just a simple 3m x 3m structure with no openings, I ran a calculation for both types of wall. Result: average U-value of the structure’s outer shell dropped about 15% compared to conventional walls and the energy required for cooling also fell by about 8%. The difference was exaggerated because the model had good roof overhangs to shade the walls.

Still, when you think about it, 8% is nothing to scoff at.  In addition, the embodied energy is reduced quite dramatically and, of course, Laurie Baker’s original reason for using the rat-trap bond still stands — the wall is simply cheaper to build.

Now, I just have to go and steam-roll the masons into learning a new technique.

The Architect and the Plantsman

This Wall Street Journal article on the collaboration between reclusive Swiss architect Peter Zumthor and ascetic Dutch landscaper Piet Oudolf made me think about my own (much less famous) interaction with A.Y. Retiwalla for the Karjat Resort a decade ago. Unlike the collaborators here, neither of us had heard of the other before and were brought together by the client, Dr. Beramji. Still, the mutual respect and acceptance of ideas was similar and it ultimately led to something that was appreciated by all.

The restaurant, shortly after construction

The restaurant, shortly after construction

The restaurant about five years later

The restaurant about five years later

No egos were bruised during our meetings — they were left outside

Mr. Retiwalla was already well established in his line and it is to his credit that he discussed things with a relative youngster like myself, purely on merit. Ideas flowed freely between us and, with Dr. Beramji taking a keen interest in every aspect of the project, the tripartite meetings were very enjoyable.

Designing for Noise

designing for noiseAs Queen’s 1980s song, Radio Ga Ga, laments, “we hardly need to use our ears“.  Actually, we abuse our ears or, at the very least, ignore the abuse that others heap upon them.

Unfortunately, while we are easily able to close our eyes, nature hasn’t equipped us with lids to effectively shut our ears.

But what does architecture and design have to do with all this?

Usually, unless an architect is designing something with an overt acoustic requirement like, say, an auditorium or a recording studio, only visual aesthetics are considered.  However, as Julian Treasure points out in this TED talk, the auditory aspect is more crucial than we realise.

He illustrates just how detrimental the effects of noise can be, not only in special environments like hospitals or schools, but in homes and offices as well.  For myself–even though I’m quite aware of the debilitating effects of loud noise–the talk was quite an eye-opener.

See the video on TED | Why architects need to use their ears

ShKo Bungalow at Karjat

The design for the ShKo bungalow at Karjat has finally been completed. It’s taken a lot longer than most because, apart from the complex slope, there was a severe constraint of building within a small portion of the entire one acre plot — the rest is prone to occasional flooding from the adjoining river.

Like other architectural designs, this too makes maximum use of local materials and of passive cooling.  External stone walls are at least 24″ (60cm) thick and provide a formidable barrier to heat-gain even in a place like Karjat.  Deep verandahs on the South and West don’t allow direct egress of strong sunlight from mid-mornings till evening. And high roofs with openings at upper levels allow constant ventilation to take place.

Rainwater harvested from the roof will be collected in the basement that is automatically formed by the sloping land. It will also be used to flood the pool which will not, hopefully, have any chemicals used to disinfect it. The current plan is to do natural filtration but the eventual system will depend on getting a reliable and qualified consultant to carry this out.

Some Renderings

ShKo Bungalow at Karjat

Survey plan for the ShKo property

Survey plan for the ShKo property

Last week ended with a site visit to Nasrapur, Karjat. This is the fourth design in the same general location after the [RaBV], [BAli] and [LGEs] bungalows so I’m extremely familiar with the area and climate.  Part of this particular one-acre plot is prone to flooding during the monsoon, and the only portion that is safely outside the flood zone (even considering the massive downpour of 26th July 2005) is on a mound near the road.  On this rise stands the ruin of an old shed which I had seen earlier but was unable to explore properly because, until recently, it was overgrown with Mucuna pruriens — locally known as khaj khujri. This climbing shrub causes extreme itching on contact with young foliage or seed pods and I wasn’t about to take my chances.

View from the river side towards the mound where we will build

View from the river side towards the mound where we will build the ShKo Bungalow

Unlike other plots in this cooperative society, this particular site doesn’t have too many mango trees — mostly due to the flooding aspect. We intend to plant native trees such as Millettia pinnata or karanj which thrive in such conditions.

I am really looking forward to starting the design. Conceptually, I’m looking at a string of structures — some of them without walls — forming a sort of “C” shape around a water body.  The river, unfortunately, is too far away and not visible from the mound.  The mountains of Matheran and the Garbat plateau, though, give a splendid view to the West.

High-Rises and Sustainability

SkyscrapersReading an article in Architecture Week about the impact that urban towers have on the natural environment, got me sitting on one of my pet hobby-horses.

I have never been convinced by arguments that high-rises are better and more sustainable than low-to-medium height buildings. I suppose some people get a kick out of defying gravity by erecting very tall structures but that, to my mind, is pure hubris.  Even if we dismiss the recently publicised link between the building of skyscrapers and a bubble economy, I still say it doesn’t make sense — purely from the sustainability point of view.

It may sound anachronistic but the fact remains that living high above the ground makes you lose touch with it.

One of the favourite arguments by proponents of tall buildings is, that they free up open space by reducing the physical footprint of built-up areas  However, at least in the Indian urban context, this is a fantasy that all but the most delusional will reject. In Bombay (Mumbai) where I live and work, every single patch of land is covered to the maximum. What little is left open–because it is mandatory–soon gets swallowed up by parking.  There may be a token play area, swimming pool or jogging track, but blank expanses of unpaved space where children can play freely, are conspicuous by their absence.

The second argument in the urban context is: as land is scarce and expensive, having high-rises propels affordable housing. Bunkum! You don’t need to look beyond Tokyo, Singapore and Hong Kong to realise that cities with the most high-rises also have the most expensive property in the world.

The other favourite argument of the tall-buildings-are-good school of thought is that they reduce energy usage in comparison to low-rise sprawl. Unfortunately, data shows that the opposite is the case..While the energy cost of transportation will certainly be higher if people live in far-flung areas, the overall energy footprint of a high-rise dweller is far greater.

Tall buildings–especially those that have large parts clad in glass–need much greater cooling in a tropical climate like ours.

Why is this?

High-rises have a huge amount of embodied energy in their construction and materials. Adding to that, the energy cost for “lifting” people and water against gravity is constant and very high.  This more than compensates for the additional carbon footprint that a suburban dweller uses — especially if the suburban dweller is able to rely on public transport for the daily commute. Ninety five percent of this city’s citizens do exactly that.

And what about quality of life? Given a choice, families–especially those with young children–would invariably prefer a place where the young ones can grow up with enough place to play. But that is altogether another story.

Further Reading:


PSah Factory

For most projects, I not only design, but also execute the work. For this one, though, because of distance, I only did the former.

The clients, manufacturers of packaging material in Cuttack, Orissa, wanted to construct a factory that was not just functional but, to the greatest extent possible, a green building in all respects. The product they make is hardly environmentally friendly, so it was somewhat ironic, but they had a genuine desire to make a change for the better so I agreed to take the assignment.

Design Principles

Initial concept

The initial conceptual structure had clerestory windows on the north and curved roofs to take maximum advantage of prevailing winds

Initially, the structure was to be of a single story only so, had that remained the case, the factory might just have looked like a variation on a theme with north-light roof trusses and curved metal roofs instead of straight ones.

Instead, and as luck would have it, the clients decided that they needed at least one additional floor to house the lighter machinery. Land in this area–alongside the Mahanadi river–is expensive and it would do them no good to scatter multiple structures all over the 2 acre plot. That posed a problem for the design as the clerestory windows would be of no use to the lower floor — either for light or ventilation.

View of Factory from the North-West

North West corner of the factory. This was the final design based on which the factory was actually built. You will notice that windows facing North are twice as large as those pointing West.

So, to allow for the clerestory windows to be used by both floors, I thought to turn them sideways. Back at the drawing board, I realised that only allowing windows on the North and East would mean the interiors of the factory would be dark for much of the day — not to mention that natural ventilation would be nil. On the other hand, too much light from the South or West was not desirable and neither was a draft that could carry in dust particles.

So I reverted to an undulating form–a double wave form in fact–that not only softens the factory outline but also works better for ventilation. Here the smaller waves face the South and West and the bigger ones face the North and East.

View of the factory interior

A rendering of the factory interior shows how the light enters indirectly

Now, when light enters, it reflects off the inner side of the baffle walls. Any heat that is generated remains in the immediate vicinity of the windows. Additionally, the upper of the two windows is bottom-hung to allow hot air to easily escape.

Between successive waves in the baffle walls, horizontal awnings protect the more conventional windows from the sun during the hottest times of the day.  In fact, sun-studies were carried out to ensure that the sun’s rays almost never directly reach the building’s interiors between 10:00am & 3:00pm.


Factory under construction

A view of the factory under construction shows the flyash bricks used for the walls.

Being a large structure which needs to take heavy loading, the framework and slabs had necessarily to be in RCC — a material that I avoid using when it is not required.

All the walls, including those of the baffles were from flyash brick and plastered only where necessary. Initially, we wanted to use the local laterite but that worked out much too expensive.


Some more photos of the construction

SVAGRIHA – a simplified version of the GRIHA Green Rating System

They’re calling it “Small, Versatile, Affordable” GRIHA – a less complicated green rating system for projects less than 2500 sqm. in area.   Quoting from the email they sent me:

ADaRSH (Association for Development & Research of Sustainable Habitats) is pleased to announce the launch of

Small Versatile Affordable Green Rating for Integrated Habitat Assessment

A Rating system for small homes, offices and commercial buildings with built-up area less than 2500sqm

SVAGRIHA is a significantly simplified, faster, easier and more affordable rating system and will eventually function as a design-cum-rating tool. It was required that attention be paid to smaller buildings in India which although have small individual environmental footprints but their cumulative effect is far bigger. SVAGRIHA has been designed as an extension of GRIHA and has been specifically developed for projects with built-up area less than 2500sqm. SVAGRIHA can help in design and evaluation of individual residences, small offices and commercial buildings. The rating comprises of only 14 criteria (instead of 34 of GRIHA) and the interface comprises of simplified calculators. These calculators can be filled using information from construction drawings like areas and quantities of materials. This can be done easily by the architect of the project. Once completed, the tool will tell the consultant the number of points that they are able to achieve in that particular criterion and provide recommendations for any improvements in order to improve the environmental performance of the building.

Process of SVAGRIHA Rating

  • Registration of project with ADaRSH
  • Submission of completed calculators, drawings and other documents as required (quantity estimates) to ADaRSH
  • Assessment/Review as per SVAGRIHA
  • Site Visit and due diligence check post construction (mandatory)
  • Evaluation by GRIHA certified Evaluator
  • Award of Rating.

Note: The site audit to check compliance will be done once the project is complete and all equipment to be verified are installed.

For more information please visit

GRIHA is the national green rating system for India developed by TERI and the Indian Government. I’ve always felt that GRIHA is far more suitable for us than (the more popular & better known) LEED rating system.

SVAGRIHA has just 14 criteria compared to GRIHA’s 34 and can act as a good checklist at the design stage.

SVAGRIHA CriteriaSVAGRIHA point groupsLooking at the point groups, I’m happy to note the weight given to Energy and Water conservation. At the same time, to achieve a rating, the design must achieve minimum standards in all categories. So while they say that 25 our of 50 points will give you a one star rating, adding up all the minimums means you actually need at least 28 points.  And finally, the table below shows the star rating that can be achieved.


Planting for Birds & Butterflies

Plants that you should consider

There are a number of things you can do to attract butterflies and birds to your garden. Here is a basic list that may be useful as a starting point for people living in peninsular India. Please remember that this list is neither complete nor comprehensive because habitats vary so dramatically across our country. I’ve tried as far as possible to list local species but some, like the Lantana, have naturalised in our country and have therefore found a mention.


A number of butterfly species lay their eggs on grasses – but not of the cultivated kind. Unless you have a very large plot, it is unlikely you’d want to allow these to grow. However, if the possibility exists, it is nice to let a patch of garden in a corner somewhere actually grow wild.
Bamboos are food for some butterfly species and refuge for many birds and other creatures. Keep them a little distant from your house if you’re petrified of snakes, though.

Shrubs and Creepers


Even if you live in the heart of a city like Mumbai, you will be surprised by the variety of birds you can see if there is enough greenery around. I’ve seen the beautiful Paradise Flycatcher in Breach Candy which is, barring a couple of tiny green pockets, as concrete a jungle as you can get.

Although the links above all point to wikipedia, a very good resource I have found for Indian plants is Flowers of India. The site aims at having comprehensive information about Indian flowering plants with their common names (especially in Indian languages), pictures and details of habitat and distribution.