The Initiative for Green Habitats represents a long term commitment towards providing solutions for the creation of Sustainable Built Environments. This blog attempts to provide an insight to our views, commentaries on our work, ideas that we are working on, and provoke thought where there are more questions than answers.

Thursday, May 19, 2011

House 3: Friends of Camphill- India, Bangalore

Proposed House 3 at 'Friends of Camphill'
A residential facility for persons with special needs, Friends of Camphill India, FoCI- is an institution that believes in providing its differently-abled residents a home like environment for leading a life of dignity and freedom. House 3 at Friends of Camphill India, FoCI was meant to be an addition to their existing campus at Bannerghatta Road which contained two houses and a central training cum workshop unit. The folks at FoCI knew fairly well what they wanted. The 'house parents' - the Aradhyas, set the tone for what was to come. After a rather interesting first meeting with them- during which they told us a little about the philosophy of 'social therapy' , their approach to community living with the special residents, initial impressions on what they hoped House 3 would come to be- we hit the drawing board to begin ideating on House 3. We felt a strong need to understand the special needs of these residents and therefore we began to read up literature and case studies on similar homes around the world.

What they wanted House 3 to be: A housing unit for about six residents complete with accommodation for the house parents (the people in charge of the running the house), co-workers (the ones that assisted the house parents), guests (family of the residents visiting them) along with the requisite ancillary facilities. The Aradhyas desired House 3 to be a secure, practical, simple, beautiful, durable and environmentally sensitive development.

What we began by doing:
The North East corner of the camphill site, where we chose to locate House 3
Identify the best location to site the new House 3 based on an analysis of the site: We found the site to be a green haven- comfortably remote and removed from the din of the city. We did not want to change this special quality of tranquility and peace that the campus already had. We therefore began by carefully examining the site, analysing its potentials and threats in terms of- topography, site drainage, climatic factors, vegetation & trees, water features, circulation and relation between existing buildings and many more such factors that would influence the ultimate siting of House 3. The site sloped from the south down towards the north west. The northern edge of the site was used for waste water treatment through a system of linear planted beds and sedimentation tanks. The north west corner- being the lowest portion of the site had a large well which was used for recharging ground water- from run-off storm water and the treated waste water- this in effect was the soaking zone of the site. We therefore had to restrict how close we could build to this soaking zone, keeping intact the water treatment beds on the north. It was concluded that House 3 be ideally located nearer to the North-Western portion of the site making it easily accessible to the existing road and creating least disturbance to the existing land form and vegetation.

Analysis of terrain, physical connects, no-go zones, etc.
Identify the strengths of the existing units and their functional organisation: Since we saw merit in the way the existing two houses functioned, we thought it prudent to identify aspects of design that were working favourably in the existing two homes. For eg: The sequence of spaces starting from the forecourt (in which the residents assembled during celebrations)-to verandah (the public private interface)- enclosed living (where the residents gathered daily for various activities)- semi covered court and finally the living quarters we thought served well in the functioning of the house.

The public entry court to House 3. On either side are the private courts.
Evolve a new organisation diagram: The location so chosen for House 3 did not allow for the inward looking square plan as of the previous two houses- thus in an attempt to conserve as many trees at site and adapt better to the topography there- we began to evolve a more open plan form that would be better suited.

Design intentions/ What we wanted House 3 to be: We wanted to carry forth the elements of design that we found working well in the older developments while creating a new building type specific for the current need. The residents who were to occupy House 3, we were told, were going to be either the elderly residents or those requiring additional physical care- perhaps wheel chair bound individuals too. We therefore felt the need to give them a sense of private space within the collective while providing for a multi-sensory experience throughout the home- making for an interesting world within a world. It was required to establish secure connections with the outdoors for these special residents and also create living spaces which would be safe for them and easy to monitor by their care givers.
Within one of the private internal courts
We also wanted to provide the residents with the option to personalize internal spaces by allowing for varying storage configurations. A variety of common and private gathering spaces for residents- both indoor and outdoor were also being planned.

What House 3 is: Simplicity of structure being a driver, we generated a grid that would accommodate the bed and storage units and included a seating alcove within each living unit. Building in this modularity ensured there would be flexibility in use as the occupants of these spaces, as we had seen in the existing two homes, liked to make their portion of the room that little bit more special- some created photo walls while others decorated niches.

The basic module flexible to combine into a larger space, and
of internal organisation.
What evolved thus was an open L shaped plan with two wings- one for the male and another for the female residents. At the intersection of these two wings were designed common facilities and the main entrance and at their free ends were bundled the toilet, bath and laundry spaces. The lower floor was to accommodate facilities for the residents and house parents while that of the co-workers (the support staff) and the guests (visiting families of the residents) were placed on the upper floor for the convenience of its users. The external edges of the two wings were treated differently owing to their orientation- the Northern wing had seating alcoves with windows facing due North, while that on the West was more carefully treated to keep out the harsh west sun and allow light mainly through the north and south sides with smaller openings for venting at an upper level on the west wall.

The Ground floor plan. The red space is the central dining and
prayer space. The floor above is similar, but for a clothes drying terrace
The central living area was conceived as a large volume multi activity space- accommodating configurations for daily dining, prayers, occasional meetings and gatherings of all the residents. Although the clients gave us the option of building closer to the well as they were open to the idea of relocating it; we decided to distance the building from the well on the north west corner- keeping intact the water recharge and soaking that naturally occurred there. This space, being central to House 3, allowed users to step out on to decks that over looked the north west corner affording glimpses of the setting sun.

The upper level, providing interaction spaces, seating zones, and
an engaging area away from the ground.
The built: The structure of House 3 was envisioned to have load bearing rammed earth walls with vaulted intermediate floors. The sloping roof was to be in lightweight ferrocement channels- a decision we took although the existing buildings on site had Mangalore tiled pitched roofs as the latter was, according to us, a higher embodied energy material. We were told in the first design review meeting that the general textures of this place could not be fragmented or appear to be so- as this the residents would find disturbing- so we replaced our prior recommendation of a Terrazzo floor with that of homogenous pigmented oxide floor. Rough stone for the toilets and a randomly patterned stone flooring for external courts was suggested. The walls were to be finished in lime and plaster rendered with natural lime and painted, where necessary, with non- toxic paints. All the joinery of House 3 was to be in reclaimed timber.
Working on the House 3 at FoCI was an enriching experience that gave us an up-close insight, albeit briefly, of the many complexities that people with multiple disabilities had to grapple with and the phenomenal courage, commitment and discipline that was required to keep a home such as this going. Design wise- it made us more committed to being sensitive to user requirements as they were so unique here and needed to be dealt with great care. We attempted in House3 to develop a built environment that not only responded well to its immediate context but also functionally satisfied the special needs of its users.

(PS: For more images of House 3- click here)

Monday, May 2, 2011

The Sustainable Housing Complex for ACC

Sometimes, even the biggest giants surprise you.
ACC, one of India's super brands and the oldest cement company had set a mandate of going green. Over the last years substantial changes from their composition of cement, to the manufacturing process, and even the way they built their own corporate office were initiated. The mantra in their plants was non-polluting and the greater production of pozzolonic cement. For their buildings were set the goals to achieve the highest standards of green building practices.
Along these lines, ACC had initiated the process of building their entire residential campus for their staff colony of their cement grinding plant at Kudithini, in Bellary, Karnataka, as a sustainable campus. M/s Ashok B Lall Architects, ABLA, from Delhi were roped in as the main Architects for this project. Mr Lall's office went about putting together the remaining team for the project (services consultants, energy consultants, LEED/GRIHA certifcation consultants, Landscape consultants, and last but not the least, the Construction Management Consultants. That is where we (IGH) came in.
As construction management consultants, we had the task of enabling, coordinating and managing the various outcomes of the various consultants. To boot, our programme was by our design, carried out as 'Sustainable Construction Management Consultancy'. By this definition, we took up cudgels on the behalf of the architects to ensure that the entire development, its building construction systems and methods employed would be resource efficient and therefore occupy a low ecological footprint.
The ACC Greens Village, as it was later named, occupied the western section of the larger 240 odd acre campus of the Kudithini cement grinding plant. Area for this campus was demarcated and occupied about 50 acres in all. Going beyond the mandate of designing and building residential quarters and some amenities (amounting to some 83,000 sft), this Village of sorts also incorporated into the brief
  • a huge afforestation programme,
  • food sustainability- which saw the development of a sizable farm, a cattle shed (for milk) and a fish pond
  • rainwater management, harvesting and recharge,
  • energy sustainability which saw the incorporation of biomass gassification infrastructure, supplement by woody biomass from the afforestation programme, and a bio-methanisation unit supplement by the dung from the cattle shed.
Our engagement on this project can be highlighted in these following sections:
Development of a prototype structure
The first part of our involvement as a member of this team saw the suggestion of building a prototype structure that would embody all the construction systems envisaged and also serve as a benchmark of quality for the remaining construction to follow. This would also have ensured that all obstacles and hiccups (design or execution) would be limited to just this structure, with smooth sailing on the larger project.
An alternative to RCC slabs
Mr Lall's office had designed some exquisite buildings that were based on solar passive design principles and were based on an innovate thermal management of the interior spaces through cooling tubes, insulation and aided hydration for those hotter months. Essentially, the building type can be described as being sandwiched between cooling tubes to the east and west, and verandahs to the north and south. The cooling tubes had a wind scoop from the northwest and an exhaust side towards the southeast. The verandahs had openable insulated screens that would remain shut during the hotter months (trapping air which would retard any heat exchange) and be kept open for the more cooler months.
One feature designed originally by the ABLA was to pass cool air from the cooling tubes through the slabs of the building, therefore resulting in a deeper RCC slab and with PVC pipes as passages to this air. We suggested an alternative- a pre-cast system, which involved the placing of semi cast latticed RCC rafters and hollow pre-cast blocks that were cast to fit the needed profile. This system involved the usage of lesser concrete than the RCC slab originally suggested, and also meant the reduction in the usage of steel in the slab. One added advantage was the doing away of any shuttering for the in-situ pouring of concrete. Another was quality control. After scrutiny of the system and a visit to a vendor's site, the architects were convinced and the system was chosen.
The rafters were latticed t-beams, and were semi-cast (2 inches of the base was cast first) on the ground and cured. They were then lifted and set in place, using nothing more than a team of four (these rafters were limited to maximum spans of 4 metres). Props are placed at 1.5 metre intervals of each rafter to ensure that no buckling or cracking occurs during construction. The pre-cast filler blocks were made using a custom template on an egg-laying type block making machine. Once cured, they would be lifted into place and set on the protruding flanges of the t-beam. Above this, a grid using welded mesh is placed to cater for any upward thrust. Apart from that in the rafters, this is the only steel in this kind of slab. Concrete is then poured over this to create a layer of 1.5-2 inches above the pre-cast blocks.
As a total, this building used about 1.4 kg per sq ft of steel.... A saving of about 40% steel when compared to a conventionally built structure. (this is in spite of the extra steel used in the RCC tie bands as seismic area construction, and in the precast slabs used to cover the cooling tubes).
Finalising a resource sensitive block
Bellary has predominantly black cotton soil, so the architects had originally opted for a site-cast concrete block for the masonry. I remember having pursued a more resource efficient block from the get go.... We collected soil samples and tested them in Bangalore (including at the IISc Civil Engineering Department). We got mixed results. Then a eureka moment... the Kudithin cement plant had been procuring hundreds of tons of GGBS (ground slag) from the nearby Jindal steel plant. GGBS is a by product of the steel manufacturing process. This was used in the cement that the plant manufactured... and was a pozzolonic material. We checked this out as a substitute at the IISc lab and found that we got incredible strengths even at a high 40% GGBS constitution of the block (the remaining being quarry dust and cement).
The block manufacturing was initiated at site using manual presses, which resulted in the manufacture of over 800-1000 blocks per day. These blocks were designed as 200 thk blocks and were to meet a density requirement of about 2.0 kg/cm3 to ensure a requisite thermal mass design to meet the thermal dynamics of this design. While the contractor employed for the construction of the prototype building was very experienced in soil block making and other alternative construction technologies, we encouraged and roped in three other vendors in block making using the GGBS mix. They would come in handy for the block making for the main project. Despite the expensive procurement rate for the GGBS, we were able to make these blocks more economical than the originally envisaged site made concrete blocks.
An interesting anecdote is that ACC, which had originally initiated building several kilometres of boundary wall around and within their campus with concrete blocks, shifted to using these GGBS blocks.... as it also made financial sense. A big impact of the interventions of the entire team of architects and engineers.
Another impact of building use these site made GGBS blocks, were that we could control quality and due to the good consistency of these blocks, we could afford to leave the walls exposed. Of course this meant that we had to opt for some surface pointing to secure them from any untoward seepage. Being grey, this did mean that an interesting enough aesthetic had to be developed to avoid getting a dull appearance..
Reclaimed timber
At IGH we had been keen to push earlier thresholds of using alternatives for regular timber for doors and windows. The small scale merchants of old timber doors and windows in various parts of Bangalore had always intrigued us and showed promise if only we could use this wonderful resource at a larger scale. These merchants are small time operators and mainly cater to smaller requirements.
The properties of such a timber source is that it can be used as is, if the door/window component is in good shape, or has to be re-sized, planed and finished to suit the new design. The wooden members bear the scars of nails and pegs, that would have been removed in the resizing exercise. Care has to be taken to develop an aesthetic that incorporates these blemishes and scars (which add character to the wood), or, to mask them appropriately. A big benefit of the exercise is that wood can be considered as super treated wood due to both the more thorough treatment processes followed back in the day, and due to the natural conditioning of this wood over the years. Chances of deflection are extremely rare in the use of such wood. Another important aspect to consider while using such wood is that since these merchants don't segregate the wood based on wood type (neem, mathi, teak, sal, etc) the raw material is a mixture. The most one can do (with ease) is to ensure that each door component, is made from one wood. One can tone, or, paint over to bring an element of congruity over a much larger usage.
Most of this wood is sourced from areas that are seeing great urban renewal.... mostly smaller towns of Karnataka. The primary source is a demolition contractor who then re-sells these wooden components to these reused timber merchants.
ABLA was thrilled to have this value addition. The challenge was to find sections that were as wide as the designed double shuttered windows.... we just about managed to get a guarantee of the sections of that width for the entire project. We prepared a list of reused timber merchants and ensured that we could manage scale by using a group of vendors, instead of depending on just one. Eventually, the architects chose to paint these windows and doors with a colour scheme inspired by how rural homes around Bellary always articulated their doors/windows in resplendent colours. 
A lower energy floor
Bellary is situated at the border of central Karnataka and Anantpur in Andhra Pradesh. It is a dry arid belt, and is close to some repositories of granite (in Karnataka) and some slates (from AP). Originally, a granite was considered for all the flooring, but after discussions it was felt that we could achieve a further lower embodied energy footprint by opting for a pigmented cement floor. The logic was that since cement mortar forms the base of all stone floors, we could achieve this by simply eliminating the stone above, and rendering the cement floor well.
The challenge, however, was to get good skills to make these floors. We chose to go for an ochre coloured oxide floor, which would create a nice contrast to the grey surfaces of the GGBS blocks.
We went through a number of mixes of cement and different yellow oxides, and finally settled on the use of white cement instead of grey, and a minimum thickness of 3 mm of this mixture. This brought out the colour of the floor, and avoided the revealing of the lower grey cement base due to the additional thickness of this coat.
It had been common practise to use glass or brass strips in these concrete floors (also seen in cast in-situ mosaic floors) to control expansion cracks. This was not appealing to the design team, so an interesting, but more labour intensive method of laying this pigmented floor was chosen. The floor areas were divided into a 1m x 1m grid of panels. Alternate panels were cast first, and once set, the remaining panels were cast. Yes, this did take a bit more time than casting this floor in one shot, but it also meant that chances of large size cracks would be limited as one could consider the casts as limited to a smaller size, and therefore leading to a controlled expansion and contraction... leading to lesser cracking. Apart from a vibrant aesthetic and being a more resource efficient alternative, this also saved the client money as a pigmented cement floor costs much less than a stone floor.
Oh... those high energy industrialised tiles (vitrified, ceramic, etc) were not even an option!!
Bamboo engineered wood replacing plywood
As per the thermal management design of this building type, adjustable screens were provided in the verandahs. The purpose of these screens was to provide an adjustable thermal barrier when needed. These screens were panels that were built around a metal frame. The core layer was insulation and it was clad with plywood and a thin veneer on either side. To reduce the usage of conventional wood (plywood being a contributing factor) we proposed the usage of Bamboo mat board, BMB, as a replacement to the plywood. BMB is an engineered product that is a glued laminate of several bamboo mats. As BMB was attractive by itself, one did not require the use of a veneer over this. BMB is akin to marine grade ply and some manufacturers make versions that are external grade, with a protective UV resistant coat. Bamboo being a renewable resource (it is actually a fast growing grass and not a wood), is the ideal resource for the manufacture of woody boards, sheets, etc. An aside- bamboo is said to sequester more carbon than most woods.
There are a number of manufacturers of such Bamboo Enginnered products in the country, but there are differences in quality. (incidentally, there are is a Bamboo Mat Corrugated Sheet, BMCS, alternative to corrugated tin sheets.
A non-toxic anti-termite method
Sustainability or not, whether we withdraw water from the ground of not, the usage of any toxic substance for any activity is a strict NO. Anti-termite solutions are injected in great amounts into and around the excavation works during the start of construction, and we were concerned about such mindless injection of toxins into the soil. An alternative neem-based solution that we had been using for many years was employed to overcome this. The application method is pretty much the same,.. the difference being that the vendor who promoted this product would readily take a swig of this solution to drive home the point that it was harmless to humans, and not a poison.

Apart from these main interventions, there were many other significant but often overlooked options that were put in use in the construction of this building. For example-
  • the usage of quarry dust instead of sand in plastering, mortar and concrete..... which is mostly dredged (illegally) from riverine systems
  • the architects designed an attractive masonry railing, which used thinner GGBS blocks between bands of kadappa (a slate) and bethamchella (a smooth limestone).... reducing the usage of steel.
  • the architects, along with the structural consultant, designed an interesting box trench foundation, specially for the black cotton soil of this region. Essentially, it was a lean concrete mix using large stone aggregate that was filled into this trench and allowed to cure. It was simple to execute and saved us many man-days, and did not need any reinforcement.
In parallel, while the mock-up building came up, other works related to the rest of the main project had been initiated. While the usual large scale vendor finalisation and tendering processes unfurled, another interesting story involving bamboo is worth covering.
As part of the campus, the architects had developed an interesting club building. The form was dramatic, with a gently angled roof protruding from two sides and held over slender built-up columns. The span of the building roof was 120ft x 80 ft. This roof was originally designed as a series of steel trusses (curiously designed to have an inverted arc like profile as it's bottom section) supporting a galvalum sheet roofing. There was also an interesting heat management process designed by the incorporation of a 'silver ceil' insulating fabric stretched across below this truss, ensuring that whatever heat is gained by the roof, is not transferred to the large hall below. The architects had designed this interesting mechanism to manage the venting of this roof.
While we could not but be appreciative of this design, we felt that we could try an alternative to those steel trusses. We proposed the use of bamboo trusses, and even roped in a specialised agency, WonderGrass, to back this. It was decided that a prototype of this truss would be developed in full scale and tested. Apart from this the prototype for the roof structures of three utility buildings (housing the barn, cowshed and gassifier) was also proposed. We worked with ABLA and WonderGrass to finalise this truss design and the prototype development was initiated. As a result we have managed to assemble and erect an 80 ft long truss... a testimony to the structural properties of bamboo and an elegant alternative to steel.

The ACC Greens Village is significant as it highlights innovate use of cement, apart from other building materials & systems, in creating a low ecological footprint built environment. It was also a momentous occasion for ACC, having achieved a significant milestone towards its agenda in promoting sustainability. Here's to the rest of the project.
Click here for more pics of the project.