Talk about sustainable modes of construction, and the first concept that emerges is mud, clay bricks, fly ash, plantation or salvaged wood, to mention a few. The entire concept revolves around using materials with the least carbon footprint, especially locally sourced. The construction methodologies are expected to be location-centric and site-sensitive, even the design tweaked to meet local conditions and modes of construction and material use.
In this context, steel as a material features on the other side of the spectrum, given its acknowledged carbon footprint. Incidentally, the most sustainable construction methodologies tout the absence of steel to reiterate their strong green quotient. Yet, a walk through the works of Architects Piyush Kapadia and Pooja Kapadia of Pooja & Piyush Associates speaks a totally different story; the duo’s projects come with a strong green quotient where the construction is done not with mud or clay but steel.
Veering towards a complete steel construction, their buildings are assembled in record time, akin to a set of Lego blocks where the entire structure is erected using steel pipes connected in place using nuts and bolts. The steel story of Pooja and Piyush began when they received the project Heer Radha Residence to execute. Just before this project, the duo had to complete an industrial project where the execution time was extremely short, prompting them to adopt pre-engineered techniques to complete the project in a record two and half months.
The execution of this project made both realise that similar techniques and approaches can also be extended to residences too while keeping the green quotient high. Thus started their tryst with steel, yet keeping intact the sustainable aspect.
“The embodied energy going into steel is accounted for when it is manufactured. But if it can be dismantled and reused, the reuse of it negates this, bringing in the sustainability factor. The fact that the construction is fast, durable, can be easily altered and is less labour intensive also makes it a fine choice for residential and commercial buildings”, explains Piyush on the choice of steel as a green material. He further opines that it is all about the mindset of the unconventional nature of the structure.
Composite steel structure
Adopting this perspective, Piyush and Pooja came up with a composite steel structure for the Heer Radha Residence, where the structure comes with no lintels, no overhangs, and no sunshades. PVC replaces the use of plywood, and salvaged wood is used where wood is required. There is also an absence of plastering as well as POP, resulting in the reduction of cement used to the tune of 55 per cent as compared to a conventional structure.
Since there is no concrete but only steel being used, the foundation required is also light, with the columns and beams featuring in the building being steel sans the concrete. The walls are built using clay blocks where they remain exposed without plastering, once again saving the use of cement and sand, all of which pare down the carbon footprint.
The ceiling is RCC but is again exposed without plaster, saving on the use of cement and sand. “An interesting aspect of this structure was the accommodation of all factors that were earlier shunned or negated by our earlier clients. This makes the project literally an exhibit of all that was considered inappropriate as appropriate,” smiles Piyush.
Easy adaptability
To lend a sense of timelessness, the structure is kept totally white, the design language lending itself for easy alteration to adapt to changing requirements and lifestyles over the years. The climate responsiveness of the building is high, designed specifically with balconies to buffer the heat ingress.
“The design resonates with the vernacular approach to buildings where large verandas marked the residences on all four sides as buffer zones.” Further, the orientation has been deftly addressed to let in the cool breeze during the day. The ground level is designed with open free sections so as to evolve over time “where alterations to changing requirements can be done with ease and least disturbance to the structure.”
The interior free-flowing spaces also come with an absence of walls to demarcate functional zones, once again reducing the structural form and the ensuing carbon footprint. “We have cleverly used wardrobe cabinets as demarcating elements between functional zones rather than structural walls. This again makes the spaces totally flexible and easily adaptable to changes by merely removing the storage elements”, points Piyush.
Keying in natural insulation
If the green quotient is to rule high, natural insulation of the interiors is imperative. The structure comes with a dynamic elevation where the aluminium pivoted louvres wrap the façade, featuring rotatable fins. Northwest and Southeast are known for bringing in maximum heat ingress into the interiors. Piyush and Pooja stemmed this by structuring the walls on this section in perforated clay blocks to offer insulation.
The terrace comes layered with glazed tiles to reduce heat ingress further. The walls featuring on the service section housing the toilets, are built using lightweight Aerated Autoclaved blocks to permit utility conduits to run through them. “These walls also reduce the load on the structure besides reducing the use of brick and mortar”, elaborates Piyush. The residence further uses solar power to address 90 per cent of its power requirements, adding to the green quotient. The passive cooling methods opted for, and the ample natural light seeping into the interiors once again reduces the consumption of electricity by 25 per cent.
Potential as future mode of construction
“Given the reduction of walls in the residence by three times, the area needing to be painted also comes down drastically, again adding to the green footprint in terms of maintenance and usage of materials during the lifetime of the building”, states Piyush. Since there is a reduction in the walls, the weight of the building is reduced to half of a conventional building of the same size.
“Though the cost of steel used is about 10 to 15 per cent more than a conventional building, the easy recyclability of steel as a material along with the greater possibilities of keying in other green factors makes this construction methodology a potential future mode of construction”, opines Piyush.
Nuts and Bolts Residence. | Photo Credit: Pooja & Piyush Associates
Replicating it further
Taking forward the learnings from the Heer Radha Residence, the duo built their succeeding project, the Nuts and Bolts Residence, too, in steel. Coming up on a narrow 10x15m site with two side roads, the ground plus two structure is built using circular steel columns that feature on the periphery, leaving the interiors open and flexible. The eastern sections come with larger openings, while the west side is shielded with utilities, successfully addressing the orientation of the building. Perforated clay blocks on the outer walls add to the interior insulation.
Salvaged vertical wooden rotatable louvres cover the façade, replacing conventional grills. Ample cross ventilation and the facility to suck out hot air through vents successfully address passive cooling. Greens wrap the louvres in the elevation to add to the cooling. The building is marked by an absence of sunshades, lintels and balconies, speaking a language of terracotta, exposed steel, wooden louvres and greenery. The structure was erected in just eight days, while the entire project was completed in four months.
Picture credits: Pooja & Piyush Associates
