Dhamani structure, housing 22 family members in Maharashtra’s Sangli district, grabbed regional media’s attention in 2009. There was a sea of visitors outside the newly constructed yellow home, made from local bricks and recycled materials.
Everyone wanted to know how the 2,200 sq ft house, accommodating mango and coconut trees, was constructed with a budget of merely Rs 8 lakhs.
The monumental feature of the house, its arch which celebrates the old architecture, is at the heart of the structure. The skylight slits on the ceiling help hot air exit and allow cool air to enter from the lower rat trap cavity in the walls. Rat trap cavity method is a brick masonry method of wall construction. Here the bricks are placed in vertical positions instead of the conventional horizontal positions, thus creating a hollow space within the wall.
“We slashed construction costs with our vernacular material palettes like stone and bricks and use of climate-responsive designs such as brick vaults and arches,” Praveen Mali, co-founder of ABHA Architect tells.
The aesthetic and architectural principles of Dhamani house can be reflected in the 19-year-old firm’s construction projects. Mali started the sustainable firm along with his wife, Vidya, with the sole purpose to build green homes by using traditional practices. Integrating aesthetic designs like a dome, arches and vaults is their unique selling point.
The Sangli-based husband-wife duo draw inspiration from William Laurie Baker, the British-born Indian architect and pioneer in constructing sustainable homes using mud and other local resources.
“As the construction industry flourished with an influx of modern construction materials like cement, glass and marble, we started devaluing traditional methods. People’s definition of a house changed, as it turned into an asset with a long-term investment. Investing money in a house that didn’t match modern conventional standards was not appealing any more. We wanted to remind people that ancient constructions have lasted for centuries in India. Buildings were built in a way that respects the climate and we need to reinforce that,” says Mali.
From residential, commercial to institutional structures, the duo has constructed nearly 300 houses across Maharashtra and Karnataka. In the majority of the houses, the duo has been able to save 25 to 30% of costs with their innovative designs.
Mali and Vidya share why they are bringing back the norm of domes and arches along with insights into their eco-conscious material palette and passive cooling strategies. These are not only cost-effective but are known for their durability and disaster-resistant features.
Repopularising Domes to Arches
Besides, the historical significance and symbolism, the semi-circular arch, the vault — an arched covering of stone, and the dome hemispherical structures have several architectural advantages.
“Due to its ratio of high volume to the surface area, domes require less building materials and thus use less energy. It promotes thermal insulation and maximises solar gain. Since domes are corner-less, they allow for optimum air circulation. As for the arches, a two-dimensional curved beam construction, they can carry a much greater load than a horizontal beam can support. A vault [French voûte, from Italian volta] is a type of arch, usually of stone or brick, serving to cover a space with a ceiling or roof,” says Mali.
Based on their low-cost and aesthetic appeal, Vidya and Mali have successfully convinced many clients to adopt biblical designs.
Recycled Materials, Fly Ash Bricks & More
Entering with ideas of eco-architecture in an arena littered with carbon-emitting construction materials was not easy. Not only did they have to deal with a lack of sustainable construction materials but also grapple with people’s ignorance.
“More often than not, we have to hunt for appropriate and quality building materials that may delay the construction process. We even started manufacturing our own bricks in the process but had to stop due to some reasons,” says Vidya, adding, “We patiently explain the benefits of all the materials used and their historical significance.”
Brick is the most striking material in every structure by the Malis. Different types of bricks like burnt bricks, recycled, fly ash and compressed mud-brick form the foundation of the building.
“While burnt bricks are durable and resistant to abrasion and fire, fly ash bricks are lightweight and absorb less heat. The wire cut bricks can be made from discarded bricks and mud bricks are low cost and low embodied energy,” explains Mali.
The use of bricks and other materials like stone, tiles, wood, walls and fillers depends on the geographical location. For example, in Konkan regions, they use laterite stones and wire-cut bricks dominate in the Southern region of Maharashtra and Karnataka.
Cost-Effective & Climate-Responsive Strategies
Vidya and Mali have always eschewed modern architectural techniques like Reinforced Cement Concrete (RCC), steel bars, steel plates due to their carbon emission-causing factors. And facts back their claims. For instance, cement generates around 8 per cent of global carbon dioxide (CO2) emissions.
Malis opt for load-bearing structures over RCC constructions. In this system, walls bear the load of the roof. It is more economical and ecological than RCC.
Ventilation, controlled open spaces and distinguishing passive cooling methods are reflected in each of their near-perfect projects. This is achieved through verandahs, courtyards, rat trap cavity walls, roof tiles and filler slabs.
Explaining the technicalities of such methods, Vidya says, “Filler slab is an alternate slab construction technology where part of the concrete in the bottom of the slab is replaced by a filler material like Mangalore tiles or clay pots. Both the rat trap method and the filler slabs provide thermal insulation, resulting in cooler interiors during summer and warmer interiors during winter.”
On a parting note, Vidya and Mali reinforce the need to combine sustainable practices and traditionally significant designs for a greener future.
“We must try and treat the Earth as our home and refrain from polluting it. Civil construction plays an integral role and if architects, builders and engineers move towards the eco-friendly process now, we will see a tangible result in future,” adds Vidya.
The story has been extracted from Couple Use Domes, Recycled Materials To Build Homes; Save 30% Costs (thebetterindia.com)