Alternate Construction Technologies for Mass Housing:
Rapid urbanization and economic growth will increase the demand for adequate housing in Indian cities. Mass housing projects can help cater to this need. However, building mass housing using conventional technology is slow, lacks quality, and is detrimental to the environment. In contrast, more mechanized alternate construction technologies substantially reduce construction time, improve quality, produce less waste, and consume less water. Recognizing their potential, the Government of India has launched the Global Housing Technology Challenge program under the Technology Sub-mission of the Pradhan Mantri Awas Yojana – Urban to mainstream the use of alternate construction technologies in mass housing projects.
In this paper, we point out that attempts to increase the adoption of alternate construction technologies may not yield easy results. Based on semi-structured interviews with 40 experts and practitioners from the residential construction industry, government, academia, and civil society and a literature review, we find six major challenges to the adoption of alternate construction technologies for mass housing in India:
(i) high initial investment, (ii) achieving optimal scale required for commercial viability, (iii) reorientation of planning and design, (iv) transportation of building components, (v) lack of skilled professionals, and (vi) consumer skepticism and questions on livability. We conclude with an outlook on the adoption of these technologies and some ideas on improving their uptake.
Urban India suffers from a massive shortage of adequate housing. The number of households living in inadequate housing conditions was estimated to be 4.7 crore in 2018 in urban India (Roy & Meera, 2020). 4,5 The Government of India, under the Pradhan Mantri Awas Yojana – Urban, assessed an aggregate ‘validated’ demand of 1.12 crore houses (Lok Sabha, 2021).
The demand for affordable housing is expected to grow in the decades to come as India urbanizes rapidly, with the urban population to total population ratio of 34.9 percent in 2020 expected to rise to 52.8 percent in 2050, and as incomes grow with economic growth (World Urbanization Prospects:
The 2018 Revision, 2019). Massive reverse migration from Indian cities during the ‘lockdowns’ imposed in the first wave of the COVID-19 pandemic in 2020 reflects that the poor migrant laborers lacked safe and affordable shelter for their families in these cities. To supply adequate housing to the lower- and middle-income segments in Indian cities, mass housing projects i.e., large complexes containing about 500 or more apartments, situated in urban and suburban areas will gain importance (Roy et al. 2007).
The conventional in-situ process of construction uses cement concrete and steel reinforcement to form reinforced cement concrete (RCC) to build a framework of beams (horizontal members) and columns (vertical members). Subsequently, walls are constructed using brick masonry and floors are cast in situ. This conventional process has limitations, particularly for large-scale mass housing projects (Building Materials & Technology Promotion Council, 2021). Assembling the timber-based formwork (i.e., molds into which the concrete is poured) at the construction site is time-consuming, lacks repeatability, and is of poor quality and durability (Kazi & Parkar, 2015).
Building the superstructure (i.e., the portion of the building above the ground level) in the open uncontrolled environment of a construction site exposes the project to weather disruptions and makes it difficult to monitor the quality of construction. This, in several cases, leads to inordinate delays, cost overruns, large quantities of construction waste, and suboptimal quality of the end product (Laubier et al. 2019).
Alternate construction technologies offer an improvement over conventional in-situ construction by mechanising parts of the construction process. These alternate technologies can be classified under four broad categories – alternate formwork systems, prefabricated sandwich panel systems, steel structural systems, and precast concrete construction (Building Materials & Technology Promotion Council, 2021). There are several advantages of a shift to alternate construction methods from the conventional in-situ RCC process.