In today's rapidly evolving construction industry, we've observed a shift towards unsustainable materials, with lime being replaced by cement plaster. However, it's important to recognize the significance of using lime plaster, especially in the restoration of historical buildings, to maintain their original character. Despite the prevailing dominance of cement plaster in the market, our interest lies in comprehending the impact and properties of lime plaster within building spaces, aiming to maximize its potential usage.

Our study is centred on evaluating the hygrothermal performance of lime plaster in naturally ventilated residential spaces. We conducted surveys in 45 traditional buildings in Ahmedabad, India, focusing on measuring ambient variables such as temperature, relative humidity, and wall moisture content. We also investigated mold growth patterns in these spaces and conducted hygrothermal simulations to observe the moisture buffering of lime plaster, comparing our findings with simulation results to enhance the realism of our models. Our simulations utilizing the EMPD model effectively captured the moisture buffering in different materials and predicted indoor conditions conducive to mould formation. This enabled us to identify the risk of mould growth on various wall surfaces and make informed predictions about molud growth in specific spaces. We found that lime plaster is a sustainable and low-embodied energy material with excellent moisture buffering capacity, capable of moderating indoor relative humidity levels and reducing mean radiant temperature. While it is susceptible to mold growth in high humidity conditions, the risk can be mitigated by avoiding non-porous coatings and ensuring adequate ventilation.

Looking ahead, we recommend additional research is conducted to identify the composition of lime plaster and its correlation with mold growth. Additionally, it is essential to characterize its hygric properties for more comprehensive hygrothermal simulations to predict mold formation accurately. A year-round study will enable us to gain a holistic understanding of the interconnected parameters responsible for mold growth.

We hope that our work contributes to the larger literature available towards sustainable choices. We are deeply grateful to ULCOE for providing us with the opportunity and guidance to showcase our work.

Moisture buffering and mould growth characteristics of naturally ventilated lime plastered houses by Vismaya Paralkar (CEPT University, Ahmedabad, India) and Rashmin Damle (CEPT University, Ahmedabad, India) is published in UCL Open: Environment, volume 6, as part of the ICMB23 series.

lime plaster hygrothermal simulations mould growth surface relative humidity conditions