The quality of indoor air has a primary role in the health sector: it depends “not only on the quality of the outdoor air, but also on the presence of internal sources of emission and diffusion of contaminants, with a concentration of chemical and biological pollutants that can influence its properties”. The Istituto Superiore di Sanità wrote it in the report "Interim recommendations for the prevention and management of indoor environments in relation to the transmission of SARS-CoV-2 infectious virus”, published during the Coronavirus emergency.
After this emergency, in the near future, healthiness will be the main priority for designers, institutions and families, focusing on the criteria for real estate market evaluation, design and construction.
Green building has already adopted materials that ensure excellent performance in terms of sanitization, including hemp and lime biocomposites. Besides a better thermal and acoustic insulation, the dispersion of a smaller amount of energy, CO2 emissions retained and the least vulnerability to fires, hemp and lime constructions guarantee a perfect comfort and protect the health of the people living there.
The specialist in the reconstruction and building with natural lime and hemp Gilberto Barcella (technical, research & development and commercial director for the division Tecnocanapa by Senini di Montichiari) confirms the features of these materials. “Since ancient times, the lime combined with hemp was used to sanitize and disinfect environments. Specifically, it is calcium hydroxide, which is obtained by mixing the hydrated lime with water in a well-defined proportion. Walls, external insulation, plasters and paints, made both with traditional techniques and projection on the surfaces, are therefore free of bacteria and viruses”.
“At the same time – he continues – the comfort and quality of indoor air are excellent, as these materials control humidity, eliminate condensation and avoid the so-called sick building syndrome”. The World Health Organization coined the acronym SBS (Sick Building Syndrome) to indicate a very precise clinical picture resulting from the stay in buildings (modern or recently renovated) equipped with ventilation and air conditioning systems that do not ensure an adequate air exchange.
Moreover, Gilberto Barcella underlines that hemp and lime buildings require a faster and leaner construction process (thus affecting costs) and as, in the last decade, the European Union has shown a strong political commitment to modernize the construction sector with a lower environmental impact. The first ‘Energy Performance of Builings Directive’ dates back to 2010; in 2018 the regulatory framework was further updated (and made more ambitious) by the Clean Energy Package for all Europeans.
Hemp and lime constructions - which can even become ‘carbon negative’ by absorbing more CO2 than they produce - perfectly comply with the European plan of decarbonisation of the architectural heritage by 2050. As a result, they can benefit from the important economic incentives provided over the coming years. "Considering ecobonus and sismabonus, in Italy, a maximum of 136 thousand euros of tax break for each housing unit can be obtained”, Gilberto Barcella concludes.
