Among the various materials that are used in green building, one of the most popular is the lime, which has the advantage of being a natural and environmentally friendly solution. Longevity is its best gift, but certainly not the only one: lime, in fact, is recyclable, and lends itself to a great variety of applications for the enhancement of numerous restoration and recovery projects. Its breathability is very high, and its natural constitution is a quality that deserves not to be underestimated. In addition, it is necessary to take into account its more than moderate resistance to thermal excursions: this is the reason why the articles made of lime are able to last a long time.
All the advantages of lime
But the benefits offered by this material do not end here: its hygroscopic characteristics, in fact, ensure that it has the capacità di absorb moisture and release it. This translates into an increase in the living comfort of the various environments, while preventing the appearance of molds and condensation phenomena are limited. What is certain is that lime is also an optimal choice from an ecological point of view: once it has been applied inside the walls, it absorbs the carbon dioxide that it had expelled during cooking and returns to limestone.
The history of lime
Lime has been used since ancient times for plaster and construction mortars, just as we use it today for green building and restoration. In the past, moreover, it was used for the construction of floors and to paint the walls. Furthermore, the profession of lime kilnsman enjoyed a great reputation in Roman times. It has been verified that lime-based binders are the only ones that are completely compatible with the typical materials of ancient buildings, due to their considerable mechanical resistance and the important porosity values, as well as in terms of thermal expansion.
Lime today and yesterday
Various references to the Magister Calcariarum have been found on various votive stems that have emerged during archaeological excavations, demonstrating the importance attributed to the lime kilnsman. Even a famous person like Marco Pollio Vitruvius took care of describing in detail the techniques used to make the mortars: a mixture of sand, cocciopesto, pozzolana and quicklime known as opus caementicium was used. Long-lasting and resistant, pozzolanic mortars have defeated the effects of time and are still intact now.
Which products to choose
Dehumidifying plaster and earthenware mortar are two examples of products that prove to be suitable for those processes to be carried out in humid contexts. Even if lime is a material used for millennia, technological evolution does not stop, and production techniques are constantly innovated both in order to raise quality standards more and more and with the aim of enhancing natural resources. Precisely for this reason, products conceived and developed specifically for green building are born: they are bio-compounds that provide high breathability values without having to give up the solidity and resistance of lime.
Pozzolanic lime is a type of hydraulic lime that derives from the cold mixing of pure aerial lime with other materials, while calcesana is a type of natural hydraulic lime to obtain which marly limestones are cooked in traditional ovens. Pure lime putty is another solution that can be referred to in the construction sector, and is made with completely extinguished fatty lime with a high content of calcium hydrate.