Hemp is a material with innumerable applications because it is very versatile and sustainable: from medicine to nutrition, from the textile industry to the paper mill. It is a sustainable cultivation because it has a rapid and abundant growth; being a weed, to grow does not require irrigation, herbicides and pesticides, nor pesticides and having no protein in it is not attacked by rodents or other insects.
Hemp also has a fertilizing and phytodepurating action. In fact, it is able to reclaim and restore areas polluted by chemical industries.
Hemp cultivation is booming both in Europe and in Italy (about 3,000 hectares, from Federcanapa source): Puglia is the region that produces more, followed by Piedmont, Veneto and Basilicata.
The hemp that best lends itself to use in construction is the cannabis sativa, which is a plant with the following characteristics:
- does not contain THC, so its cultivation is fully legal;
- is grown without the use of pesticides;
- has a very low water consumption;
- it is a resistant plant that adapts to different microclimates;
- it is fast in growth and allows planting even several times a year;
- has a high yield in terms of vegetable mass;
- cleans and re-mineralizes the soil, preparing it for other crops;
- it absorbs CO2 from the atmosphere in such high quantities that it compensates the emissions produced by the other components present in the conglomerate (lime) and brings the emission balance negative (carbon-negative).
The biological analyzes of cannabis sativa show that the canapulo (or hemp wood) obtained from the stem of the dried plant, having a hive molecular structure, is perfectly transpiring, has a high thermal power, is elastic but at the same time durable, thanks to silica content in the fiber.
These intrinsic characteristics of the fiber allow the products in hemp to be:
- excellent thermal and acoustic insulators
- breathable and therefore dehumidifying and anti-mould
- antiseptics and anti-rodents
- elastic and ideal for construction in earthquake zones.
Hemp wood, therefore, represents the inert body of the conglomerate to which it has been combined, as a binder, the hydraulic lime that with its specific organoleptic characteristics, married to those of the canapulo, give life to a material able to perfectly mix and amplify each characterizing element bringing it back into the building product. Lime, therefore, acts as a binder and hardener, making the product antiseptic and non-attackable by rodents and insects, fire retardant and resistant. The mineralization process that occurs by adding water to the hemp and lime composite will make the extremely hard (stone-like) product, at the same time, light and elastic thanks to the incorporated vegetable fiber.
In short, it is an environmentally friendly, biocompatible, recyclable, renewable, compostable material from which we obtain flakes, felts, mattresses, panels, bricks, varnishes, glazes, glues, biocomposites and fabrics for structural reinforcement, which can be used in the building. It has characteristics such as lightness, breathability, resistance to mold and insects, fire resistance, high insulating power (both thermal and acoustic), hygroscopicity (it is a humidity regulator, ie accumulates when it is excess and releases it when the air is too dry).