Hemp, a plant with many virtues has been present in our regions since ancient times. Grown legally, it grows very quickly and without any fertilizer. Perfectly adapted to our climate, hemp is produced in large quantities without damaging the soil. This shrub with a very fast growth cycle does not require weed killers or pesticides. 100% natural, and very resistant this charismatic plant has found its place in the small world of eco-friendly materials. After ropes and textiles, hemp is converted back into the habitat where it is positioned as an insulator of choice. This week HandymanDuDimanche invites you to discover this insulation as natural as performance.
Hemp, an effective insulator
If the wools of glass and rock have a very strong insulating power they present some disadvantages for our health and our environment. Composed of irritating microfibers that infiltrate our body through the respiratory tract, these insulators are considered potentially risky, especially during their installation, which requires many precautions. They are also banned from our German neighbors, who consider their carcinogenic manipulation (we will come back to this in a future survey on the problem of mineral insulators). It is therefore better to replace them with healthy and environmentally friendly materials, such as hemp.
Thanks to its high insulating power and the many benefits it brings, hemp is constantly developing in the French ecological habitat market. With a low coefficient of conductivity of 0.039 (between 0.041 and 0.050 for mineral wool), this insulation is ideal both during the cold weather and during the summer. Not content to protect us from thermal variations, hemp is also an excellent sound insulator.
Hemp in all forms
It is mainly the chènevotte, bark of the stem of the hemp which is used to isolate our houses. Too much moisture and little fire resistance, the chènevotte is necessarily treated with other materials during its conditioning to improve its resistance to fire. There are different forms of hemp insulation, which affects the efficiency of the installation. Hemp wool, in roll 10m, 0.60m wide for 80 to 100mm thick, is used for roofs, attics, slatted floors and caulking. Woolen panels, semi-rigid, 40mm thick, with a length of 1m35 and a width of 0.60m are recommended for elements with frame where they are easily installed. The pile, arranged in bulk is used for manual filling or mixes with lime concrete to arm it and make it more insulating. Hemp fiber it also mixes with lime, to which sand is sometimes added to create slabs, ideal for an "old stone" effect. Stabilized and silicate treated fibers also allow for bulk use and manual dumping of hemp. If they offer the best fire resistance, their thermal coefficient is less interesting and their higher price than other types of packaging.
When to use hemp
The rollers and panels are used exactly like mineral wools. They can be placed in the same places, as in attics, floors and partitions. The establishment of hemp is however less time consuming and tedious than that of mineral wool and requires less precautions, hemp being not at all irritating to humans. For its cutting just a rule for this guide and a knife with big teeth. Mixed with lime, the hemp is transformed into resistant and insulating bricks as well from the energetic point of view as from the sound point of view and brings you an interesting hygrothermal regulation. Ideal for interior and exterior insulation, for the doubling of partitions and even for house construction, hemp bricks bring you optimal comfort, in winter as in summer. Resistant to moisture, mildew, flames and insects, hemp insulation is also an excellent repellent against rodents and pests. While hemp is currently one of the best green insulators on the market, you still have to be cautious when you buy it. The ecological side and performance of this material can be quickly challenged by poor packaging. In the market for ecological housing where everything remains to be done, HandymanDuDimanche can only advise you to remain on your guard and to refer to resellers and producers recognized as Natural Materials of France.