Is HempWool the Holy Grail of Sustainable Insulation?

From Belinda Carr.

HempWool is a plant-based, sustainable and high-performance insulation for walls, floors and ceilings. It provides resistance to the flow of heat and lowers your heating and cooling costs. It is quickly gaining traction in the construction industry, as a replacement for traditional insulation.

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0:00 Introduction
1:08 How its made
4:16 Holy grail Airlay
5:56 Progress
6:44 Types of HempWool
7:17 Sustainability
8:32 Fire Resistance
9:49 Conclusion

HempWool is a natural thermal insulation made from the fibers of the hemp plant. Bales of shredded hemp arrive at the manufacturing facility from all over Northern States and Canada. The color of the dried hemp fibers varies depending the amount that it is retted. Retting is a process that allows moisture to begin separation of the fiber from the stalk. Darker fiber has been retted for longer, and lighter fiber has been retted for less time. HempWool can also include sheep wool from New Zealand or recycled wool. Hempitecture’s acoustic insulation batts use recycled and virgin cotton for better sound absorption. To bind and fuse the hemp fibers together, they use a small amount of polyester bonding fibers.

After the polyester fibers melt and fuse the hemp fibers together, the hemp wool batts are cooled down with exhaust fans and moved to the cutting station. Large circular blades that look like pizza cutters cut the insulation batts down to 16” or 24” widths. A guillotine blade cuts the batts to the final length, usually 48”.

Right now, they are scaling up production of 4 insulation batts. The thinnest ones are 2” and 3.5” that fits into a standard 2×4 stud bay. They also have a larger 5.5” thick batt that fits into a 2×6 stud bay. The third product is a massive 7.5” thick batt that fits into 2×8 studs bays. All these batts have an R value of 3.7 per inch. (*they are working to prove this result under American testing parameters). So, this particular product would be great for an exterior R30 wall.

Hempitecture is experimenting with other types of HempWool products like thin underlayment for carpets. This flexible material could be used instead of rubber, wool, foam or any other synthetic fibers. They have also made an exterior rigid board panel that can be used as continuous exterior insulation. This product is much stiffer, more waterproof and it’s fire rated.

When exposed to a flame, the surface of the material darkened, but it did not catch on fire. It didn’t even smolder. This is a huge accomplishment from the previous iterations of the product. I was also impressed with its water resistance. Water puddled on the surface for a while, before slowly sinking into the top layer of the fibers. As you can see, the water did not seep through the entire insulation batt. It was only absorbed by the top layer so the batt maintained its shape and structure.

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#ecofriendly #insulation #construction #building #automation #hemp #buildings