Wood fiber insulation has been a $700 million market in Europe, and it is now making its way into the US building industry. In this article, we will explore how Gutex wood fiber insulation is made, the different types available, and its pros and cons.
How its made
Gutex wood fiber insulation board is manufactured using ground-up post-industrial waste, along with recycled wood chips and shavings. Before the wood is shredded into small pieces, a large magnet is used to remove any magnetic impurities. The wood fiber can then undergo two processing methods: wet or dry.
In the wet-process, wood chips are boiled with water and chemicals to break them down into fibers. Sugars, which can attract fungus and mold, are removed, and the slurry is poured onto a sieve and compressed to remove excess water. Steam is used to soften the natural lignin and bond the fibers together. This method produces boards that are ¾” or 20mm thick, but they can be laminated with glue to create thicker boards, up to 4” or 120mm in thickness. This method is an older but more energy-intensive process.
In the dry process, ground-up wood fibers are mixed with a synthetic polyurethane glue or resin binder called PMDI (polymeric methylene diphenyl diisocyanate). This stable and inert glue does not off-gas, and a small amount of paraffin wax is added to make the boards water repellent. The mixture is laid on a conveyor belt and compressed to achieve the desired thickness and density, after which steam is applied to cure the boards. These boards are made to the desired thickness and are not typically laminated.
Products
Gutex offers various products for different applications. Gutex Multitherm is suitable for both exterior and interior use on roofs and walls. It has tongue and groove joints on all four sides for quick installation. The composition is 95% wood, 4% polyurethane binder, and 1% paraffin, with an R-value of 3.6 per inch and thermal conductivity of 0.04 W/mK.
Gutex Ultratherm is designed for exterior use on roofs, featuring self-shedding tongue and groove edges on all four sides. It contains 95.25% wood, 4% polyurethane binder, and 0.75% paraffin, with an R-value of 3.4 per inch and thermal conductivity of 0.042 W/mK.
Gutex Thermowall is versatile for both exterior and interior applications on roofs, walls, and floors. It can even have a 3 coat stucco applied directly. The product has a butt joint, and its composition includes 94.5% wood, 4% polyurethane binder, and 1.5% paraffin. It offers an R-value of 3.6 per inch and thermal conductivity of 0.039 W/mK.
Gutex Thermoflex, a flexible interior product, is perfect for use between rafters and studs as it easily friction fits into place. Its composition is 86% wood, 6% polyolefin, and 8% ammonium polyphosphate, offering an R-value of 4.0 per inch and thermal conductivity of 0.036 W/mK.
Gutex Thermofiber is a blown-in loose-fill product suitable for use between rafters and studs. It is composed of 91% wood and 9% ammonium salts, with an R-value of 3.8 per inch and thermal conductivity of 0.038 W/mK.
Advantages
Wood fiber insulation has several advantages. It is considered a safe, natural, and high-performing alternative to synthetic options. Moreover, wood is a renewable resource and a natural carbon sink, making these products carbon negative in Europe. Gutex uses wood chips and shavings from nearby sawmills to reduce transportation energy consumption, and the wood is harvested using sustainable forestry practices.
The low thermal conductivity of wood fiber insulation means that it doesn’t easily allow heat to pass through. Additionally, it has a high thermal storage capacity, about ten times that of mineral wool, due to its high density, enabling it to store heat during the day and release it slowly at night.
The products have good dimensional stability, low thermal drift, and no VOCs. They also possess excellent fire resistance, and when installed correctly, Gutex boards can significantly reduce sound levels, making them more effective sound barriers than foam, mineral wool, or fiberglass.
Disadvantages
However, there are a few disadvantages to consider. Currently, wood fiber insulation is more expensive compared to other options in the market. The product is designed for the metric system, which makes it incompatible with the 4-foot grid commonly used in the US. Although tongue and groove joints allow for flexible seam placement, the limited availability of wood fiber insulation may lead to significant lead times once orders are placed.
Conclusion
In conclusion, Gutex wood fiber insulation holds immense promise as a high-performing and sustainable building material. As the US building industry evolves and embraces engineered wood products, Gutex’s offerings are likely to play a crucial role in shaping the future of insulation.
SOURCES
