For most of the past 100 years, residential and commercial construction has relied on three main building products—drywall, oriented strand board, and plywood—to form the sheathing and underlayment of our structures. That reality may be on the precipice of a transformation, however, thanks in part to a substance as old as the Great Wall of China.
Magnesia has been used for millennia as a building component. The builders of the Great Wall mixed it with their mortar, as did the Romans to create a concrete-like substance. Known today as magnesium oxide (or MgO), it’s available as panels through a variety of brand names and manufacturers that include (among others) Exacor from Huber Engineered Woods, Magnum Board Products LLC, MagPanel from Ambient Building Products, Inc., and Cem-Rock by NexEra Greenspan USA.
What is it?
But what, exactly, is MgO? It starts as pure magnesium, a metal element that is solid at room temperature. In its raw form, however, magnesium is unstable and highly flammable. MgO, however, is the exact opposite. It is non-combustible and refractory, meaning it’s chemically and physically stable at high temperatures.
Magnesium oxide is a compound made up of two magnesium molecules and two oxygen molecules. When oxygen is combined with the magnesium under heat and pressure, it produces a stone-like material—MgO. The MgO is then ground into powder and mixed with water and other materials, and then pressed into panels that are reinforced with layers of glass fiber mesh. The panels are similar to drywall or cement board, but MgO manufacturers say the product is stronger, fireproof, and more resistant to mold, mildew, moisture, and weather.
MgO boards can be used in many applications across both residential and commercial builds, including as fascia, soffit, tile backing, wall and ceiling surfacing, and underlayment. The panels are available in a variety of sizes, thicknesses, and properties that allow them to compete with traditional gypsum “drywall” boards, oriented strand boards, and plywood.
Product benefits
According to MgO panel manufacturers, the product possesses several benefits over traditional underlayment and sheathing options:
Ease of installation
MgO panel manufacturers claim that the material can be installed 30% faster than traditional wet-laid gypsum in underlayment applications and only require a single trade. According to Huber Engineered Woods, (maker of Exacor MgO panels), because the panels are installed by framers, it can eliminate the need for gypsum underlayment applications, so there is no need to schedule that additional trade to complete installation.
Fast to finish
The panels are reported to be able to achieve Level 5 finishes in half the time, using half the mud and paint.
Fire resistance
MgO panels are a Class A1 fire rated product, and manufacturers report that the panels actually release water vapor during a fire event, helping to cool and contain the fire.
Water resistance
Manufacturers report that MgO panels are impervious to water and moisture and are dimensionally and structurally stable even when stored outside. (Long period exposure to moisture, however, is not recommended.)
Termite proof
The chemical compound that forms MgO panels is reported to act as a deterrent to termites and other wood boring insects.
Green building
According to manufacturers, MgO panels are eco-friendly. They are recyclable and landfill friendly, to the point where the product acts as a nutrient when it is group up and distributed into the soil.
As mentioned earlier, MgO panels are currently available from a variety of manufacturers, and production is poised to ramp up for at least one of them. The manufacturer of Cem-Rock will be breaking ground on two new manufacturing facilities—one in Rapid City, SD, and another in Waycross, GA. According to Jeff J. Lassle, president and CEO of NexEra Materials Group, “Because the two manufacturing facilities will be utilizing locally-sourced natural materials, Cem-Rock will be the first MgO board to be ‘Made in America.’”
