Magnesium based cements are some of the oldest building materials in the world, first used around the same time as gypsum. Unlike gypsum plasters though, magnesium phosphate cement is very strong, impervious to the weather and was used as mortar by the Romans, in the Great Wall of China, to build Stupas in India, to protect wood structures like the Forbidden City, and in 800 year old timber buildings in Europe.
About sixty years after Joseph Aspdin invented Portland cement in 1824, Stanislaus Sorel rediscovered magnesium based cements and they have continued to be used for specialty applications like high temperature kiln linings, patching cement for airport runways and bridges, oil well mud, and hospital and institutional floors to name a few.
Around fourty years ago, Vance Steyner reverse-engineered mortar from the Great Wall and from this MgO board was developed in China where it has become a popular construction material for walls and ceilings. For the Beijing Olympics, MgO boards were used extensively as the premier material to make the games more environmentally sustainable. Taipei 101, the world’s tallest Platinum LEED building, uses it extensively on walls and ceilings, inside and out for decoration and fire proofing. In some places in Europe it is replacing OSB as the sheathing of choice due to its strength, durability, and ease of use.