RPV Green Boards | Sandwich Insulated Panels | Laminated Boards
Magnesium Oxide board “MgO board” is a factory-made, non-insulating sheathing board
product. It can be used for a number of applications including wall and ceiling linings, fascias,
soffits, tile backing and underlayment. It is made of magnesium oxide, a type of mineral cement,
and is commonly called simply “MgO” (pronounced emm-gee-oh) due to its chemical
composition of magnesium (chemical symbol Mg) and oxygen (chemical symbol O). Think of
MgO as a type of sheathing board (sort of like drywall or cement board) but with muchimproved characteristics such as fire resistance, weather ability, strength, resistance to mold,mildew, and so on.
MgO is available in many forms, and for building construction comes in various thicknesses and
sheet sizes. It also comes in various grades, such as smooth finishes, rough textures, and utility
grades. It is white, beige or light gray in color, and has a “hard” sound when rapped with your
knuckles–somewhat like Portland cement board. There are dozens of companies that make MgO
board, most of which are in Asia. There are several large producers, but most are small local
manufacturers who serve a region.
Not much MgO is used in North America so far, but no doubt will become much more widely
used in the future.
Pure magnesium is a silvery metal element (it is shown in the chemistry Periodic Table) and is a
solid at room temperature (unlike mercury, also a metal, which is liquid at room temperature).
Magnesium is somewhat like aluminum, but lighter. The so-called “mag wheels” on sports cars
in the ‘60s and ‘70s were actually mostly made of aluminum, but also had some magnesium in
them. Like aluminum, magnesium is usually used in alloy form, particularly for lightweight high
performance structures like airplanes and racecars.
Pure magnesium, in raw form, is not stable–it burns–they make flares and fireworks from it.
MgO, however, is the exact opposite. It is completely non-flammable and used for fireproofing
and as furnace liners.
Oxygen, when combined with magnesium under heat and pressure can produce a stone-like
material: MgO. MgO exists in gigantic deposits as raw “rock” and is mined like other minerals.
It is ground up into a powder, which is then combined with water to make a cement-like
(adhesive) material. About 70 percent of the world’s MgO is in Asia. Other deposits are located
elsewhere around the globe, but not all have the correct quality for making sheathing. There is
sufficient mine-able MgO spread around the world to make enough “MgO drywall” for
centuries. MgO board also contains other magnesium-based components, but MgO is the main
In addition to the base material of MgO, other types of magnesium ‘cements’, wood flour, and
various additives are included to improve manufacturing and enhance various properties. Most
MgO boards have some type of fibrous reinforcement within the core and/or on the face. Often
this takes the form of glass mesh, fibers, or a fine screed. MgO boards also contain other
additives to enhance flexibility and weather-ability. In other words, there are various types of
MgO boards, but most are essentially the same in terms of their basic composition.
MgO boards are made as individual pieces that are cut to length as they are poured onto a casting
tray. The initial set occurs horizontally, but the final cure occurs vertically or with spacers
between the sheets. The MgO is cast in a liquid slurry-like form (a mixture of MgO powder, and
other additives and water) and sets up by chemical reaction - much like Portland cement does in
stucco or concrete. The cast boards are then cured at ambient temperature. MgO boards do not
contain asbestos, but some have different types of micro fiber reinforcing. This reinforcing is
separate from the surface scrim, and is part of the MgO slurry used to cast the MgO sheets.
MgO is made in a number of areas around the world, and especially near areas where MgO
deposits are mined. Major deposits of MgO do not occur in the USA and Canada; China and the
Mideast have large deposits.
The use of MgO goes back many centuries, almost to the Pyramids. It
was originally used to make mortars for masonry construction.
Nowadays, in many countries, MgO is often used for mortars. In North
America, Portland cement is used most of the time.
The modern use of MgO to make sheathing panels goes back several
decades. MgO boards have been used in Asia and the Middle East on
many large, world-class projects, particularly for partitions and fire walls. This new-to-us type of
sheathing has a long, successful track record.
MgO boards come in various forms. The thinnest boards are about 1/4-inch thick, while the
thickest are about an inch. Sheet sizes are similar to those of drywall.
Various surface finishes are available for MgO board. Some are super smooth and paintable asis, while others are rougher and better suited for non-aesthetic purposes, such as structural sheathing or a tile backer board, or for the application of thick coatings.
MgO board is a “low tech” and “energy-friendly” product. CO2 is high on the list of
“greenhouse” gases, which are said to contribute to the global warming phenomenon. MgO
production is simple, energy efficient, and produces few “greenhouse” gases. This aspect of
MgO, from the standpoint of being a ‘green’/eco-friendly product, would indicate that MgObased products would have a bright future.
In many applications, MgO boards can be used in the same ways as gypsum and Portland cement
sheathings. The substitution is not fully direct in terms of sheet thicknesses, fastening methods
and joint treatments, but is very similar. This makes MgO board an easy product to use. The
possible uses of MgO board are vast, and some of them include:
• Structural sheathing for wood or metal stud walls.
• Shower stall tile backer board.
• Facings for structural panels engineered to use MgO as the facing.
• Shaft liners.
• Substrates for coatings and insulated systems (such as Direct-Applied Finish Systems, EIFS,
The properties of our proprietary patented formulation and compounds, along with the proper curing process attributes to the strength and performances of RPV Green Boards that well exceed that of the traditional FC, Drywall, OSB and Flat Sheet products.
The following is a list of the independent testing carried out on:
RPV Industries has a wealth of knowledge in manufacturing Structured Insulated Pannels using Rockwool, XPS (extruded polystyrene) and polyurethanes foams. We can organize customized Wintech cutting for different EPS panel designs to incorporate structural feature, electrical and plumbing services. There are many SIPS systems and most require a joining system or method, we can help advise and custom design the panel to incorporate a joining system. We have also done extensive testing on adhesive systems to suit almost any application in the panel manufacturing process.