Frequently asked questions
Most magnesium carbonite comes from China and Europe. The process combines magnesium and oxygen with pressure and heat to create magnesium oxide (MgO). The MgO has the characteristics of stone after heating. After being ground into powder, it gets mixed with water, chloride, and sulfate (or Epsom salts) and wood dust (cellulose), perlite, and a handful of other materials.
The board works in almost every situation in a home. On the exterior, magnesium board products can be applied as wall sheathing, trim, fascia, and siding. Inside homes, magnesium board serves as a tile backer, wall panel, ceiling board, firewall, and drop ceiling tile. Dryboard can also incorporate magnesium boards.
Yes, magnesium oxide boards work the same way as drywall or oriented strand board or any other board product. Builders need no special tools to cut, nail, score, snap, screw, or hang magnesium boards from wood or steel frames. Boards come in thicknesses from 3 to 20 millimeters, with surfaces offered including rough texture, smooth face, versatile, and utility styles. Contractors can finish the boards with paint (just two coats), concrete, and wallpaper.
No, they are moisture-resistant, not waterproof. Extended water exposure leads to hydrothermal expansion. Shorter periods cause no swelling or warping. Magnesium board sellers say exposure of more than an hour may be harmful. Still, magnesium board underneath basement flooring boards protects against moisture. In coastal areas, magnesium board generally withstands salt damage. Outside, the boards should always be covered another layer of materials or coated.
Yes, and magnesium board advocates often cite their fire resistance. It’s highly resistant to flames and carries a UL 055 rating and an A+ from the ATSM. The boards do not spread flames or smoke.
Many environmental benefits come with magnesium board. The curing process captures carbon dioxide. Unlike other competitive materials, the board contains no asbestos, formaldehyde, ammonia, silica, or benzene. The chloride content generally falls below eight percent.
The manufacturing of magnesium board uses 25 to 50 percent of the energy required to prepare calcium hydroxide (slaked lime) or Portland cement. When it comes to downsides, most raw materials used in making magnesium board come from China and have to travel long distances. This negatively affects it’s total embodied energy and increases it’s carbon footprint significantly.
Manufacturers generally use no volatile organic compounds or toxic ingredients in producing the boards. Contractors and homeowners should wear proper silica/concrete dust respirators when cutting and sanding the boards before installation.
The boards are considered nutritional waste that can be recycled, recycled, or ground up and mixed into soil for nourishment. They create no pollution in landfills.
Magnesium oxide board has many attractive qualities. As highlighted earlier, it has excellent fireproof qualities, is energy efficient to produce, reduces waste, and captures carbon dioxide during production. Beyond that, the boards’ fungus resistance means they attract no rot, mildew, allergens, or mold. It’s 20 to 30 percent lighter than other cement-based boards. Contractors and DIYers find it easy to use because of the lightweight.
The first is cost. Magnesium boards cost more than gypsum boards but come close to cement board prices. The quality varies significantly among board manufacturers, with experts suggesting cheaper board provides lower quality performance, not surprisingly. Boards can have unique installation needs, demanding contractors, and do-it-yourselfers follow directions. Some boards may not work as well in humid climates.
Not a great deal. But a group of scientists looked at the issues with magnesium boards, some which emerged in commercial buildings.
Homeowners need to take precautions to avoid small cracking. Cracking can occur if the steel or wood framing behind the panels shrink. Wind and earthquakes will cause cracks. However, those issues remain relatively minor. Most panels installed indoors suffer no damage because the ambient temperature does not change significantly. To avoid cracking, experts suggest allowing for a small gap between boards. A non-shrink caulk should fill space. Paint a primer as a first coat and moisture absorbing paint.
Companies selling the boards cite several reasons why the additional cost, over gypsum boards, make them worth it. Hanging panels using a tile approach makes installation quicker than other boards. They don’t need corner beads, a necessity with gypsum. The panels need no backing materials for cabinets, shelving, and other hanging installations. Since the boards slightly expand, less bracing may be required.
Contractors and DIYers should store boards in a cool, dry area in flat stacks placed on the material instead of the ground. Put nothing on top of the boards to avoid bowing. Place the boards in rooms where they will be installed for two days, prior to installation, to allow them to acclimate.
Any standard finish works on the board, including concrete and synthetic stucco, paint, plaster, stone, tile, brick, fabric, and wallpaper. The panels need a concrete or masonry primer, followed by paints and topcoats. Ask at your paint store for brands and product types that bond well with magnesium oxide boards – several adhere particularly well. Experts suggest testing the paint’s adhesiveness before a full application.
Yes, their adhesive characteristics make for excellent Structural Insulated Panels (SIPS) and Exterior Insulated Finish Systems (EIFS). These systems improve a wall’s fire rating, insulation, and moisture resistance. Many companies are beginning to sell MgO boards as part of structural wall systems, rather than individual panels.