Before You Begin: Planning Your MgO Board Installation
Installing MgO board on interior walls follows a workflow similar to standard drywall installation, but with a few important differences in fastener selection, joint treatment, and cutting technique. Proper planning will save time and help you avoid common pitfalls.
Tools and Materials You'll Need
- MgO boards (appropriate thickness — typically 9mm or 12mm for walls)
- Carbide-tipped scoring knife or circular saw with carbide blade
- Corrosion-resistant screws (self-drilling, 1¼" to 1⅝" depending on thickness)
- Drill/driver
- Tape measure and chalk line
- Fiberglass mesh joint tape
- MgO-compatible joint compound or polymer-modified thin-set mortar
- Safety glasses and dust mask (N95 or better)
Step 1: Prepare the Framing
Ensure your wall framing is plumb, straight, and spaced appropriately — typically 16" or 24" on center. MgO board is denser than drywall, so framing must be solid and well-anchored. Check for any protruding fasteners or high spots in the framing before proceeding.
Step 2: Cut the MgO Boards to Size
MgO board can be cut using a score-and-snap method for thinner panels (up to ~9mm) or a circular saw for thicker sheets. When scoring, use a straightedge and a carbide-tipped knife, making multiple firm passes before snapping. When using a saw, work outdoors or in a well-ventilated space and wear respiratory protection — the dust contains fine mineral particles.
Tip: Mark cut lines on the face of the board and always cut from the face side to minimize chipping on the visible surface.
Step 3: Fasten the Boards to the Framing
Use corrosion-resistant (stainless steel or hot-dipped galvanized) screws specifically rated for use with MgO board. Standard drywall screws can corrode due to the chloride content in some MgO board formulations. Space fasteners approximately every 8" along edges and 12" in the field. Drive screws until the head is slightly dimpled below the surface — do not overdrive and break through the face.
Maintain a minimum ½" edge distance from board edges to prevent cracking.
Step 4: Tape and Finish the Joints
Apply fiberglass mesh tape over all seams. Embed the tape with MgO-compatible joint compound or thin-set mortar, feathering the edges outward. Allow the first coat to dry fully before applying finish coats. MgO boards can also be finished with tile, paint, or textured coatings after the joints are properly treated.
Step 5: Prime and Finish
Before painting, apply an alkali-resistant primer to the entire surface. This is important because MgO boards have a high pH, which can cause adhesion problems or discoloration with standard latex primers. Once primed, any standard finish paint can be applied.
Common Mistakes to Avoid
- Using standard drywall screws — they corrode and can stain the surface over time.
- Skipping the alkali-resistant primer — leads to paint adhesion failure.
- Over-driving fasteners — reduces holding strength and causes surface damage.
- Not acclimating boards — store boards flat in the installation environment for 24–48 hours before installation.
Final Notes
With the right tools and attention to fastener selection and joint finishing, MgO board wall installation is a straightforward process. The extra preparation steps pay off in a durable, fire-resistant, and moisture-tolerant wall assembly that outperforms standard drywall in demanding conditions.