Introduction
Magnesium oxide board, commonly known as MgO board, has gained popularity in modern construction thanks to its fire resistance, strength, and eco-friendly nature. Contractors often choose it as an alternative to traditional gypsum or cement boards for walls, ceilings, and flooring.
However, like any building material, MgO boards are not free from drawbacks. Over the years, architects and builders have reported several problems during installation and long-term use. While these issues don’t necessarily outweigh the benefits, they are important to understand before starting a project.
This article highlights the 5 common problems and provides practical solutions to avoid them. By knowing the risks and applying the right strategies, builders can maximize the benefits of MgO boards while minimizing potential setbacks.
1. Sweating and Moisture Problems
Why It Happens
One of the most common problems is its tendency to absorb moisture. Moisture-related problems are particularly associated with some MgCl₂-based boards. In poorly ventilated or high-moisture environments, MgO boards with excessive soluble chloride content may experience moisture migration to the surface, resulting in “sweating” or other salt-related issues. This is why the chemical composition and chloride content of an MgO board should be verified before purchase.
Potential Risks in Construction
Paint or wallpaper peeling off walls
Joint compounds losing adhesion
Structural instability if the board swells or softens
For projects like bathrooms, kitchens, or basements, this moisture issue becomes even more critical. If not handled properly, it can shorten the building’s service life and increase maintenance costs.
How to Prevent or Solve
Use MgO boards with lower chloride content, ideally tested for moisture resistance.
Apply waterproof sealants or coatings before finishing the surface.
Ensure good ventilation during installation and in the building’s design.
Avoid exposing the boards to direct rain or water contact before they are fully sealed.
2. Chloride-Related Metal Corrosion
Interaction with Chloride Content
Another notable issue is the potential corrosion of nearby metal components. Some MgO boards, especially those made with magnesium chloride, can release chloride ions over time. When these ions come into contact with steel or aluminum fasteners, screws, or frames, they may trigger rust and corrosion.
Problems in Long-Term Durability
Weakening of metal fasteners, reducing structural integrity
Stains on walls or ceilings caused by rust
Increased maintenance costs due to frequent repairs
Possible safety hazards in load-bearing applications
These problems often appear months or even years after installation, making them easy to overlook during initial construction.
Solutions and Better Practices
Choose MgO boards with low or zero chloride content
Use corrosion-resistant fasteners such as stainless steel or galvanized screws.
Apply protective coatings to any exposed metal near the MgO board.
Store boards in dry conditions before installation to reduce chloride migration.
3. Cracking, Warping and Dimensional Changes
Causes of Structural Instability
Uneven drying or curing during production
Improper storage or handling before installation
Exposure to sudden temperature or humidity changes
Over-tightening screws or poor installation techniques
Even minor cracks can compromise the aesthetic and structural integrity of a project, especially in visible areas like ceilings or decorative walls.
Common Cases in Flooring and Walls
Floorboards that warp due to moisture accumulation under the surface
Wall panels that crack along joints or edges
Ceilings showing hairline cracks after long-term environmental stress
These cases highlight the importance of careful handling and proper installation techniques to reduce the risk of defects.
How to Minimize These Issues
Store MgO boards flat in a dry, ventilated area before use.
Allow boards to acclimate to the room’s temperature and humidity before installation.
Avoid over-tightening screws; use recommended fasteners and spacing.
Apply joint compounds and coatings evenly to prevent uneven expansion or contraction.
By following these practices, builders can avoid most cracking and warping issues, ensuring a smooth and durable finish.
4. Poor Adhesion with Paints and Finishes
Adhesion Challenges with Paints and Coatings
While MgO boards are strong and fire-resistant, they can sometimes show poor adhesion with certain paints, coatings, or adhesives. For example:
Some water-based paints may peel off
Decorative films or laminates may not stick evenly
Oil-based finishes can take longer to cure or require special primers
These challenges can affect both aesthetics and long-term durability.
Issues When Applying Decorative Films
For interior designers and contractors, decorative finishes like wallpapers or PVC films can be particularly tricky:
The board’s surface may be too smooth or chemically reactive for standard adhesives
Improper priming may lead to bubbles, peeling, or uneven textures
Certain coatings may react with residual chloride in the board, causing discoloration
Recommended Alternatives
Apply a suitable primer designed for MgO surfaces before painting or laminating
Test adhesive compatibility on a small panel before full application
Consider water-resistant or specialized finishes that bond better with MgO boards
Consult the manufacturer’s guidelines to select compatible materials
By carefully choosing finishes and following proper preparation steps, builders can achieve smooth, long-lasting results without damaging the board.
5. Inconsistent Quality Between Manufacturers
Why Quality Varies
Differences in raw material purity, especially magnesium oxide and chloride levels
Variations in production processes and curing techniques
Lack of standardized testing for moisture resistance and durability
Even boards that appear similar can perform very differently under the same conditions, which can be frustrating for builders relying on predictable results.
Risks of Using Low-Quality Boards
Higher likelihood of moisture absorption and swelling
Increased cracking or warping
Faster corrosion of metal components
Poor adhesion with finishes, affecting aesthetics
Higher maintenance and replacement costs
Tips for Choosing Reliable Suppliers
Source boards from reputable manufacturers with proven track records
Request material test reports or certifications
Inspect boards for uniform thickness, surface smoothness, and color consistency
Order sample panels before committing to bulk purchases
Final Thoughts: Choosing MgO Board Wisely
While MgO boards offer excellent fire resistance, strength, and eco-friendly benefits, they are not without challenges. Understanding the common problems—moisture absorption, metal corrosion, cracking and warping, limited finish compatibility, and inconsistent quality—can help builders make informed decisions and avoid costly mistakes.
The key to maximizing the benefits of MgO boards lies in careful selection, proper installation, and adherence to manufacturer guidelines. Choosing boards with low chloride content, using corrosion-resistant fasteners, ensuring correct storage, and testing finishes are all practical steps to minimize risks.
To help avoid these common issues, contact our team today. We provide high-quality MgO boards, technical support, and guidance to help you achieve safe, durable, and visually appealing results every time.
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