The Case for Comparing MgO Board and Drywall
Drywall (also called gypsum board or plasterboard) has dominated interior construction for decades. Magnesium oxide board is increasingly positioned as a superior alternative. But is it right for every project? Let's look at the facts side by side.
At a Glance: Side-by-Side Comparison
| Property | MgO Board | Drywall (Gypsum) |
|---|---|---|
| Moisture Resistance | Excellent — inherently moisture-resistant | Poor to moderate — green board offers some resistance |
| Fire Resistance | Excellent — non-combustible, Class A | Good — also non-combustible but can disintegrate under sustained heat |
| Mould Resistance | High — does not support mould growth | Low to moderate — paper facing is susceptible to mould |
| Strength & Hardness | Higher — more impact resistant | Lower — dents and punctures more easily |
| Weight | Heavier per equivalent thickness | Lighter — easier to handle solo |
| Cost | Higher upfront cost | Lower upfront cost |
| Workability | Score-and-snap or saw; slightly harder | Very easy — score-and-snap with minimal effort |
| Availability | Specialist suppliers; growing availability | Widely available everywhere |
Moisture and Wet Areas
This is where MgO board clearly wins. Standard drywall exposed to moisture will swell, crumble, and grow mould. Even moisture-resistant drywall variants have limits. MgO board's mineral composition means it will not absorb water in the same way, making it the logical choice for bathrooms, basements, laundry rooms, and anywhere humidity is a factor.
Fire Performance
Both materials are classified as non-combustible and can be used in fire-rated assemblies. However, MgO board is generally considered to perform better under prolonged fire exposure — it does not release steam (as gypsum does when its chemically bound water vaporises) and maintains structural integrity longer. For critical fire-rated applications, always reference tested assembly data for both materials.
Ease of Installation
Drywall has a well-established advantage here. It's lighter, easier to cut, and any tradesperson is familiar with it. MgO board requires slightly more care when cutting — scoring deeply or using a circular saw with a fine-tooth blade is recommended. Fasteners should be corrosion-resistant (stainless or hot-dipped galvanised), as standard drywall screws can react with MgO compounds over time.
Cost Considerations
MgO board typically costs more per sheet than standard drywall. However, when you factor in the longevity, reduced maintenance, and avoidance of mould remediation costs, the total lifecycle cost can be lower — especially in moisture-prone applications. For high-volume, low-risk interior partitions in dry environments, drywall remains hard to beat on pure economics.
Which Should You Choose?
- Choose MgO board for bathrooms, wet areas, basement walls, fire-rated partitions, coastal or humid climates, and wherever long-term durability matters.
- Choose drywall for standard dry interior partitions where budget is the primary driver and moisture is not a concern.
In many modern builds, contractors use both — drywall in dry interior zones and MgO board wherever performance demands justify the premium. Understanding the trade-offs helps you specify smartly rather than blanket-applying one material throughout.