Load-Bearing Performance of Magnesium Oxide Board (MGO Board) as Building Materials
Jul 13, 2026
1. Basic Material Definition
Magnesium oxide board (short for MGO board / magnesium cement board, commonly known as magnesium board) is a fireproof inorganic composite board made of magnesium oxide, magnesium chloride, perlite, glass fiber mesh and filling materials. Its load-bearing capacity is determined by raw material ratio, core density, fiber reinforcement and board thickness.
2. Core Load-Bearing Index Terminology
Mechanical Load Indicators
Bending Load / Flexural Load The maximum vertical force the board can bear under simply supported bending state, the core index for floor, ceiling and wall panel load evaluation.
Uniformly Distributed Load (UDL) Even load spread over the whole board surface, used for ceiling load standard testing.
Concentrated Load / Point Load Local force applied on a single point of the board, simulating footstep impact, equipment local pressure.
Flexural Strength / Modulus of Rupture (MOR) Unit: MPa; reflects anti-bending mechanical property, higher value means stronger load resistance.
Elastic Modulus (Modulus of Elasticity) Characterizes board rigidity; high elastic modulus reduces deflection under load.
Deflection Vertical deformation under load; building codes set maximum allowable deflection to avoid cracking.
Impact Load Resistance Anti-breakage performance under sudden impact load, auxiliary load-bearing safety indicator.
Compression & Tensile Indicators
Compressive Strength: Anti-crushing capacity under vertical extrusion, critical for bearing partition wall load.
Tensile Strength: Anti-splitting tension resistance, mainly reinforced by alkali-resistant glass fiber mesh inside MGO boards.
3. Key Factors Affecting Load-Bearing Capacity
Board Thickness Thicker MGO boards have higher bending load and rigidity. Common specifications: 6mm/8mm (ceiling, light partition), 12mm/15mm (wall cladding), 18–30mm (load-bearing floor substrate).
Internal Fiber Reinforcement Double-layer alkali-resistant fiberglass mesh greatly improves tensile and bending load performance; single-layer mesh boards have weak anti-cracking and load capacity.
Board Density & Formulation High-density compact MGO core delivers higher compressive strength; low-density lightweight foamed magnesium boards are only for non-load-bearing decorative layers.
Support Spacing of Keel / Joist Smaller keel spacing improves overall load-bearing performance. Excessive span will cause excessive deflection or board fracture under standard load.
Installation Fixing Method Screw spacing, adhesive bonding, and edge reinforcement all affect the overall load-bearing system stability of the assembled magnesium board structure.
4. Load-Bearing Classification by Application Scenarios
Non-load-bearing MGO Boards
Thickness: 3–10mm
Usage: Ceiling veneer, inner wall decorative panel, fireproof liner
Load limit: Only bear self-weight and minor surface decoration load; cannot bear human walking or heavy equipment.
Semi-load-bearing MGO Boards
Thickness: 12–18mm
Usage: Indoor partition wall substrate, secondary overhead ceiling
Load capacity: Resist wall hanging load (cabinets, air conditioners); not suitable for pedestrian floor use.
Full-load-bearing MGO Floor Boards
Thickness: 20–30mm high-density reinforced magnesium board
Usage: Steel structure floor, loft mezzanine, prefabricated walkable floor
Standard load compliance: Meet residential uniform live load requirement (2.0kN/㎡ or above) for pedestrian activity.
5. Standard Test & Safety Requirements
Test condition: Simply supported span test specified in international building material standards.
Failure judgment: Visible crack, permanent residual deflection exceeding allowable value, or board fracture under rated load.
Safety margin: Engineering design requires actual working load ≤ 60–70% of board ultimate bending load to prevent long-term creep deformation.
Creep property note: Long-term continuous heavy load will cause slow permanent deflection of magnesium cement substrate; load-bearing floor boards must use high-density low-creep formulations.
6. Limitations in Load-Bearing Design
MGO board is a brittle inorganic plate; poor resistance to local concentrated point load without keel support.
Cannot be used as independent load-bearing structural slab without supporting joists/steel keels.
Low-density lightweight magnesium boards shall never be used for walkable floor load-bearing layers.
Humid environment may reduce interface bonding strength, indirectly lowering overall assembly load performance.
7. Common Engineering English Sentences for Reference
Magnesium oxide board's load-bearing performance is primarily governed by its thickness, density and fiberglass reinforcement layers.
For pedestrian mezzanine floors, high-density MGO boards with thickness over 20mm are required to meet standard live load demands.
Excessive joist spacing will increase board deflection and reduce the overall allowable uniformly distributed load.
Single fiberglass mesh magnesium boards are only applicable to non-load-bearing decorative ceilings.
