Magnesium Oxide Sulfate Wall Sheathing Board

Magnesium Oxide Sulfate Wall Sheathing Board (short for MgSO₄ board / Magnesium Sulfate board) is a new generation of chloride-free, high-performance inorganic fireproof building board. It uses magnesium sulfate (MgSO₄) instead of magnesium chloride (MgCl₂) as the cementitious system, completely eliminating issues like halogen return, efflorescence, and metal corrosion. It combines Class A fire resistance, waterproofing, high strength, light weight, and eco-friendly formaldehyde-free performance, making it an ideal wall sheathing board for steel structures, humid environments, and high-safety buildings.

 

MgSO₄ board is made from high-purity light-burned magnesium oxide (MgO) and magnesium sulfate (MgSO₄) as core cementitious materials, mixed with fiberglass mesh, plant fiber, perlite, modifiers, etc. It is produced through mixing, rolling, forming, and curing. It is specially used for wall sheathing, exterior wall siding, interior wall substrates, etc.

 

Difference from Traditional MgCl₂ MGO Board

Item	Magnesium Sulfate Board (MgSO₄)	Magnesium Chloride Board (MgCl₂)
Core Binder	Magnesium Sulfate (MgSO₄)	Magnesium Chloride (MgCl₂)
Chloride Content	≤0.012% (nearly chloride-free)	≥5% (easy halogen return)
Halogen Return / Efflorescence	No halogen return, no efflorescence	Easy in humid environment
Metal Corrosion	No corrosion, protects steel structure	Corrodes steel, keels, metal parts
Water Resistance	≥90% strength retention after 7‑day soaking	Softens and loses strength in water
Application	Humid, steel structure buildings	Dry environments only

 

 

Raw Materials & Production Process

Main Raw Materials

• Cementitious: High-purity light-burned MgO, magnesium sulfate heptahydrate (MgSO₄·7H₂O)
• Reinforcement: Fiberglass mesh, plant fiber / wood fiber
• Fillers & Modifiers: Perlite, talc powder, polymer modifiers
• Additives: Formaldehyde-free, asbestos-free, heavy-metal-free

Production Flow

• Raw material proportioning
• Slurry mixing
• Lay mesh & forming
• Cutting & curing
• Sanding & finishing

 Performance

Physical Properties

• Standard Size: 1220mm × 2440mm (4ft × 8ft)
• Thickness: 5mm, 6mm, 8mm, 10mm, 12mm, 15mm, 20mm
• Density: 1000–1400 kg/m³
• Moisture Content: ≤8%

Mechanical Properties

• Flexural Strength: 12–18 MPa
• Compressive Strength: ≥25 MPa
• Impact Strength: ≥2.0 kJ/m²
• Screw Withdrawal: ≥1200 N

 Fire Performance

• Fire Rating: Class A1 Non‑combustible
• Fire Resistance: 2–3 hours
• Fire Behavior: No smoke, no toxicity, no dripping

Waterproof & Moisture Resistance

• Water Absorption: ≤15%
• 7‑day soaking: No expansion, no warping, no delamination
• Suitable for bathrooms, basements, coastal buildings

 Environmental & Durability

• Formaldehyde: E0 level (≤0.03 mg/m³)
• Asbestos‑free, VOC‑free
• Freeze‑thaw resistant, anti‑aging, mildew‑proof, termite‑proof
• Service life: ≥50 years

Sound & Thermal Insulation

• Sound Insulation: 30–45 dB
• Thermal Conductivity: 0.08–0.12 W/(m·K)

 

 

Main Advantages

• Chloride‑free, no halogen return, no metal corrosionIdeal for steel structure buildings.

• Class A1 fireproof, high safetyNon‑toxic, non‑flammable, high fire resistance.

• Excellent water resistanceStable in long‑term humid environments.

• High strength & light weightEasy to cut, drill, nail, install.

• Eco‑friendly & healthyFormaldehyde‑free, asbestos‑free, non‑toxic.

• Long durability & low maintenance

 

Product details

Typical Applications

• Exterior wall sheathing & siding
• Interior wall substrate & drywall
• Light steel keel partitions
• Basements, garages, bathrooms, kitchens
• Coastal & high‑humidity buildings
• Steel structure residential & commercial buildings
• Fire partitions, ceiling boards, prefab houses

 Installation Guide

Keel spacing ≤ 400 mm

Screw spacing: 150–200 mm

Joint gap: 3–5 mm with joint compound & fiber tape

Can be painted, wallpapered, tiled, laminated

 

 Comparison with Traditional Boards

Board Type	MgSO₄ Board	Gypsum Board	Fiber Cement Board	MgCl₂ Board
Fire Rating	A1	Flammable	A1	A1
Water Resistance	Excellent	Poor	Good	Medium
Halogen Return	No	No	No	Severe
Eco-friendly	Excellent	Medium	Good	Good
Weight	Medium	Light	Heavy	Medium
Workability	Excellent	Excellent	Poor	Good
Humid Use	Best	No	Yes	No
Steel Structure	Perfect	Good	Good	Not recommended

 

About The Factory：

 

Our Service：

1. Reply your enquiry in 24 working hours.

2. Experienced staffs answer your questions in professional and fluent English.

3. The dimensions can be customized.

4. Special discount and protection of sales are provided.

5. Be the best magnesium oxide board supplier in China.

 

Company Advantage (Why choose us)：

 

Specializing in the durability of building materials, we have established ourselves as a leading provider in the local fireproof flooring sector by offering robust, fire-resistant boards.

 

Our rigorous full-process quality control system ensures consistency at every stage:

   1. Incoming Quality Control (IQC) for raw materials to verify baseline standards

   2. In-Process Quality Control (IPQC) with continuous monitoring of critical production phases

   3. Outgoing Quality Control (OQC) covering final cutting, packaging, and comprehensive checks before dispatch.

 

All our finished products adhere to national and industry benchmarks, undergoing thorough testing against standards such as GB/T 33544 or T/CMMA8-2020. We also accommodate custom testing requirements specified by clients, ensuring that only inspected and certified products are released for delivery. This commitment to quality has solidified our reputation for reliability in fireproof building solutions.

 

Packing and Shipping:

Packaging and Shipping of Mold resistant wall panels

 

FAQ:

Q: What is your delivery time?

A: 1 month after receiving the deposit.

Q: Can you customize products?

A: Yes, we can cut any size as needed.

Q: What is your MOQ? Can we order a mix of different sizes?

Answer: Yes. The MOQ is 100 pieces and mixed loading is also acceptable.

 

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