MGO Exterior Wall Sheathing Behind Cladding Systems

MGO (Magnesium Oxide) exterior wall sheathing is a high-performance inorganic board, which is installed between the exterior wall frame and the exterior cladding. It undertakes critical functions such as structural support, fire resistance, moisture resistance, mold resistance, wind resistance and seismic performance, making it an ideal substrate for modern curtain wall and cladding systems.

 

MGO exterior wall sheathing is an inorganic cementitious board, mainly composed of magnesium oxide (MgO) and magnesium sulfate (MgSO₄) as binders, fiberglass mesh as reinforcement, and mineral fillers as auxiliary materials.

Its core function is to serve as a structural substrate and protective layer behind the exterior cladding, which can replace traditional materials such as plywood, OSB, cement board and gypsum board.

 

In terms of the wall system layout, its position is as follows: Wall Structure → Insulation Layer → MGO Sheathing → Waterproof Breathable Membrane → Furring/Framing → Exterior Cladding (including stone, metal panel, siding, brick, paint, etc.).

 

The core components of MGO exterior wall sheathing are as follows: Magnesium Oxide (MgO) is the main binder, which provides the board with sufficient strength and excellent fire resistance. Magnesium Sulfate (MgSO₄) is used to regulate the setting process of the board and enhance its overall strength. Premium products adopt chloride-free formulas to avoid efflorescence and corrosion problems.

 

Fiberglass mesh is added in multiple layers to enhance the board's flexural strength, impact resistance and crack resistance. Mineral fillers, such as silica sand and talc, can improve the board's density, dimensional stability and workability.

 

The production process of MGO exterior wall sheathing is as follows: Batching → Mixing → Mesh Laying → Pressing → Curing → Cutting → Finished Product. The standard size of the board is 1220×2440mm (4×8 ft), and the common thicknesses are 6mm, 8mm, 10mm, 12mm and 15mm.

The edge types include square edge, tongue-and-groove (T&G) and shiplap, which are designed to facilitate installation and improve waterproof performance.

 

About MgO Wall Board

Advantage of MGO Board:

1. Fire Resistance (Outstanding Advantage)

Its fire resistance rating reaches Class A1 non-combustible standard, which fully complies with both ASTM E136 and EN 13501-1 standards; moreover, the maximum fire resistance duration can reach 4 hours. At high temperatures, it will not melt, drip, or produce toxic fumes, making it extremely safe. For high-rise buildings and public buildings that require fire separation sheathing, this product can be used directly without additional treatment.

2. Moisture Resistance & Dimensional Stability

Compared with plywood and OSB (Oriented Strand Board), its biggest advantage is that it's not "delicate" when exposed to water-it won't expand, deform, or delaminate and crack. It has low water absorption, is excellent at resisting mold, fungi, and termites, so you don't have to worry about insect infestation. In addition, its thermal expansion and contraction coefficient is much lower than that of wood; after long-term use, it won't warp or crack, and its dimensions remain stable.

3. Structural & Mechanical Properties

It's lightweight yet high-strength, with a density between 0.8–1.25 g/cm³ and a flexural strength of ≥12–15 MPa, which is strong enough. When used as structural sheathing, it can play a role in shear resistance and enhancing lateral stiffness, with good support. Another practical point is its high screw retention-fasteners for exterior wall cladding can be fixed directly into MGO (not just on studs), which simplifies installation and reduces thermal bridges for better energy efficiency.

4. Durability & Weather Resistance

It's very durable, resistant to UV rays, acids, alkalis, and salt spray, so it's ideal for coastal areas and industrial regions. Furthermore, it has a long service life, won't age or powder, and requires almost no maintenance costs later, making it very worry-free.

5. Environmental & Healthy

You can rest assured about this point-it contains no formaldehyde, VOCs (Volatile Organic Compounds), or asbestos, and is harmless to the human body. It consumes little energy during production, and the material itself is recyclable, making it an eco-friendly inorganic material that meets the requirements of green buildings and ensures the health of residents and users.

6. Thermal & Acoustic Performance

It has low thermal conductivity, which can assist in thermal insulation and help save energy consumption for air conditioning and heating. At the same time, it has high density and excellent sound insulation performance, with a sound insulation capacity of ≥35dB, which can effectively isolate external noise and make the interior quieter.

 

 

 

Functions in Cladding Systems

 

Structural Support

• Provides a continuous rigid substrate for wall framing, resisting wind and seismic loads.
• Reliable base for fixing stone, metal panels, fiber cement siding, wood siding, etc.

 

Fire Barrier

• Forms a continuous fire layer behind cladding to prevent vertical fire spread.

 

Moisture & Air Barrier

• Blocks rain and moisture from entering the wall cavity, protecting insulation and structure.
• Works with waterproof breathable membrane to form an efficient weather-resistant barrier.

 

Flat Substrate

• Provides a highly flat surface for cladding installation, reducing leveling work.

 

 

MgO Wall Board Features And Advantages

 

Product Detail：

 

Main Materials: MgO, MgCl2/MgSO4, Glass fiber Mesh

Fire Performance: Non-combustible, No flame spread, No smoke spread,No poisonous gas

Density: 0.8-1.25g/cm3,

Flexural Strength: 8-25Mpa

Impact Strength: ≥3.5 kJ/m2

Moisture Content: ≤8%

Shrinkage: ≤0.3%

Swelling: ≤0.3%

ScrewHolding Capacity: 40-120/(N/mm)

Leachable Chloride : 0.1%(MOS),3%(MOC)

Edge: Square/T&G/Tapered/Beveled

Thickness: 6-15mm

Standard Sizes: 4*8ft/1.22*2.44m(Other sizes can be customized)

Production Capacity: 5000 square meters / day

Remark : The above parameters are acceptable to ODM

 

MgO Wall Board Factory

 

Our Service：

Our production capacity is about 5000 square meters per day. We have strict quality control over our products. We test each batch of products in the laboratory and check each plate before packing. We have a well-established sales team that can answer your questions at any time. We're dedicated to provide the best service possible .

 

FAQ:

1.Can you make products according to our requirements?

A: Of course, we accept OEM/ODM.

2.How do you pack your products?

A: Plywood / Solid wood pallet.

3.How about samples?

A: Free samples with shipping cost.

 

Packing and Shipping of MGO Exterior wall sheathing behind cladding systems

 

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