There is something deeply exciting about building a home. Especially if the home is yours, at the same time, it can feel overwhelming with a bunch of terminology that might be new or even confusing. Understanding each option is important to know the advantages and disadvantages of using a specific material in your build. For this reason, we are going to take a look at the benefits of using steel mesh in construction. Also, steel mesh is referred to as reinforcing mesh or welded wire mesh. So when you are doing your research, you can use multiple terms to get a wide range of information.
What are some Advantages of Steel Mesh?
Corrosion Resistance for Coastal and Inland Climates
- Zinc Coating Protection: Galvanised steel mesh is coated with a layer of zinc, which protects the underlying steel from moisture and oxygen, reducing rust formation.
- Self-Healing Properties: If the coating is scratched, zinc will corrode preferentially, providing sacrificial protection to the steel.
- Suitability for South Africa’s Diverse Climates:
- Coastal regions (e.g., Durban, Cape Town) with high humidity and salt-laden air accelerate rusting in untreated steel. Galvanised mesh provides a practical solution for durability in these regions.
- Inland areas with fluctuating temperatures and occasional heavy rains (e.g., Gauteng, Free State) can cause condensation and corrosion; galvanisation protects mesh reinforcement used in plaster and fencing.
- Extended Lifespan: Properly galvanised mesh can last 20–50 years, depending on local environmental exposure, reducing the need for frequent replacements.
Structural Reinforcement for Concrete and Plaster Applications
- Crack Prevention: Embedded in plaster or concrete, galvanised mesh helps control cracking due to shrinkage, settlement, or temperature fluctuations.
- Enhanced Structural Integrity:
- In plaster, mesh holds the plaster together even if minor cracks develop, maintaining wall integrity.
- In concrete slabs or beams, mesh reinforcement helps distribute loads evenly, increasing tensile strength where traditional rebar is excessive or unaffordable.
- Adaptable to Various Building Methods:
- Suitable for earthbags, straw bales, or alternative buildings, where mesh aids in bonding plaster securely to irregular surfaces.
- Useful in retaining walls for stability in areas prone to soil erosion.
- Local Practice Compatibility: Many South African builders use mesh in ceilings, water tanks, and slab construction, making it a familiar and versatile reinforcement option.
Long-Term Durability and Reduced Maintenance Costs
- Minimizes Repair Frequency: Reduced cracking and corrosion in structures lower the need for continuous patching or re-plastering, which is costly and time-consuming.
- Reduced Rust-Related Failures: Rust expansion in the non-galvanised mesh can crack plaster and concrete, requiring repairs. Galvanised mesh minimises this risk.
- Longer Service Life: Mesh used in fencing, animal enclosures, and protective barriers retains strength and appearance over the years, even with exposure to rain and sun.
- Value for Community Projects: For low-cost housing or NGO-driven builds, using galvanised mesh ensures the structure remains safe and usable longer, protecting the investment of time and resources.
Affordability vs Alternatives in Local Contexts
- Lower Material Costs:
- Galvanised mesh is typically cheaper and easier to handle than heavy rebar in small structures.
- More cost-effective than stainless steel mesh, which is often too expensive for low-cost or community housing.
- Reduced Labour Costs:
- Easier and faster to install due to its flexibility and lightweight.
- Can be tied with wire or nailed onto wooden supports without heavy machinery.
- Widely Available in South Africa:
- Readily found at major suppliers (Steeledale), reducing transport costs for rural projects.
- Balance of Performance and Price:
- Provides necessary structural support while remaining within budget constraints for low-income housing, farm structures, and alternative building projects.
What are some Disadvantages of Steel Mesh?
Limited Lifespan in Harsh Environments
While galvanised coating protects against rust, it can wear off over time, especially in highly corrosive environments (like marine or industrial areas), requiring maintenance or replacement.
Reduced Weldability
The zinc coating can make welding the mesh more difficult or cause defects, which might limit certain fabrication or installation techniques.
Potential for Zinc Coating Damage
The galvanised layer can be scratched or damaged during handling and installation, exposing the steel underneath to corrosion.
Environmental Concerns
The galvanising process involves chemicals and energy consumption that can have environmental impacts compared to non-coated steel.
Thermal Expansion Differences
The zinc layer and steel have slightly different thermal expansion properties, which in rare cases might contribute to micro-cracking or coating failure under extreme temperature changes.
Not Suitable for Extreme Chemical Exposure
Galvanised coatings can degrade faster if exposed to strong acids, alkalis, or other aggressive chemicals.