Hot-Dip Galvanizing (HDG): 5 Reasons It’s Essential for Ontario’s Climate

Hot-dip galvanizing (HDG) is one of the most dependable methods for protecting structural steel exposed to Ontario’s outdoor conditions. With frequent freeze–thaw cycles, moisture, and chloride exposure from de-icing salts, corrosion can progress quickly if steel is left unprotected. HDG provides a long-lasting, uniform zinc coating that significantly improves the durability and performance of exterior steel elements.

In this article, we outline five key reasons HDG remains a preferred corrosion-protection method for structural applications across Ontario.

© by Wertuose

Why Hot-Dip Galvanizing Matters for Ontario’s Climate

Ontario’s temperature fluctuations and winter salting practices create an aggressive environment for exposed steel. Unprotected surfaces can experience:

• Accelerated rust formation

• Reduced structural capacity over time

• Increased maintenance costs

• Premature deterioration of connections and anchors

HDG counters these risks with a bonded zinc layer designed to perform under challenging weather and chemical exposure.

1. Metallurgical Bond for Superior Corrosion Resistance

HDG is produced by immersing cleaned steel into molten zinc, forming a metallurgical bond rather than a surface coating. This zinc layer:

• Acts as a continuous barrier against moisture and salts

• Provides sacrificial (cathodic) protection when abrasion occurs

This dual mechanism offers reliable corrosion resistance, making HDG suitable for long-term outdoor use throughout Ontario.

2. Ideal for Exposed Structural Components

HDG is commonly specified for structural elements that operate outdoors or in harsh industrial environments, including:

• Foundation anchors, tie-backs, and helical piles

• Exterior ladders, stairs, guardrails, and walkways

• Rooftop equipment frames for HVAC or solar systems

• Balcony supports, platforms, and retaining-wall accessories

These components benefit from HDG’s uniform coverage and minimal maintenance requirements.

3. Meets CSA G164 and ASTM A123 Standards

HDG coatings follow recognized standards such as CSA G164 and ASTM A123, which define zinc thickness, coating quality, and inspection requirements. Compliance with these standards ensures predictable performance, consistent adhesion, and documented quality control.

Depending on environmental exposure, galvanized steel typically provides 30–70 years of service life with minimal upkeep.

4. Outperforms Paint and Thin Zinc Coatings

Paint systems or thin zinc layers (e.g., electroplating) can crack, peel, or deteriorate under freeze–thaw conditions. Once the coating is compromised, corrosion progresses rapidly.

HDG offers:

• A bonded, abrasion-resistant zinc layer

• Strong performance under thermal cycling

• Full coverage including edges, corners, and interior surfaces of hollow sections

This durability makes HDG more reliable for Ontario’s exterior conditions than paint-only systems.

5. Proven Long-Term Performance in Structural Applications

Structural engineers specify HDG when corrosion risk is high or long service life is required. Its predictable behaviour helps maintain the reliability of exterior elements without frequent recoating or inspection. This makes HDG a practical and cost-effective choice for many outdoor steel systems across Ontario.

Conclusion

Hot-dip galvanizing provides robust and long-lasting corrosion protection for structural steel exposed to Ontario’s climate. Its metallurgical bond, compliance with CSA/ASTM standards, and performance under freeze–thaw and chloride exposure make it an effective option for elements such as anchors, exterior platforms, and rooftop frames.

At Parsways Inc., our engineers incorporate HDG where required to ensure durable, low-maintenance performance for structural systems operating in harsh outdoor environments.

Co-authored by Hoda Rajaeizadeh and Negin Amani.

---

FAQs

1. How long does hot-dip galvanized steel last in Ontario’s climate?

HDG typically provides 30–70 years of service life in Ontario, depending on exposure conditions and maintenance. Its metallurgical bond ensures stable long-term corrosion resistance.

2. Is HDG suitable for structural elements exposed to de-icing salts?

Yes. HDG performs well in environments with chlorides from road salts and winter operations, making it ideal for foundations, exterior platforms, and rooftop steel.

3. What standards apply to hot-dip galvanizing in Ontario?

HDG must comply with CSA G164 and ASTM A123, which define zinc thickness, coating quality, and inspection requirements for consistent performance.