Debunking 6 Common Structural Welding Myths: What You Need to Know

When it comes to the “bones” of your building—the beams, columns, and lintels that hold everything up—there is absolutely no room for error. Structural welding is a highly regulated trade in Ontario, yet several persistent myths continue to circulate among property owners and contractors.

At Weld Rich & Steel, we believe that transparency is the foundation of safety. Here is the truth behind the 6 most common myths in the structural welding industry.

Myth 1: If a Weld Looks “Clean,” It Is Structurally Sound

Many people believe that a smooth, ripple-like weld (often called “stacks of dimes”) is a guaranteed sign of strength.

• The Reality: Aesthetics can be deceiving. A weld can look perfect on the surface but suffer from a lack of fusion or internal porosity (trapped gas bubbles) underneath.

• The Professional Standard: Structural integrity is about “penetration”—how deeply the weld metal has fused with the base steel. At Weld Rich & Steel, we prioritize the internal bond over surface-level beauty, often using Non-Destructive Testing (NDT) to verify the core strength of critical joints.

Myth 2: Structural Steel Doesn’t Require Preheating in Summer

A common misconception in Toronto is that preheating is only for the winter months.

• The Reality: Preheating depends on the steel thickness and ambient humidity, not just the air temperature. Even on a warm July day, thick structural beams can act as a “heat sink,” cooling the weld too rapidly and causing it to become brittle.

• The Professional Standard: We follow strict CSA W59 guidelines. We use infrared thermometers to ensure the steel is at the correct temperature before the first arc is struck, preventing “delayed cold cracking.”

Myth 3: Any Welder Can Perform Structural Work

Many believe that a general “fabricator” or “handyman with a welder” is qualified to install a load-bearing beam.

• The Reality: In Ontario, structural welding is legally regulated. An uncertified weld on a load-bearing structure can lead to failed city inspections, the denial of insurance claims, and—in the worst-case scenario—structural collapse.

• The Professional Standard: All structural work must be performed by a CWB (Canadian Welding Bureau) certified welder under a registered company. This ensures that the technician has been tested in specific positions (flat, vertical, overhead) and that their equipment is up to code.

Myth 4: Welding is Always Better and Stronger Than Bolting

There is a myth that a “permanent” weld is always superior to a bolted connection.

• The Reality: Engineering is about the right tool for the right job. Bolted connections are often preferred in high-rise construction or areas subject to extreme temperature swings because they allow for thermal expansion and contraction without cracking.

• The Professional Standard: We follow the engineer-of-record’s specifications. If a joint needs to be rigid and monolithic, we weld it. If it needs to “breathe” or allow for easier future disassembly, we use high-strength structural bolts.

Myth 5: On-Site Welding is a Major Fire Hazard for Homes

Homeowners often fear that bringing a welding arc into their basement or onto their porch will inevitably lead to a fire.

• The Reality: While the risks are real, they are completely manageable with professional protocols.

• Hot-work planning: Confirm site authorization, fire-watch arrangements, ventilation and protection of adjacent areas against the applicable requirements for the actual work.

Myth 6: Structural Welding is “Overpriced” Compared to Wood

Some clients believe that a steel beam installation is an unnecessary expense compared to using engineered wood (LVLs).

• The Reality: Steel offers a much higher strength-to-weight ratio. Using steel allows for longer spans and thinner profiles, which means you can have a truly open-concept living space without bulky wooden posts blocking your view.

• Long-term performance: Steel can avoid timber shrinkage, but deflection and movement depend on the entire designed structure, connections and foundation conditions.

The Structural Safety Checklist

Before you hire a welder for your Toronto project, ask these three questions:

1. Certification check: Verify the company’s current CWB certification and the individual qualifications required for the proposed process and position; they are different records.

2. What is your Fire Watch protocol? (Safety is non-negotiable).

3. Do you follow CSA W59 standards? (This is the “Bible” of Canadian structural welding).

Don’t Compromise on the “Bones” of Your Building

Structural welding is a science, not a hobby. By ignoring these myths and focusing on certified expertise, you ensure that your renovation or new build is safe, legal, and built to last.