Fast facts
| Trade code | 420A |
|---|---|
| Sector | Construction |
| Classification | Voluntary trade |
| Certifying exam | Required (O. Reg. 876/21, s. 3) |
| Apprentice to journeyperson ratio | Subject to a ratio (O. Reg. 876/21, s. 4) |
| Red Seal trade | Yes |
| Active apprentices in Ontario | 737 (reported in Ontario's apprenticeship dataset) |
| Approved sponsors | 11 |
| Certifying body | Skilled Trades Ontario |
Last verified August 19, 2026 against the sources listed below.
Is ironworker a compulsory trade in Ontario?
No. Ironworker - Structural and Ornamental is a prescribed trade under section 1 of O. Reg. 876/21, but it is not on the compulsory list in section 2. That means you can legally work in this trade in Ontario without holding a Certificate of Qualification. Certification is voluntary and serves as formal proof of competency to employers and clients.
Voluntary classification only covers certification under the Building Opportunities in the Skilled Trades Act. Specific work within the trade can still require separate licences or permits under other Ontario statutes, so confirm the rules for the actual work being done. The 23 trades where certification is mandatory are on the compulsory trades list.
How do you become a ironworker in Ontario?
The apprenticeship pathway for this trade is administered by Skilled Trades Ontario under section 14 of the Building Opportunities in the Skilled Trades Act, 2021:
- Find a sponsor and register a training agreement. An employer or union sponsor takes you on and the training agreement is registered with the ministry.
- Complete the on the job and in school training. The skills are set out in the trade's Apprenticeship Training Standard, signed off by your sponsor as you demonstrate them, alongside levels of in school theory at a training delivery agent.
- Receive your Certificate of Apprenticeship. Skilled Trades Ontario issues it when the program is complete.
- Pass the certifying exam. This trade has a certifying exam under O. Reg. 876/21, s. 3. Passing it earns the Certificate of Qualification, the voluntary proof of qualification for this trade.
The exact training standard, current curriculum and program details are on the Skilled Trades Ontario page for Ironworker - Structural and Ornamental. On the job hour requirements vary by trade and are not published on this page yet; confirm them in the training standard before signing an agreement.
Is there an apprentice to journeyperson ratio for the 420A?
Yes. Ironworker - Structural and Ornamental is one of the 33 trades that section 4 of O. Reg. 876/21 makes subject to an apprentice to journeyperson ratio. The regulation establishes that a ratio applies, but the numeric ratio itself is not stated in section 4. Confirm the current ratio with Skilled Trades Ontario before registering an additional apprentice, because it limits how many apprentices a sponsor may train at once.
Is the 420A a Red Seal trade?
Yes. Ironworker - Structural and Ornamental participates in the Interprovincial Red Seal Program, the national standard for the trade across Canada, stewarded by the Canadian Council of Directors of Apprenticeship. A Red Seal endorsement on an Ontario Certificate of Qualification means the qualification is recognized in other provinces and territories without re examination, which matters for workers moving between provinces and for employers hiring from outside Ontario.
The Red Seal exam for this trade, written under the national title Ironworker (Structural/Ornamental), has 120 multiple-choice questions, each with four possible answers, distributed across the trade's major work activities per the Red Seal Occupational Standard.
Already experienced? The Trade Equivalency Assessment
Workers with experience from outside Ontario's apprenticeship system, or from another country, can apply for a Trade Equivalency Assessment instead of starting an apprenticeship. Approval requires verifiable evidence of competency in the trade's Training Standard and experience at least equal to the trade's total training time; if approved, you challenge the certifying exam directly. The assessment costs $235 plus HST, and a reassessment with new evidence costs $100 plus HST, per Skilled Trades Ontario's Trade Equivalency Assessment page.
Related Ontario trades
Other construction sector trades with certification records on this registry:
Official verification sources
- RegulationO. Reg. 876/21, Prescribed Trades and Related Matters (e-Laws)
- Certifying bodySkilled Trades Ontario: Ironworker - Structural and Ornamental
- Participation dataOntario open data: Apprenticeships dataset
Classification, exam requirement and ratio status on this page are read directly from O. Reg. 876/21 as consolidated on e-Laws, not from secondary summaries. Facts not yet verified against a primary source are marked as not published rather than estimated.