# Construction Boilermaker (428A)

## Fast facts

| Trade code | 428A |
| --- | --- |
| 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 | 198 (reported in Ontario's apprenticeship dataset) |
| Approved sponsors | 2 |
| Certifying body | Skilled Trades Ontario |

Last verified August 20, 2026 against the sources listed below.

## What does a construction boilermaker do?

A Construction Boilermaker builds, installs, erects, tests, maintains and repairs all types of boilers, tanks and pressure vessels, and performs all types of structural and plate work on dust, air, gas, steam, oil, water and other liquid-tight pressure vessels.

Skilled Trades Ontario describes the work of this trade as follows:

- works from fabrication drawings (prints) to fabricate components from steel or other materials
- uses various metal forming machines such as rotary shears, punch pressess and bending rolls
- tests boiler systems for leaks, defects and other deficiencies to ensure they are operating safely and efficiently
- attaches rigging and works with hoisting devices to lift components into place

## How long is the construction boilermaker apprenticeship?

| Total training hours | 6,600 (about 4 years) |
| --- | --- |
| On the job | 5,880 hours |
| In school | 720 hours |
| In-school levels | 3 |

These hours are set by the Registrar of Skilled Trades Ontario under section 14 of the Building Opportunities in the Skilled Trades Act, 2021.

## What do you study in school for the 428A?

The in-school portion covers, but is not limited to:

- trade practices, such as health and safety documentation
- plant systems and ancillary components
- rigging and hoisting
- crafting and drawing interpretation
- cutting and welding procedures
- applied trade calculations and mathematics
- metallurgy

## Is construction boilermaker a compulsory trade in Ontario?

No. Construction Boilermaker 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](https://ontariocertificationregistry.ca/trades/compulsory/).

## How do you become a construction boilermaker 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:

1. **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.
2. **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.
3. **Receive your Certificate of Apprenticeship.** Skilled Trades Ontario issues it when the program is complete.
4. **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 Construction Boilermaker](https://www.skilledtradesontario.ca/trade-information/construction-boilermaker/). 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 428A?

Yes. Construction Boilermaker 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 428A a Red Seal trade?

Yes. Construction Boilermaker 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 Boilermaker, has 120 multiple-choice questions, each with four possible answers and exactly one correct answer.

### How the 120 questions are distributed

| Major Work Activity | Questions |
| --- | --- |
| A. Performs common occupational skills | 31 |
| B. Performs rigging and hoisting | 36 |
| C. Completes new construction | 27 |
| D. Peforms repairs, maintenance, upgrading and testing | 26 |

By question type, this trade's exam runs 25 to 35% knowledge and recall, 55 to 65% procedural and application, and 10 to 20% critical thinking.

- [Red Seal exam breakdown for Boilermaker: question counts by task](https://red-seal.ca/eng/trades/boilermakers/exam-information.shtml)
- [Red Seal exam preparation checklist](https://red-seal.ca/eng/resources/preparation-checklist.shtml)
- [How to register for a Red Seal exam](https://red-seal.ca/eng/resources/register.shtml)

## 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](https://www.skilledtradesontario.ca/experienced-workers/trade-equivalency-assessment/).

## Certification is not the only paperwork

A Certificate of Qualification covers the person. Running a business in the trade carries its own obligations: many Ontario municipalities require a contractor licence on top of personal certification, and construction employers must complete WSIB registration before work begins. Both are indexed on our sister site: [municipal contractor licensing requirements by city](https://ontariotraderegistry.ca/licensing/) and [WSIB Form 1000, registration of constructors and employers](https://ontariotraderegistry.ca/compliance/wsib-form-1000/), on Ontario Trade Registry.

## What does a construction boilermaker earn in Ontario?

| Median wage | $48.21 per hour |
| --- | --- |
| Low | $31.21 |
| High | $54.21 |
| Occupation measured | Boilermakers (NOC 72103) |
| Reference period | 2023-2024 |

Published by Employment and Social Development Canada through Job Bank, for Ontario as a whole. Read it as the pay range for the occupational group this trade belongs to, not a guaranteed rate: one NOC code can cover more than one trade, and wages vary by region, employer and experience.

## Is the 428A recognised outside Ontario?

This trade has been part of the Interprovincial Red Seal Program since 1976. 10 of Canada's 13 provinces and territories designate it Red Seal: AB, BC, MB, NB, NL, NS, ON, PE, QC, SK, Ontario among them. Its National Occupational Classification code is 72103, which is how federal labour market data refers to this occupation.

## Where can you train as a construction boilermaker in Ontario?

| Public training providers | 1 colleges deliver the in-school portion |
| --- | --- |
| Approved sponsors | 2 employers registered to train apprentices |
| Apprentices in training | 198 |

Counts are from Ontario's published apprenticeships dataset. A sponsor is the employer or union that registers and trains the apprentice; you need one before an apprenticeship can start.

## How dangerous is construction work in Ontario?

Ontario does not publish injury figures per trade, only by sector. In 2024 the Ministry of Labour recorded 18 worker fatalities and 442 critical injuries under the construction health and safety program. See [the ten-year counts and what they leave out](https://ontariocertificationregistry.ca/trades/safety/).

## Related Ontario trades

Other construction sector trades with certification records on this registry:

- [Concrete Pump Operator (637C) certification requirements](https://ontariocertificationregistry.ca/trades/637c-concrete-pump-operator/)
- [Drywall Finisher and Plasterer (453A) certification requirements](https://ontariocertificationregistry.ca/trades/453a-drywall-finisher-and-plasterer/)
- [Electrician - Construction and Maintenance (309A) certification requirements](https://ontariocertificationregistry.ca/trades/309a-electrician-construction-and-maintenance/)
- [Heat and Frost Insulator (253A) certification requirements](https://ontariocertificationregistry.ca/trades/253a-heat-and-frost-insulator/)
- [Heavy Equipment Operator - Dozer (636C) certification requirements](https://ontariocertificationregistry.ca/trades/636c-heavy-equipment-operator-dozer/)
- [OBT-1 Oil Burner Technician 1 fuel certificate requirements](https://ontariocertificationregistry.ca/certificates/obt-1-oil-burner-technician/)
- [All 23 compulsory trades in Ontario](https://ontariocertificationregistry.ca/trades/compulsory/)

## Official verification sources

- Regulation[O. Reg. 876/21, Prescribed Trades and Related Matters (e-Laws)](https://www.ontario.ca/laws/regulation/210876)
- Certifying body[Skilled Trades Ontario: Construction Boilermaker](https://www.skilledtradesontario.ca/trade-information/construction-boilermaker/)
- Act[Building Opportunities in the Skilled Trades Act, 2021 (e-Laws)](https://www.ontario.ca/laws/statute/21b28)
- Wages[Job Bank wage data, Employment and Social Development Canada](https://open.canada.ca/data/en/dataset/adad580f-76b0-4502-bd05-20c125de9116)
- Red Seal profile[red-seal.ca: Construction Boilermaker trade profile](https://red-seal.ca/eng/trades/boilermaker.shtml)
- Participation data[Ontario open data: Apprenticeships dataset](https://data.ontario.ca/dataset/apprenticeships)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.

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Source: https://ontariocertificationregistry.ca/trades/428a-construction-boilermaker/