Steel beams are rolled at steel mills, then cut, drilled, welded and delivered by fabricators. Only a handful of mills in North America roll wide-flange (W) beams, and the beams sold in Ontario often come from mills that certify the same steel to both Canadian and US grades. Algoma Steel, the best-known integrated mill in Ontario, describes itself as a producer of sheet and plate, not beams. Most buyers never deal with a mill at all: they buy from a service centre or a fabricator.
If you searched for "I-beam manufacturers" or "steel column manufacturers" you probably want one of two things: to know who rolls the steel, or to find someone who will make your beam or post. This post covers both.
Who rolls structural steel in North America
These are producers that publicly describe making structural shapes or HSS. It is not a complete list, and mills change what they roll over time, so check current producer literature if a particular mill matters to your project.
| Producer | What it says it makes | Where |
|---|---|---|
| Nucor-Yamato Steel | Wide-flange beams, H-piling, sheet piling, standard I-beams, channels and other structural shapes. Describes itself as the largest structural steel mill in the Western Hemisphere. | Blytheville, Arkansas |
| Gerdau | Wide-flange beams from 4 to 36 inches deep, made at three electric arc furnace mills in North America. Also rebar, merchant bar and other long products. | Mills across North America, including Canadian mills in Whitby, Ontario and Selkirk, Manitoba |
| Steel Dynamics | Lists structural steel beams and shapes among its steel products | United States |
| Atlas Tube (Zekelman Industries) | Steel HSS, pipe piles and mechanical tubing | Mills in the US and in Harrow, Ontario |
| Algoma Steel | Hot and cold rolled sheet and steel plate | Sault Ste. Marie, Ontario |
A few points to take from the table:
- Beams and plate come from different mills. A fabricated beam often combines a W-shape from a structural mill with base plates, cap plates and stiffeners cut from plate that may come from a plate producer such as Algoma.
- HSS is a separate product line. Tube mills like Atlas Tube make the square, rectangular and round sections used for posts and columns. Our explainer on what HSS steel is covers how tube is made.
- Multi-certified steel is normal. Nucor-Yamato, for example, describes its wide-flange mill certificates as listing ASTM A992, ASTM A709 and CSA G40.21 grades together, so one beam can meet a Canadian and a US specification at once. Our post on steel channel grades explains how to read those grades.
For rebar, which is a different set of mills, see who makes rebar in Canada.
How a steel beam is made at the mill
Modern structural mills mostly use electric arc furnaces that melt recycled scrap steel. The molten steel is refined to the right chemistry, cast into a semi-finished shape, then reheated and passed back and forth through rolling stands that squeeze it into the final W profile: two flanges joined by a web. The rolled section is cooled, straightened and cut into long mill lengths.
What leaves the mill is plain stock: a beam of a given designation and grade, in a long length, with a heat number that ties it to a mill test certificate. It has no holes, plates, connections or camber unless the mill offers those as extras. Everything that makes it fit your building happens later.
Mills, service centres and fabricators: who does what
| Company type | What it does | Who buys from it |
|---|---|---|
| Mill | Melts and rolls steel into beams, plate, tube or bar in long lengths and large tonnages | Service centres and large fabricators |
| Service centre (steel yard) | Stocks mill products, cuts to length, sometimes drills or burns simple parts | Fabricators, trades with their own shops, some contractors |
| Fabricator | Details the job, then cuts, drills, fits, welds, finishes and marks each piece to shop drawings, and delivers | Contractors, builders, homeowners, owners |
| Erector | Lifts and connects the steel on site (some fabricators also install) | General contractors and owners |
Our guide to buying structural steel in Ontario goes deeper into how an order moves through these layers, and where to buy steel beams in Ontario compares a yard with a fabricator for a single beam.
The short version: if you need a beam for a house or a building, the company that "makes" it for you is the fabricator. The mill made the steel. The fabricator makes it into your beam, with bearing plates, bolt holes, connections and camber where the drawings call for them.
Columns, posts and lally columns
The same split applies to columns and posts.
- Steel columns in commercial buildings are usually W-shapes or HSS from the mills above, fabricated with base plates, cap plates and connection material.
- Basement posts are typically HSS or round steel tube with plates welded on, made by a fabricator to suit the beam above and the footing below. See HSS steel posts for basements and decks.
- Lally columns are round steel basement columns. The name comes from an early patented concrete-filled column and is now used for almost any round steel post, filled or hollow. Our explainer on what a lally column is covers the history and what you will find in Ontario houses.
- Adjustable steel columns (teleposts) are manufactured products sold with a rated load. The Ontario Building Code limits how and where they can be used as permanent supports; see adjustable steel columns and teleposts.
So a search for "lally column manufacturers" or "steel post manufacturers" usually ends at a fabricator or supplier who makes the finished post, not at a mill.
How to tell where your steel came from
If origin matters (for a project specification, a trade question or plain curiosity), the paperwork tells you.
- Ask for the mill test certificate (also called a mill test report or MTR). It names the producing mill, the heat number, the grades the steel is certified to, and the measured chemistry and mechanical properties. Many certificates also state where the steel was melted and manufactured.
- Match the heat number. Mills mark each piece or bundle with its heat number, and a good fabricator keeps that traceability through cutting and fabrication when the job requires it.
- Check the grade against the drawings. For W-shapes in Canada, drawings typically call for a CSA G40.21 grade such as 350W or 345WM, or an ASTM grade the engineer has accepted. The certificate should show it.
Trade measures also affect where steel comes from and what it costs. Canada's counter-tariffs on US steel, and its import quotas, are covered in our update on steel price increases and tariffs in Canada. If your project has a domestic-content or origin requirement, raise it before the steel is ordered, not after it arrives.
What to look for in the company that makes your beam
Since the fabricator is the one turning mill steel into your beam or column, that is where the quality questions belong:
- Welding certification. In Canada, shops that weld structural steel are certified by the Canadian Welding Bureau. Our post on why to hire a CWB certified fabricator explains what that covers.
- Shop drawings. Ask who prepares them and who checks them against the structural drawings.
- Material traceability. Can they supply mill certificates for your job if the specification requires them?
- Delivery and installation. Can they get the steel to your site when your crew is ready, and do they install or hand off to an erector?
For the full checklist, see how to choose a structural steel fabricator in Ontario.
Getting a beam or column made in Ontario
We are a fabricator: we supply wide-flange beams, HSS posts, plates and channels, fabricated to your drawings with CWB certified shop welding and in-house shop drawings, and we deliver across the GTA and Ontario. We also supply and install structural steel, including basement beams and posts. Send your drawings for a free take-off and quote, or see the steel beams, posts and plates we supply.
Frequently asked questions
Are steel I-beams made in Canada?
Wide-flange beams are rolled at a small number of large structural mills in North America, and beams sold in Ontario often come from mills that roll for both the Canadian and US markets. Algoma Steel, Ontario's best-known integrated mill, describes its products as sheet and plate, not beams. The mill certificate for your beam shows where it was made.
Who makes HSS in Canada?
Atlas Tube, part of Zekelman Industries, lists a mill in Harrow, Ontario that makes steel HSS, pipe piles and mechanical tubing. Tube mills elsewhere in North America also ship into Canada.
Can I buy a steel beam directly from the mill?
Mills sell in large tonnages and full mill lengths, mostly to steel service centres and fabricators. A homeowner or contractor buys through a service centre or a fabricator, which cuts, drills and delivers the beam.
Who makes lally columns and steel posts?
The tube or pipe comes from a tube mill. The finished post, with its base and cap plates, is made by a fabricator or a post manufacturer. Adjustable teleposts are factory products sold with a rated load on the label.
