Yes. In most Ontario houses, the steel lintel over a window or door in brick is angle iron: a hot-rolled steel angle with one leg standing up behind the brick and the other carrying it. But not just any angle will do. Under the 2024 Ontario Building Code it has to be at least the size listed in Table 9.20.5.2.-B for the opening width and veneer type, bear at least 150 mm on masonry, concrete or steel at each end, and be prime painted or otherwise protected from corrosion. A thin angle off a hardware store rack, or a length of scrap of unknown grade, is not the same thing.
Here's what separates an angle that works as a lintel from one that doesn't, and when an angle isn't enough.
Angle iron vs lintel: a shape and a job
The search "angle iron vs lintel" mixes two kinds of word:
- Angle iron (more accurately, steel angle) is a shape: an L-shaped hot-rolled section, described by its two leg lengths and thickness, for example L102 x 89 x 6.4 in millimetres.
- A lintel is a job: whatever spans an opening and carries what's above it. Ontario's code uses "lintel" for wood headers in stud walls as well as steel and concrete lintels in masonry.
So a steel angle lintel is angle iron doing the job of a lintel. Other lintels are W-beams, precast concrete, reinforced masonry or wood. Which one an opening needs depends on what it carries, as our post on steel lintel vs beam explains.
What makes an angle acceptable as a lintel
Article 9.20.5.2 of the 2024 OBC (O. Reg. 163/24, Division B) sets the rules for steel lintels over masonry openings in houses. An angle used as a lintel needs:
- The right size for the span. Table 9.20.5.2.-B lists the minimum angle for each opening width in 70 mm brick, 90 mm brick and 100 mm stone veneer. Table 9.20.5.2.-A covers loose angle lintels in solid masonry walls. A larger angle than the table minimum is always acceptable.
- The right orientation. The tables list the vertical leg first. On an unequal angle, the long leg stands vertical behind the veneer, because the depth of that leg gives the lintel its stiffness. Laid the other way, the same angle sags much more.
- Bearing. At least 150 mm of even, level bearing at each end, on masonry, concrete or steel, under Sentence 9.20.5.2.(3.1). So the angle is at least 300 mm longer than the masonry opening.
- Corrosion protection. Sentence 9.20.5.2.(4) requires steel angle lintels supporting masonry to be prime painted or otherwise protected from corrosion.
- Structural steel. The design notes for the veneer tables assume steel with a 300 MPa yield strength. A structural angle from a steel supplier, with a known grade, meets that. Decorative or light-duty angle of unknown origin may not.
For the full tables and how to read them, see steel lintel sizes under the Ontario Building Code.
The smallest angles the code allows
The most common follow-up question is "how thick does it have to be?" The lightest rows of Table 9.20.5.2.-B answer it:
| Angle (mm) | 70 mm brick | 90 mm brick | 100 mm stone |
|---|---|---|---|
| L89 x 76 x 6.4 | 2.55 | not listed | not listed |
| L89 x 89 x 6.4 | 2.59 | 2.47 | 2.30 |
| L102 x 89 x 6.4 | 2.79 | 2.66 | 2.48 |
| L127 x 89 x 7.9 | 3.47 | 3.31 | 3.08 |
Source: 2024 Ontario Building Code, Division B, Table 9.20.5.2.-B. Maximum allowable spans in metres.
So 6.4 mm (1/4 in) is the thinnest angle in the table, and for standard 90 mm brick the smallest listed angle is an L89 x 89 x 6.4, good up to 2.47 m. Wider openings step up to 7.9 mm, 11 mm and 13 mm angles with longer vertical legs. The metric sizes in the table are the familiar imperial angles: an L89 x 89 x 6.4 is a 3-1/2 x 3-1/2 x 1/4 in angle, an L102 x 89 x 6.4 is 4 x 3-1/2 x 1/4 in, and an L127 x 89 x 7.9 is 5 x 3-1/2 x 5/16 in. An angle sold in imperial sizes is fine as long as its legs and thickness are at least as large as the row you need.
Thin angles in the 3 mm to 5 mm range, common in hardware stores and metal hobby shops, are not on the table at all.
Shortcuts that don't count as a lintel
These come up on renovation jobs and in online forums. None of them is a substitute for a table-sized angle or a designed lintel:
- Thin or undersized angle. An angle thinner or shorter-legged than the table minimum may carry the brick at first and sag over time, cracking the mortar in a stair-step pattern above the opening.
- Flat bar or plate on its own. The table lists angles, and a flat bar laid under brick has very little stiffness. It isn't covered by the tables.
- Unknown or used steel. Salvaged angle may be the right shape but of unknown grade, pitted by rust or bent. If you can't confirm what it is, don't rely on it.
- Two light angles instead of one heavier one. Doubled angles do appear in Table 9.20.5.2.-A for solid masonry walls, where interior and exterior angles each carry part of the wall. Substituting two small angles for a single listed veneer lintel is a design question, not a swap.
- The wrong orientation. An unequal angle installed with the short leg vertical has far less stiffness than the table assumes.
When an angle isn't enough
Angle iron is the right lintel for brick and stone veneer over most windows and doors. It stops being enough when:
- The opening is too wide. The largest angle in Table 9.20.5.2.-B, an L178 x 102 x 13, reaches 4.59 m in 90 mm brick. A 16 ft garage door needs a W-beam with a welded plate under Table 9.20.5.2.-C, supported on steel columns, or an engineered lintel. See steel lintels over garage doors.
- The lintel carries floors or a roof. Veneer angles carry only the masonry. If the opening is in a load-bearing wall, it needs a header or beam for those loads as well.
- The wall is solid masonry with floor loads. Table 9.20.5.2.-A sizes loose angles for solid walls and the floor load they carry, with double angles in thicker walls. Outside that table, the lintel is designed.
- It's a concrete block wall. Block walls have their own lintel options, covered in steel lintels for concrete block walls.
Installing or replacing a lintel in an existing wall means supporting the masonry above first, and widening an opening is a structural change that needs a permit. That work is for a mason or contractor working to the drawings.
Ordering angle lintels
To quote angle lintels accurately we need the masonry opening widths, the veneer type and thickness, the angle sizes from your drawings or the code table, the lengths including bearing and any finish requirement. We supply angle lintels for masonry openings, cut to length and punched or welded as needed, and fabricate beam lintels with welded plates for wider openings.
Send us your opening sizes or drawings for a quote, or see our steel products for the lintels, beams and plates we supply.
Frequently asked questions
Can angle iron be used as a lintel?
Yes. In Ontario houses, the steel lintel over a window or door in brick veneer is almost always a hot-rolled steel angle. It has to be at least the size listed in the Ontario Building Code tables for the span and veneer, bear at least 150 mm at each end and be primed or otherwise protected from corrosion.
What is the difference between angle iron and a lintel?
Angle iron is a shape: an L-shaped steel section. A lintel is a job: the member that spans an opening and carries what is above it. An angle becomes a lintel when it is sized and installed to carry masonry over an opening.
How thick does a steel angle lintel need to be for brick?
The thinnest angles listed in Table 9.20.5.2.-B of the 2024 Ontario Building Code are 6.4 mm (1/4 in) thick, and wider openings call for 7.9 mm, 11 mm or 13 mm angles. For standard 90 mm brick, the smallest listed angle is an L89 x 89 x 6.4, good for spans up to 2.47 m.
Which way does an angle iron lintel go?
The code table lists the vertical leg first. On an unequal angle the longer leg stands vertical behind the veneer, and the shorter leg sits horizontal under the brick.
