Steel Lintels Over Garage Doors: Sizes and Options

A single garage door in a brick veneer house usually takes one steel angle lintel sized from Table 9.20.5.2.-B of the 2024 Ontario Building Code, such as an L127 × 89 × 7.9 for a 9 ft (2.7 m) opening in 90 mm brick. A 16 ft double door is wider than any angle in that table can span in 90 mm brick or stone, so it normally gets a wide-flange beam with a welded plate under Table 9.20.5.2.-C, supported on steel columns, or an engineered lintel.

Garage doors are the widest openings in most houses, which is why their lintels sag, rust and crack the brick more often than the ones over windows. This guide covers the garage-specific cases. For the full lintel tables and how to read them, see our guide to steel lintel sizes under the Ontario Building Code.

What a garage door lintel actually carries

In a typical Ontario house the garage front is a wood-framed wall with brick or stone veneer on the outside. Two separate pieces span the door opening:

• A header in the wood wall carries the roof, and any floor above. It is sized by the designer like any other header or beam.
• A steel lintel in the veneer carries only the brick or stone above the opening. This is usually a single steel angle, with the vertical leg behind the brick and the horizontal leg under it.

That split is why the angle sizes in the code look modest for such a wide opening. The angle is not holding up the roof. It is holding up masonry, and the code tables assume some of that masonry arches over the opening on its own.

When the wall is solid masonry, or when the steel has to carry part of the roof or a floor, the job changes and the tables below may not apply.

Single garage doors: steel angle sizes

Table 9.20.5.2.-B lists the minimum angle for each veneer type. Here are the rows that cover common single door widths. Spans are maximum allowable spans in metres.

Source: 2024 Ontario Building Code, Division B, Table 9.20.5.2.-B.

Applied to typical openings:

• 8 ft door (about 2.44 m). An L89 × 89 × 6.4 just covers it in 70 mm or 90 mm brick, but only if the masonry opening really is under 2.47 m. Masonry openings are often a little wider than the door itself, so measure the brick opening, not the door. In stone, go to the L102 × 89 × 6.4 or heavier.
• 9 ft door (about 2.74 m). The L102 × 89 × 6.4 is too short in 90 mm brick (2.66 m). The L127 × 89 × 7.9 covers it in all three veneer types.
• 10 ft door (about 3.05 m). The L127 × 89 × 7.9 still works in brick (3.31 m) and just reaches 3.08 m in stone, again only if the opening is no wider than that.

The listed angle is a minimum. A heavier angle is always acceptable, and many builders standardise on one size for all their single garage doors so the bundle on site is simple.

Double garage doors: when an angle is not enough

A 16 ft door is about 4.88 m wide, and an 18 ft door about 5.49 m. The largest angle in Table 9.20.5.2.-B, an L178 × 102 × 13, is rated for 4.87 m in 70 mm brick, 4.59 m in 90 mm brick and 4.25 m in 100 mm stone. So in standard 90 mm brick or stone, no angle in the table spans a 16 ft door.

For these openings the code offers Table 9.20.5.2.-C, which lists wide-flange beams that support masonry veneer and a wood stud wall above:

Source: 2024 Ontario Building Code, Division B, Table 9.20.5.2.-C. Spans in metres.

Read against a 16 ft door, a W200 × 27 reaches 5.08 m in 90 mm brick, and stone needs at least a W200 × 31. An 18 ft door in 90 mm brick sits right at the limit of the heaviest beam listed, so in practice it is designed by an engineer.

The table comes with conditions that change how the opening is built:

• A steel column at each end. Sentence 9.20.5.2.(6) requires the beam to be supported by a steel column at each end, not just bearing on the brick returns. Those columns need their own footings.
• A welded plate for the veneer. The beam needs a plate at least 6 mm thick welded to the flange to carry the masonry.
• Limited loads. The spans assume the beam carries the veneer, a wood stud wall and a specified roof live load of no more than 2.3 kN/m. If the beam carries floor loads or larger roof loads, the code sends you to the steel beam requirements in Article 9.23.4.3. instead.

If the W-shape names are unfamiliar, our steel beam span tables guide explains how they are read.

Bearing, length and the brick beside the door

For angle lintels sized from Tables 9.20.5.2.-A and -B, Sentence 9.20.5.2.(3.1) requires even and level bearing of at least 150 mm at each end, on masonry, concrete or steel. So a lintel is at least 300 mm longer than the opening. A 2.7 m masonry opening needs an angle at least 3.0 m long.

Garage fronts often have narrow brick piers beside the door, and sometimes a door sits close to the corner of the house. Check that there is enough solid masonry at each end to give full bearing. If not, the detail needs a designer. Our article on steel lintel bearing length covers bearing in more depth.

The code's design notes for these tables also assume arch action: brick within a 45 degree line from each edge of the opening is not counted as load on the lintel, because it arches over. The same notes, for the beam tables that carry roofs and floors, point out that windows in the wall above nullify arch action. A garage with a window, vent or a short band of brick between the door and the eaves may not behave the way the table assumes. That is a judgement for your designer, not the installer.

When a garage door lintel should be engineered

Use an engineer, not the tables, when:

• There is a room over the garage. A bonus room or bedroom puts floor loads on the opening, and the steel often ends up carrying more than veneer.
• A girder truss or beam lands near the opening. Concentrated loads are outside the tables.
• The opening is wider than the table covers for your veneer, or you want a slimmer member than the table gives.
• The wall is solid masonry rather than veneer over framing.
• You are widening an existing opening, for example converting two single doors into one double door. That changes the load path in the wall and needs a permit.

An engineered garage lintel might be a heavier W beam, a beam with a plate welded to the bottom flange to carry the brick, or a built-up section. These are fabricated to the engineer's drawings, with the plate, bearing plates and any holes for fastening to the framing done in the shop. For more on wider openings in exterior walls, see steel beams for home additions and exterior wall openings.

Corrosion, sagging and replacement

Sentence 9.20.5.2.(4) requires steel angle lintels supporting masonry to be prime painted or otherwise protected from corrosion. Garage lintels sit low, catch splash from the driveway and see road salt carried in on vehicles, so they rust faster than lintels higher up the wall. Galvanizing, or a primer and topcoat system kept in good repair, is common for these openings.

Signs a garage lintel needs attention:

• A visible sag in the brick line over the door, or a gap opening between the brick and the door frame
• Stair-step cracks running up from the corners of the opening
• Rust scale pushing the brick up or out at the ends of the angle
• Mortar dropping from the course just above the steel

Replacing a lintel in an existing brick wall means supporting the masonry first, then removing and rebuilding brick above the opening. It is structural work and is not a DIY job. Our guide to replacing a rusted steel lintel explains how it is done and who does what.

Ordering a garage door lintel

To quote a garage lintel accurately we need:

• The masonry opening width, not just the door size
• The veneer type and thickness (70 mm or 90 mm brick, or stone)
• The angle size or beam size from your drawings, if you have them
• The finish you need, so we can confirm the options for your job
• Any engineered details, such as welded plates, end plates or holes

We cut angles to length and fabricate W beam lintels with welded plates to your drawings, with CWB certified shop welding. Send us your opening sizes or drawings for a quote, or see our steel products for the lintels, beams, posts and plates we supply.