Over a window or patio door in a brick or stone veneer house, the steel lintel is usually an angle that carries only the veneer, and its size comes from the opening width and the type of veneer. Under the 2024 Ontario Building Code, Table 9.20.5.2.-B sets the minimum angle for each span, and the lintel needs at least 150 mm of bearing at each end. Very wide patio doors can go beyond the largest angle and need a W-beam lintel with a plate welded on. The cost is set by the section, the length, any fabrication, the finish and the installation.
This guide focuses on what's specific to windows and patio doors: which member goes where, how the head of the opening is flashed so the lintel lasts, and what moves the price. For the full code tables, see our article on steel lintel sizes under the Ontario Building Code.
What sits above a window in a brick house
Most newer Ontario houses are wood-framed with a single layer of brick or stone veneer outside. That gives every window and door two separate members overhead:
- A steel angle lintel in the veneer, carrying the brick or stone above the opening.
- A header in the wood wall behind it, carrying the floor, roof or wall loads.
The steel angle doesn't hold up the house. That's why window lintels can be small, and why "steel beam over window" is a different question when the wall is load-bearing and the opening is new or wider. Our guide to steel lintel vs beam explains the difference, and when a steel lintel is required covers which openings need one.
Sizing angle lintels for windows and patio doors
For angles carrying masonry veneer, Table 9.20.5.2.-B gives a maximum span for each angle and veneer type. A few examples for 90 mm brick:
| Typical opening | Example width | Smallest listed angle (90 mm brick) | Minimum lintel length |
|---|---|---|---|
| Standard window | 1.8 m | L89 x 89 x 6.4 (to 2.47 m) | 2.1 m |
| Patio door or wide window | 2.6 m | L102 x 89 x 6.4 (to 2.66 m) | 2.9 m |
| Wide patio or picture window | 3.2 m | L127 x 89 x 7.9 (to 3.31 m) | 3.5 m |
| Very wide slider or folding door | 4.5 m | L178 x 102 x 13 (to 4.59 m) | 4.8 m |
Source: 2024 Ontario Building Code, Division B, Table 9.20.5.2.-B. Angle sizes are vertical leg x horizontal leg x thickness in millimetres. Stone veneer and 70 mm brick have their own columns, so check the full table for your wall.
Three rules apply to every angle lintel sized from the table:
- Bearing. At least 150 mm at each end, even and level, on masonry, concrete or steel. So the lintel is at least 300 mm longer than the opening. See steel lintel bearing length.
- Corrosion protection. Steel angle lintels supporting masonry must be prime painted or otherwise protected.
- Orientation. On an unequal angle, the longer leg stands vertical behind the veneer and the shorter leg sits under the brick.
Angles listed in the table are minimums. A heavier angle is acceptable; a lighter one isn't. If your opening is wider than the table covers, or the wall isn't the type the table describes, the lintel has to be designed.
W-beam lintels over wide patio doors
When an opening is too wide for an angle, Table 9.20.5.2.-C lists wide-flange beams that carry masonry veneer plus a wood stud wall, from W150x22 to W200x36. In 90 mm brick, those beams range from 4.09 m to 5.49 m of span. The table comes with conditions:
- The beam carries the veneer, a wood stud wall and a specified roof live load of no more than 2.3 kN/m.
- It is supported by a steel column at each end.
- A plate at least 6 mm thick is welded to the flange to carry the veneer.
If the beam also carries floor loads or heavier roof loads, the table doesn't apply and the beam is sized under the code's steel beam requirements or by an engineer. Wide sliders and folding doors in rear walls often fall into this group, which we cover in steel beams for home additions and exterior wall openings.
The window head detail: keeping the lintel dry
A lintel that stays wet will rust, and a rusting lintel pushes the brick above it out of line. Most of what makes a window or door head last is in the detail around the steel, not the steel itself. The 2024 Ontario Building Code requires:
- Flashing over the head of window and door openings in masonry walls (Article 9.20.13.3), unless the distance from the top of the frame to the bottom of the eave is no more than a quarter of the eave overhang.
- Flashing that extends from the front edge of the masonry up behind the lintel (Article 9.20.13.4).
- Weep holes at no more than 800 mm apart at the bottom of the air space, including the space above lintels over openings that must be flashed (Article 9.20.13.8).
- Watertight joints in the flashing (Article 9.20.13.7).
- Sealant at the junction of window and door frames with masonry (Article 9.20.13.11), and window installation to CSA A440.4 (Article 9.7.6.1).
Good practice adds a few things the code doesn't spell out in these articles:
- End dams at each end of the flashing so water exits through the weeps instead of running into the wall at the jambs.
- A gap between the lintel and the window frame, so the lintel can deflect slightly without bearing on the window. The window should be supported on its own framing, not by the steel.
- A coating that suits the exposure. Primer meets the minimum; some builders and designers specify more durable protection.
Your designer, window installer and mason coordinate this detail. If you are replacing a lintel in an existing wall, the same rules apply, and our guide to installing a steel lintel in an existing brick wall walks through the process.
What drives the cost of a window or door lintel
The lintel is usually one of the smaller costs in a window or door project. What moves its price:
- Section and length. Steel is priced by weight, so a longer opening and a heavier angle cost more.
- Type. A plain angle cut to length is the simplest. A W-beam lintel with a welded plate, plus posts at each end, is a fabricated assembly with much more work in it.
- Fabrication. Holes, welded plates, notches or cut ends.
- Finish. Primer, paint or other protection.
- Quantity. Ordering every lintel for a house together, grouped by size, is more efficient than one at a time.
- Installation. On new construction the mason sets the lintel as the wall goes up. On an existing wall, shoring, brick removal, rebuilding and making good inside are where most of the cost is.
Our guide to steel lintel cost in Ontario goes through each of these in detail.
Ordering lintels for windows and doors
Send a list of openings with the width of each, the veneer type and thickness, and whether any opening is in a load-bearing wall or getting wider. If the lintels have already been sized by your designer, send the sizes and lengths. Mark any W-beam lintels with their plate and post details.
We supply steel angle lintels for masonry openings, cut to length and punched or welded as needed, and wide-flange beams fabricated with plates and connections, with CWB certified shop welding and delivery across the GTA and Ontario. Send your opening list or drawings for a quote, or browse our steel products.
Frequently asked questions
What size steel lintel do I need over a window?
In a brick veneer house sized under Part 9 of the Ontario Building Code, the angle comes from Table 9.20.5.2.-B based on the opening width and the veneer. For example, an L89 x 89 x 6.4 is listed for spans up to 2.47 m in 90 mm brick. The lintel is at least 300 mm longer than the opening, for 150 mm of bearing at each end.
Do patio doors need a steel beam instead of an angle?
A standard patio door in brick veneer is usually within the range of a steel angle. Very wide openings can exceed the largest angle in the table, and then a W-beam lintel with a plate welded to it carries the veneer. If the opening is in a load-bearing wall, the structural header or beam is designed separately.
Does a steel lintel over a window need flashing?
Generally yes. The 2024 Ontario Building Code requires flashing over the heads of window and door openings in masonry walls, running from the front edge of the masonry up behind the lintel, unless the opening sits close enough under a roof overhang. Weep holes at no more than 800 mm apart drain the space above the lintel.
How much does a steel lintel over a window cost?
The price depends on the angle or beam size, the length, any fabrication such as welded plates, the finish and whether installation is included. A small angle over a single window is a modest item; a W-beam lintel over a wide patio door with plates and posts costs much more. Send the opening sizes for a quote.
