When Is a Steel Lintel Required? Ontario Code Basics

A steel lintel is required wherever masonry spans over an opening. The 2024 Ontario Building Code says masonry over openings must be supported by steel lintels, reinforced concrete lintels or masonry arches (Sentence 9.20.5.2.(1)), and since arches and concrete lintels are rare in new houses, steel angles do almost all of that work. That includes brick and stone veneer over the windows and doors of an ordinary wood-frame house.

Where there's no masonry above the opening, a steel lintel usually isn't required. Wood-frame walls use wood lintels (often called headers), and concrete and ICF walls use reinforced concrete. Here's how to tell which applies.

The rule: masonry has to sit on masonry, concrete or steel

Two articles in Part 9 of the 2024 OBC (O. Reg. 163/24) set this up:

• Sentence 9.20.5.1.(1): all masonry shall be supported on masonry, concrete or steel (with a narrow exception for veneer on permanent wood foundations).
• Sentence 9.20.5.2.(1): masonry over openings shall be supported by steel or reinforced concrete lintels, or masonry arches, designed to support the imposed loads.

So the question "do I need a steel lintel?" comes down to: is there brick, block or stone above this opening? If yes, something non-combustible and structural has to carry it, and in most houses that's a steel angle sized from the code tables.

The code then says which tables to use:

Source: 2024 Ontario Building Code, Division B. Angle sizes and spans for each table are in our steel lintel sizes guide.

Steel lintels in wood framing and timber frame

This is where most of the confusion comes from. A typical Ontario house has a wood-frame wall with brick veneer on the outside. The two layers are separate structures, and each needs its own support over a window or door:

• The wood wall carries the floors and roof. Over an opening in a loadbearing wood wall, Sentence 9.23.12.2.(1) requires a lintel designed to carry the loads to the studs beside the opening, and Article 9.23.12.3. points to the wood lintel span tables. That's a wood member (or an engineered one if the tables don't reach).
• The brick veneer carries only its own weight, but that weight still has to cross the opening. Because masonry must be supported on masonry, concrete or steel, the veneer gets a steel angle lintel sitting in the brick, with one leg under the brick and one leg standing up behind it.

So the answer to "steel lintel wood framing" is: the wood wall gets a wood lintel, the brick gets a steel angle. If the house has siding or stucco instead of veneer, there's usually no steel lintel at all.

Timber frame and post-and-beam homes follow the same logic. The timber structure carries the loads, but any masonry veneer or stone facing that crosses an opening still needs steel or concrete under it.

When the wood wall needs steel. Over a wide opening with veneer and a stud wall above, such as a patio door or garage door, an angle may not be enough. Table 9.20.5.2.-C lets a steel wide-flange beam carry both the veneer and the wood stud wall, with a steel column at each end and a plate at least 6 mm thick welded to the flange to support the brick. Where a lintel also carries floor loads or larger roof loads, the code points to its steel beam tables or to an engineered design. Our post on steel lintel vs beam explains where one ends and the other begins.

When a steel lintel is not the answer

Some openings don't get a steel lintel at all:

• Wood-frame walls with siding or stucco. Wood lintels under Subsection 9.23.12. In non-loadbearing walls, openings are framed with 38 mm material (Article 9.23.12.1.).
• ICF walls. In loadbearing flat ICF walls, lintels are required over all openings wider than 900 mm, and they are reinforced concrete lintels built to the ICF lintel span tables (Article 9.20.17.4.). Openings over 1,200 mm also need 10M stirrups.
• Poured concrete walls. Openings in cast-in-place concrete walls are spanned by the concrete itself, usually with reinforcing bars over the opening as the designer details.
• Masonry arches. The code still allows a properly built masonry arch, though they're mostly seen in heritage work.

Concrete block foundation walls are a middle case: a new basement window in block usually gets a steel lintel or a reinforced bond beam, depending on the design. See our post on steel lintels for basement egress windows.

Steel lintel requirements once one is required

If your opening needs a steel lintel, the code attaches a few conditions:

• Size from the tables or by design. Angles follow Table 9.20.5.2.-A or -B for the span and wall type. Openings beyond the tables, or with concentrated loads above, are engineered.
• Bearing. At least 150 mm at each end, even and level, on masonry, concrete or steel (Sentence 9.20.5.2.(3.1)). Our post on steel lintel bearing length covers the details.
• Corrosion protection. Steel angle lintels supporting masonry must be prime painted or otherwise protected from corrosion (Sentence 9.20.5.2.(4)).
• Flashing and weeps. Openings in exterior masonry walls generally need flashing over the head unless sheltered by the roof overhang, and veneer cavities above flashed lintels need weep holes, as set out in the code's masonry flashing rules.
• Bolting in solid masonry. In the walls Table 9.20.5.2.-A covers, interior and exterior angles are bolted together when the clear span is over 1,800 mm (Note 5 to the table).

Renovations that trigger a steel lintel

You'll typically need a new steel lintel when you:

• Cut a new window or door into a brick or stone wall.
• Widen an existing opening, because the old lintel is now too short or too light.
• Replace a rusted lintel that has started to crack or push out the brick. See replacing a rusted steel lintel.
• Add a basement egress window in a block foundation wall.
• Enlarge a garage door opening in a veneer wall.

All of these are structural alterations. They need a qualified designer or engineer to size the lintel and detail the shoring, and in GTA municipalities they generally need a building permit. Our article on installing a steel lintel in an existing brick wall explains the process step by step.

Getting your lintel made

We fabricate steel angle lintels and beam lintels cut to length and punched, drilled or welded to your detail, with CWB certified shop welding, and deliver across the GTA and Ontario. Engineering services are available for projects that need them. Send your opening sizes or drawings for a quote, or see our steel products.