Two of the most structurally critical elements in any masonry or concrete construction project are lintels and reinforced concrete. Both involve spanning loads over openings or distributing forces through structural members, and both require the right specification, the right materials, and a clear understanding of what they’re being asked to do.
At Seymour Building Supplies in Gladesville, the team has been helping Sydney’s tradies, builders and DIY customers with exactly these kinds of questions since 1985. Here’s a practical guide to both.
Lintels for Brickwork: What They Are and Why They Matter
A lintel is a horizontal structural member placed across the top of an opening in a masonry wall, such as a door, window or garage opening. Its function is to span the opening and carry the load of the brickwork, blockwork or structure above it, transferring that load to the masonry on either side.
Without a correctly specified and installed lintel, the masonry above an opening would have no structural support. The result would be cracking, movement and potentially structural failure of the wall above the opening. This makes lintel specification one of the most important structural decisions in any masonry project.
Types of Lintels Available at Seymour Building Supplies
Steel angle lintels are the most widely used type of lintel in Australian residential brickwork. A steel angle lintel is an L-shaped steel section that bears on the brickwork either side of the opening. The horizontal leg carries a single leaf of brickwork (in brick veneer, the external brick skin), while the vertical leg stands up behind the bricks and gives the lintel its stiffness over the span. Galvanised steel angle lintels are standard for external walls where moisture and corrosion are a concern.
Seymour Building Supplies stocks galvanised lintel bars in 100 x 100 x 6mm, 100 x 150 x 6mm and 100 x 150 x 10mm profiles, along with render bar lintels and flat bars. The team can advise on the correct size for your opening width and the load conditions involved.
T-bar lintels are another common configuration. A T-bar has a horizontal flange with a vertical web rising from its centre, so it can carry brickwork on both sides of the web. T-bars are typically used for thicker masonry walls and heavier loads where a single angle isn’t enough. Seymour Building Supplies stocks 200 x 200mm T-beams in lengths from 900mm up to 6300mm.
Precast concrete lintels are often used in block or concrete masonry walls, or where fire resistance, thermal performance or load capacity requirements make steel a less suitable option. Seymour Building Supplies stocks precast concrete lintels in 110 x 80mm and 170 x 110mm sections, with other sizes available on request. Concrete lintels can also be formed and poured on site.
How to Specify the Right Lintel
The specification of a lintel depends on three key factors.
Span refers to the width of the opening being bridged. As a general rule, a lintel should extend a minimum of 150mm past each side of the opening to provide adequate bearing on the masonry. For wider openings, this bearing length may need to be increased.
Load refers to what the lintel is being asked to support. The height of brickwork above the opening, the presence of any floor or roof structure above, and the wall’s position within the building all influence the structural load the lintel must carry. For structurally critical applications, a structural engineer should specify the lintel size and configuration.
Material refers to the choice between steel, galvanised steel, stainless steel or concrete, depending on the environment (coastal locations require galvanised or stainless steel for corrosion resistance), fire resistance requirements and budget.
The team at Seymour Building Supplies can help you identify the right standard lintel for common residential applications. For complex or high-load situations, a structural engineer’s specification is recommended. You can view the full range on our Lintels & T Bars page.
Reinforced Concrete Materials: Understanding What You Need
Concrete is one of the most widely used construction materials in the world, and for good reason. It is strong in compression, durable, fire-resistant and relatively affordable. But concrete has a significant limitation: it is weak in tension. When a concrete element is subjected to bending, the side in tension is prone to cracking and failure unless something is done to address this weakness.
Reinforced concrete material addresses this by embedding steel reinforcement, typically in the form of ribbed bars (rebar) or mesh, within the concrete before pouring. The steel carries the tensile forces while the concrete carries the compressive forces, producing a composite structural material that is strong in both compression and tension and capable of spanning, cantilevering and carrying loads that plain concrete cannot.
Steel Reinforcement
Deformed reinforcing bar (rebar) is the most commonly used reinforcement product in Australian construction. The deformations on the bar surface provide mechanical bond between the bar and the surrounding concrete, ensuring the two materials act together structurally rather than slipping relative to each other.
Rebar is available in sizes ranging from N10 (10mm diameter) through to N40 for heavy structural applications. The most common sizes in residential construction are N12 and N16, used in footings, slabs, retaining walls and columns.
Seymour Building Supplies stocks deformed reinforcing bar in the standard sizes required for residential and light commercial applications, with the team available to help calculate the quantities and layout required for your specific project.
Reinforcing mesh is a prefabricated sheet of steel bars welded together at set spacings, typically used in slabs and structural wall panels where a uniform reinforcement pattern is required over a large area. Mesh is faster to install than individually tied rebar and is appropriate for many standard slab and pavement applications.
Bar chairs and spacers are the plastic or steel supports used to hold the reinforcement at the correct position within the slab or element, ensuring the concrete cover specified in the design is achieved. Achieving adequate cover is critical for both structural integrity and long-term corrosion protection of the steel.
Tie wire is used to secure the intersecting bars or mesh sheets together at their junctions, preventing movement during the concrete pour.
Cement and Concrete Mix
Seymour Building Supplies stocks a comprehensive range of cement and dry concrete products from leading brands including Boral, Sika, Mapei and Drizoro. This includes general purpose cement for site-batched concrete, pre-blended post mixes for small pours and fence posts, rapid-setting products where early strength gain is required, and specialised repair mortars and grouts for structural repair and patching applications. See the full range on our Cements & Dry Mixes page.
Get the Right Lintels and Reinforcement for Your Project
To discuss your lintel or reinforced concrete material requirements and get the right products for your project, visit our building supplies page or call the team on (02) 9816 5999. You’ll find us at 327 Victoria Rd, Gladesville.
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