We’ll cut straight to it. A lintel is a fancy term for additional supporting structures found above openings like doorways and windows. Often decorative in their designs, these common load-bearing structures are used to support a building’s architecture by transferring weight from the high wall to the sides.
Supplying steel lintels and T-Bars to the market since 2009, we’re well versed in this particular type of steel. Lighter and easier to handle on-site than precast concrete lintels, steel lintels offer more versatility than some other types of lintels and are much stronger than timber. If you’re planning to add new openings, you’ll need to know a thing or two about lintel construction before you start knocking out walls or building your home from the ground up.
Reinforce with confidence with the Steel Builders guide to lintels in construction.
Technically referred to as flexural members, lintels are horizontal beams used to support the wall above an opening. Commonly found above doorways and windows, lintels are made from a range of materials such as timber, stone, brick, concrete, and of course, steel.
Although they are often avoided in modern structures due to their susceptibility to fire, decay and termites, wooden lintels have been used for centuries. Still popular today, especially in areas where timber is widely available, these lintels consist of a single piece of wood for small openings or multiple pieces of wood held together by bolts. Unfortunately, wooden lintels are comparatively weak due to the anisotropic properties of timber.
Stone is another material that has made its mark on architecture since early civilisation. And just like the material they’re made from, stone lintels are exactly what they sound like, a slab of stone used to support an opening. While it may seem like a strong choice for load-bearing, stone actually has a relatively low tensile strength compared to steel, limiting its application to openings of only a few metres in length.
For example, a stone lintel of longer than 1 metre is likely to break in two without relieving arches. And that’s before we even mention how difficult it is to obtain slabs of stone that are of sufficient size. Oh, and did we mention they’re ridiculously heavy and expensive to transport?
Closely related to its stone brethren, brick lintels are constructed using hard, well burnt first-class brick. However, much like stone, brick lintels are restricted to small openings of less than 1 metre in length. Bricks with frogs filed with mortar are often used for added shear resistance.
There are also reinforced brick lintels arranged in parallel rows with enough space in between for steel bars or rods and cement for added reinforcement. Although stronger than standard brick lintels, they are not recommended for high humidity or rainfall areas, as increased moisture may cause the steel to rust over time.
Concrete is one of the most used materials in construction, thanks to its compression strength. Poured out and moulded to its necessary dimensions, plain concrete beams are used to support openings. However, due to its relatively weak tensile strength, concrete lintels are limited to smaller spaces of only a few metres in length.
An easy way to increase this is by using reinforced concrete lintels. Durable, strong, economical, and easy to construct, RCC lintels are reinforced with steel bars, precast for efficient installation on site.
Now we’ve come to the MVP of the lintel world. Consisting of rolled steel joists that are embedded in concrete, steel angles, or channel sections within the concrete, steel lintels offer the necessary properties to support heavy loads across wide openings. Impervious to rust, erosion, and distortion thanks to its isotropic properties, steel lintels are a practical and less labour-intensive option for superimposed loads.
What makes steel so versatile is the selection of treatments for different environments and scenarios. Steel treatments are added to provide ctive or inhibitive corrosion resistance. These include untreated, Zinc phosphate priming, Zinc spray metallising, chemical coating and hot dipping (galvanised steel).
Different Types of Steel Lintels
Loose angle lintels are used for brick veneer and cavity wall constructions where the lintel is laid in the wall, spanning the entire opening.
Combination Lintels are used in solid masonry walls when a single lintel isn’t enough to support the weight. For example, multiple Angle Lintels are placed back to back in masonry walls. In walls with much larger superimposed loads, or walls where the opening exceeds 2.4m in length, you may need to use Steel Beam/Plate Lintels.
Shelf angles are used in panel wall systems to support the exterior wythe (a continuous vertical section) of brickwork.
Using Lintels in Construction
Whenever there are openings in masonry walls, you’re going to want to do something to control moisture levels. Ensure that any water present inside the wall can flow outside.
Flashing and Weepholes
Even with galvanised steel lintels, flashing is necessary for lintels inside cavity and veneer walls. Flashing should be installed between the steel and the exterior masonry facing material to collect and divert moisture to the outside through weep holes (gaps left between brickwork for ventilation and drainage).
Movement and Expansion
Steel might not be as temperamental as timber. However, due to the diversity of movement characteristics between different materials, you’ll need to consider expansion, particularly where several different materials come together.
Expansion joints, for example, are used in brick masonry to prevent cracking caused by the expansion and movement of construction materials. Expansion joints come in two varieties - vertical and horizontal. Ironically, vertical joints permit horizontal movement of the brick masonry, while horizontal joints allow for vertical movement.
Everything You Need To Know About Lintels
And there you have it. Everything you need to know about lintels from a premier steel fabricator: check out Steel Builders today for more information.