You may think this is a silly question, but dig a little deeper and we can examine more than the obvious material differences. There are many reasons to specify a steel lintel but here we can look at why they may be favoured by the construction industry, and what use concrete lintels have in modern housebuilding.
Strength to weight ratio
The comparative weight of steel to concrete makes it a very viable product for modern construction.
One of the biggest advantages that steel lintels have over prestressed concrete lintels is their strength to weight ratio. Steel offers much better load bearing capabilities over concrete when looking at the comparative weight. This generally makes using steel a lot easier on site. Below is a table highlighting the difference between a steel lintel and a comparable concrete lintel.
| Length | Concrete | Steel | ||
|---|---|---|---|---|
| 140x100 Std | 90mm HD | |||
| SWL (kN) | Weight (kg) | SWL (kN) | Weight (kg) | |
| 1200mm | 31.56 | 39.60 | 42.00 | 9.96 |
| 3000mm | 10.20 | 99.00 | 41.00 | 49.50 |
Concrete has good compressive strength but relatively poor tensile strength, which is why high tensile prestressed steel wires are included in the manufacturing of concrete lintels, and generally used at the bottom of the lintel.
Steel lintels have good compressive and tensile strength, which is why it lends itself to modern construction. The various types and grades also mean that steel can be manipulated for certain applications, making it very versatile as a structural product.
Fire rating
Concrete is generally fire resistant, and in some cases can reduce the spread of fire. Steel, when heated, can lose its integrity and therefore its load bearing capability, so when specifying lintels some consideration ought to be made to fire resistance; especially in areas where fire is more of a potential hazard.
Thermal bridging
The thermal properties, resistance to fire and corrosion and cost still ensure that concrete lintels are an attractive alternative to steel lintels.
Concrete lintels can reduce the cold bridge in properties because of the nature of the product. It is a good insulator and therefore acts as better insulation than steel. Building designs obviously include other methods of insulation to combat cold-bridging, but in some circumstances, concrete lintels may be looked at as a viable option because of this factor.
Corrosion
Steel, when subjected to moisture, can corrode, and other chemical factors such as salt in sea air can also corrode types of steel. There are many types of steel and different grades of steel which react to potentially corrosive materials differently, but stainless steel is an option to combat corrosion when looking at lintels. Prestressed concrete lintels are less susceptible to moisture and chemical corrosion, which is why they are often specified in areas where this may be a factor.
Cost
Concrete is generally a great deal cheaper than steel, and as with everything in life, the cost is often a big if not defining factor in the selecting and buying process. The cost of installation will be a factor, but when it comes down to the product, on a like for like basis, concrete will cost less.
For more information on steel and concrete lintels contact our technical team, and you can look at our blog post on why you might want to specify concrete lintels and don’t forget to sign up for our monthly digest. It is free, which is even cheaper than concrete.
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