Precast concrete lintels | 9 Different Types of Lintels | Precast Concrete Advantages & Disadvantages
Precast concrete lintels | 9 Different Types of Lintels | Precast Concrete Advantages & Disadvantages
What are Lintels?
A lintel is an element of construction used to span or bridge a gap between two structural supports (commonly vertical columns).
A lintel can be made of many things, such as stone, brick, wood or steel. In carpentry a one-piece lintel is called a saddle.
The precast concrete lintels are formed through the use of machines and hand work and are usually made from reinforced cast concrete that has either been shotcrete finished or sprayed with coloured cement paint, which makes a very strong protection against corrosion.
The lintels are completed based on specifications provided by engineers who have been trained to design concrete lintels.
On a construction site, the lintels are usually installed by a crane or through the use of advanced cranes with special machinery.
When planning to construct a home, one must decide which type of concrete lintel will be needed.
Lintels can vary in their qualities according to the intended use.
For example, depending on the location and environment they are going to be placed in, they can be formed from either reinforced concrete or precast concrete.
A lintel does not need to be made from concrete or precast concrete. In some cases, a wood lintel can also be used instead of concrete lintels.
Precast Concrete Lintels Width
Very often, the width of the lintel depends on the structure where it will be installed. For example, a beam that is several parts wide would require a bigger lintel compared to beams that are in one piece.
Precast Concrete Lintels Thickness
The thickness of the lintel also differs depending on what they are going to be used for and their installation requirements.
For example, when a lintel is going to be installed as a beam, it must be thicker compared to one that is going to be installed as a lintel that spans from one support to another.
The thickness of the lintel also varies depending on the type of construction support on which it will be laying on.
For example, if the lintel is going to go over a beam at a 90-degree angle (90°), then the lintel must be much thicker compared to an angle of 30 degrees or 45 degrees.
The type of lintel also depends on what kind of conditions the lintel will be exposed to during its lifespan.
For example, in an area with high humidity, the lintel must be thicker compared to low humidity areas.
Similarly, the installation location or support determines the proper thickness of the lintel. For example, a lintel that is going to go over a beam must always be thicker compared to one that is going to be installed under a beam.
Lintels serve as beams, supporting the weight of the wall and other loads over an entrance and transferring these loads to the nearby masonry.
The most common types of lintels for concrete masonry construction are those made of precast reinforced concrete or reinforced concrete masonry units because of its rigidity, strength, durability, fire resistance, and aesthetically.
Precast Concrete Lintels System
The precast concrete lintel system is a unique and versatile building assembly system that is easily constructed with a minimum of material and labor.
It employs prefabricated ready-mix concrete blocks in the form of lintels, wedge beams, and deck slabs.
The pattern of the precast elements is determined by the structural requirements, which can be as simple as a beam resting on top of other beams or as complex as an entire structural system spanning between support columns.
Precast Concrete Advantages
- Higher load capacities than cast-in-place concrete.
- Precast concrete lintels can be used to span up to 40m between columns, without intermediate beams.
- Can be installed off-site and then hoisted into place, avoiding long-term site disruption.
- Facilitates onsite construction, as there is no need for formwork or falsework.
- High durability of precast concrete allows for reduced maintenance costs.
- Low embodied energy in comparison to other building materials.
- Safe, reliable, and cost-effective solutions to structural problems and a wide range of applications.
- Can be produced in low quantities, reducing waste – e.g. if only one beam is needed, it can be manufactured off-site with little extra cost (and resulting in little or no waste).
Precast Concrete Disadvantages
- Longer design, manufacture, and erection times.
- More expensive than other lightweight materials, such as wood.
- High capital costs to install a precast concrete lintel system.
- Relatively high installation cost since they are custom manufactured for the project and on-site handling is required.
- Inconvenient for long spans requiring lifting (greater than 25m).
- Limitations of shape or form due to the construction requirement of the specific span or bridging gap it is being used to support.
Precast Concrete FAQs
1. What are the advantages of using precast concrete lintels as opposed to other building materials?
a) Precast concrete lintels can be used to span up to 40m between columns, without intermediate beams.
b) Precast concrete can be installed off-site and then hoisted into place, avoiding long-term site disruption.
c) Precast concrete is a versatile building assembly system that is easy to construct with a minimum of material and labor.
d) Precast concrete is easily installed in factories or on a construction site, without extra material costs.
e) Precast concrete lintels are manufactured from high-grade cast concrete, with high durability properties and guarantees.
f) Precast concrete lintels are produced in low quantities, reducing waste – e.g. if only one beam is needed, it can be manufactured off-site with little extra cost (and resulting in little or no waste).
2. What are the advantages of using precast concrete beams as opposed to other building materials?
a) Precast concrete beams can weigh up to one-third less than conventional cast-in-place concrete beams.
b) Precast concrete beams can be used in applications where tensile and compressive forces act in the same direction.
3. What are the advantages of using precast concrete lintels as opposed to other building materials?
a) Precast concrete lintels can be used to span up to 40m between columns, without intermediate beams.
b) Precast concrete can be installed off-site and then hoisted into place, avoiding long-term site disruption.
4. What is the precast concrete lintels sizes?
a) Precast concrete lintels sizes – The typical lintel span is between 0.8-7 metres.
b) Precast concrete lintels sizes – Lintels in the form of beams and deck slabs can vary from 1/4″ to 3″.
5. What is the precast concrete lintels weights?
Precast concrete beams and lintels can weigh up to one third less than traditional cast-in-place concrete beams.
6. What is the precast concrete compressive strengths?
Concrete compressive strengths for precast lintels typically range from 2500 to 3500 psi. Reinforcement is specifically engineered with a yield strength of 60,000 psi.
Different Types of Lintels
There are different types of Lintels used in construction. The different types include:
A – Reinforced Concrete Lintels
The reinforced concrete lintel is an essential part of building construction. They are strong, durable and can be formed in various sizes and shapes to meet the requirements of the project.
They are also easy to handle as they have less weight compared to other types of concrete.
B – Precast Concrete Lintels
Precast concrete lintels have a great impact on building design and the construction process, though they are often underestimated.
They are stronger, more durable, and are not costly as reinforced concrete. They can be used even in tight spaces.
C – Wood Lintels
Wood lintels are one of the most common types of lintels found in the construction industry around the world.
They are durable and easy to install but they have a limited lifespan due to their weakness when exposed to high moisture conditions.
Timber is one of the most common types of lintel used in construction. It is easy to install and repair and is often used in places where a traditional beam would be too heavy or expensive to use.
D – Steel Lintels
Steel lintels are one of the toughest and most durable types of lintel in construction. They are perfect for bracing walls, supporting beams, and spanning space between supports.
However, they can be very costly to buy, construct and install.
E – Lintels used on small projects
For small projects, such as bathroom remodeling or repairing your porch roof, you can use lintels that are easily available in the market which vary in size and shape.
F – Brick Lintels
Brick lintels are similar to concrete lintels. They provide support over beams and can be used for either interior or exterior purposes. However, they are not as strong as reinforced concrete lintels.
G – Stone Lintels
Stone lintels are used for supporting beams, walls, and other structures. They are strong and easily available in the market with a wide variety of shapes and sizes.
These lintels can be installed over wooden beams or concrete beams.
H – Steel Lath Lintels
Steel lath lintels are used for installing above windows and doors to act as decorative elements for the rooms.
They can be manufactured at different thicknesses in order to accommodate different window locations respectively.
I- Composite Structural lintel
This type of lintel is commonly made up of a combination of brick and steel. They are available in different types such as brick/shotcrete, stone/steel bar, and concrete/steel.
This type of lintel is similar to the composite structural lintels but they are used for installing above windows and doors as well as acting as decorative elements for the rooms.
The advantage of this type of lintel is that it does not require any special tools for installation or finishing.
Lintels FAQs
1. What are the different types of lintels used in construction?
- a) Reinforced concrete lintels
Reinforced concrete lintels are one of the most common types of lintels found in the construction industry around the world.
They are durable and easy to install but they have a limited lifespan due to their weakness when exposed to high moisture conditions.
- b) Precast concrete lintels
Precast concrete lintels have a great impact on building design and the construction process, though they are often underestimated.
They are stronger, more durable, and are not costly as reinforced concrete. They can be used even in tight spaces.
- c) Wood lintels
Wood lintels are one of the most common types of lintel found in the construction industry around the world.
They are durable and easy to install but they have a limited lifespan due to their weakness when exposed to high moisture conditions.
- d) Steel Lintels
Steel lintels are one of the toughest and most durable types of lintels in construction. They are perfect for bracing walls, supporting beams, and spanning space between supports.
However, they can be very costly to buy, construct and install.
2. What is the function of the lintels?
A lintel is a type of beam that is used to support the upper wall when openings such as doors, windows, and so on are required to give a building framework.
The lintel’s primary role is to accept loads from the above wall and transfer them to the side walls.
3. What is difference between lintel and beam?
The beam and lintel are used in many different ways, depending on the type of project. In general, a beam is wider and thicker than a lintel, but a lintel may be longer than a beam.
The term “lintel” is often used to describe any wide support for an opening in a wall or ceiling.
In some cases, the lintels are spanning over door and window openings in order to resist lateral forces like wind loads or impacts that come from other sources.
Lintel systems are used in conjunction with trussed frame beams to reinforce the walls framing. The lintel is then tied into a top chord of the trussed frame.
4. What is the difference between steel and concrete lintels?
Steel and concrete have very different properties, and therefore using one over the other as part of a construction project should be considered carefully before any final decision is made on what type to use.
- a) In most cases, concrete lintel systems have been found to be directly responsible for a significant amount of construction failures. Due to the inherent instability of concrete, it should only be used in situations where the structure demands are specifically limited. For example, if a building were designed and constructed using only steel lintels over all openings, then there is no need for each individual opening to be reinforced with a concrete lintel system.
- b) Steel is more expensive than concrete but it has many advantages over wood when considering durability and strength. It is often used in industrial settings and other places where a wood building could be destroyed by fire or termites. If wood lintels are used, they must be protected with fireproof coating or the wood will burn and become useless.
- c) Steel is also resistant to corrosion, whereas concrete gets weak when exposed to acid gases like carbon dioxide or sulfur dioxide. Therefore, steel is ideal for use in buildings that are subjected to corrosive gases.
5. Where can the lintels be used?
The lintels can be used in any part of the house. It is important to place the lintel in an open space. It should be made of wood, steel, or concrete.
The material used should be light enough to not only support its own weight but also to support a beam or an opening with it.
6. How does a lintel work?
A lintel is typically used in a building’s structure to support the load on the wall where an opening is required.
It attaches to the studs that are placed on either side of the opening. It transfers their weight over to the walls, and thus prevents any sagging or other structural defects in the walls themselves from developing.
6. How is the history of lintel usage?
Lintels have been extensively used for supporting building construction since ancient times. Lintels appear in the architecture of ancient Roman, Greek, Indian, and Japanese cities.
The Roman engineers made extensive use of them as support to roof spans. Some of the most impressive lintel spans still existing today are found in Pompeii, Italy, where they support huge arches.
In medieval Europe, lintels were often used to support buildings such as the enormous west facade of Chartres Cathedral in France.
Wood was used as the main material for lintels, although in some cases stone was also used. The wood lintels were prone to the problems of moisture and decay, and therefore they have been replaced by modern materials.
In modern times, lintels are made mostly of pre-stressed concrete or structural steel. Lintel supports are sometimes made with crushed stone aggregate held together in concrete. They can be precast and placed in position by crane or other large machinery.
Lintels are usually placed over openings such as doors and windows. Lintels can also be used to support roofs or ceiling beams at those points where the ceiling itself is not strong enough to support a roof.
In lintel construction, the lintel is normally placed on top of the framing in order to provide additional strength and stability to the structure.
The weight of the lintel is transferred to the studs that are secured in place on either side of the opening.