Modern construction has come a very long way since its inception during the Industrial Era. New forms and methods gave rise to faster and more advanced forms of construction. Today, the formwork and shuttering equipment that had already been around for a long time are being mass-manufactured, which has led to large scale construction activities happening at rapid speeds.
Formwork is essentially a temporary mould that is used to pour and cast concrete. They are usually made of steel, wooden boards or plastic and other durable materials which can stay in place and not budge during the casting process. Formwork is used to attain the desired shape and volume of a horizontal element like the beam or slab. It keeps the concrete in place and assures a predetermined strength and shaped formwork is held upright with the use of poles to support the slabs and beams where the poles are pushed under them to maintain the element’s position and keep it upright. This is known as ‘formwork staging’
Shuttering is temporary formwork for vertical elements and is used to keep them upright and sturdy. Shuttering means using steel moulds to cast these vertical elements that hold the concrete up and provide a specific shape. It is used for columns, walls and other vertical members. In the process of shuttering, the vertical formwork is held up with the use of poles or metal/ wooden rods that are pushed up against the formwork of vertical elements like walls or columns. These rods and poles are placed diagonally to provide proper resistance against the load of the structure that it is holding and support the outer formwork.
This process is known as ‘shuttering staging’. To know more about this, www.formworkcontractorsbrisbane.com.
In both cases, it is important to use waterproof materials that are durable and have the capability of taking the stresses and loads without deflecting or deforming.
- Steel Formwork/ Shuttering: Even though steel can be expensive, it produces excellent casting results. Being extremely durable, its strength is much higher than other materials. Steel is also very versatile as it can be reused 10 times more than timber formwork and provides a perfect outer finish to the casted element. It also prevents water absorption and is easy to handle.
- Timber Formwork/ Shuttering: Economical and sustainable, this formwork is usually used for much smaller projects like residences. It can be reused 10 times and is light in weight, making its workability extremely good.
The only drawback of using timber formwork is that it is capable of absorbing water and forming knots. Using chemically treated timber would negate this issue.
- Plywood Formwork: Using plywood which is nothing but the engineered wood is a very popular and probably the most common form of formwork that is being used. Plywood is light, inexpensive and possesses the strength of steel and the sustainability of wood. Being extremely versatile, plywood can be reused up to 25 times and they produce great overall results.
Since it is wood that has been treated, it is less likely to absorb water as compared to traditional timber and also does not have knot formation capabilities. It is also easy to install and dismantle.
Formwork enables the construction of multi-storied commercial buildings like malls and complexes, residential buildings and infrastructure like multi-storey car parks and factories. Over time, framework and shuttering have become an integral part of any type of construction and have made the construction process easy to implement with great reliability and quality.
Page Contents
Types of formwork- the detailed look
First of all, when choosing formwork, you need to pay attention to the kind of concrete and the pouring temperature—they will both impact the pressure. Additionally, formwork has to resist loads of both dry and wet concrete.
Typically, formwork needs elements like stabilizers and poles to reduce the risk of movement during building processes; they’re commonly known as falsework. To ensure that the results will be of high quality, supervision and qualified professionals need to do the job.
Here’s a close look at the materials commonly used for formwork.
Timber
Timber formwork has been one of the primary kinds used in construction. It impresses with the flexibility and can be put together on site. The benefits for timber formwork are:
- It’s easy to make and remove
- It’s effortless to work with and can take any shape, size, and height
- It’s easy to make and remove when no longer necessary
- It’s affordable for the small projects
- Local timber can be used, if available
When working with timber, several aspects have to be checked out for termites. Additionally, timber isn’t long-lasting and requires time for assembly, which doesn’t make it a good choice for large projects.
If labor spending is low and the complex concrete sections require highly flexible formwork, timber formwork is the best option.
Plywood
It’s expected that plywood is used together with timber. Plywood is a manufactured wooden material, so it comes in various thicknesses and sizes. Sheathing, decking, and form linings are the most common projects when plywood formworks are used.
Plywood formwork presents properties similar to timber formwork, especially when it comes to lightweight, strength, and durability.
Metal
Steel
The versatility and long lifespan make steel formwork and steel hardware popular for construction work. Even if it’s expensive, steel formwork is highly dependable for various projects. It’s the no.1 choice for jobs where reuses are common.
Steel formwork presents several benefits:
- It’s waterproof
- It gives a smooth finish to the concrete surfaces
- It’s strong and long-lasting
- It’s adequate for curved structures
- It reduces the risk of the honeycombing effect of concrete
- It’s easy to put together and to take apart
Aluminum
Aluminum formwork resembles steel formwork. The most crucial difference between the two is that aluminum has a lower density than steel, which explains the lighter weight of aluminum formwork. Additionally, aluminum is weaker than steel, so make sure it can take the load you need.
Plastic
Modular systems or interlocking panels are used to assemble plastic formwork. The plastic is solid and lightweight, which is why plastic formwork is ideal for small projects. Repetitive tasks like affordable housing estates are such projects.
Plastic formwork is light and easy to clean with water. Professionals use it for large sections and multiple reuses. The most crucial downside of plastic formwork is that it’s less flexible than timber, as many elements are prefabricated.
Fabric
Fabric formwork, aka flexible formwork, is made with solid and lightweight sheets of fabric that are made to adjust to the concrete’s fluidity. It helps when creating unique architectural forms.
Fabric formwork uses less concrete than other systems, which explains the low price. It’s a relatively new technology, and it’s adequate for constructing complex and intricate shapes.
Stay-In-Place Formwork
This formwork is made to stay in place once the concrete has been set; it works as shear and axial reinforcement. Prefabricated and fiber-reinforced plastic forms are used to make stay-in-place formwork. Commonly, it’s used in columns and piers as it offers resistance against environmental damage and corrosion.
Coffer is also within this category and works for any building. It comes two filtering grinds and stiffeners for reinforcement, whereas articulated connectors are used for the connection. Thanks to its construction, it’s easy to carry from the factory to the construction site.
Permanent Insulated Formwork
It’s the most advanced formwork system and ensures permanent insulation. It can also present fire-resistance, thermal, acoustic, and rodent-resistance abilities. Insulating concrete forms (ICF) are the most common permanent insulated formwork, where polystyrene boards are used for insulation once the concrete has cured.
Permanent insulated formwork gives sustainability and energy efficiency and reduces the environmental impact of the construction industry.
Structural components also lead to various types of formwork
Material is one factor to consider when differentiating formwork. According to the building elements that they support, formworks can be:
- Beam formwork
- Wall formwork
- Column formwork
- Foundation formwork
Formwork types are made according to the structure they have to support and the construction plans. Materials and necessary thickness are also factors to weigh in when making the formwork. Formwork construction does take time and makes for 20 to 25% of the spending for structure. If you want to reduce the expenditure on formwork, you can keep in mind some suggestions:
- Reuse building elements and geometries as much as possible so that you can reuse formwork
- The design and purpose of concrete structures vary a lot. Always go with the formwork most suited for your project.
- Cut the timber formwork large so that you reuse them.
Should you use wooden plank shuttering?
Wooden planks shuttering are popular due to their low price and availability. However, the shuttering impacts the strength of concrete and comes with downsides.
- It’s not water-tight because the thickness and size of planks vary a lot. As a result, water and cement go to the ground from joints and decrease the concrete’s strength.
- As cement slurry leaks through joints, earthwork below will set in and cause more problems
- Sometimes, wooden plans cannot bear the concrete’s weight. Since they’re weak, wooden planks tend to deflect and bend, and even break.
Temporary brick masonry shuttering
Sometimes, contractors use Temporary Brick Masonry in mud for vertical support of sides of fascia, beams, etc. However, we don’t recommend its use. This shuttering decreases the strength of cement concrete as it soaks cement slurry. Additionally, compaction isn’t adequate, and the shuttering cannot bear the vibrator’s pressure. The cement concrete surface made with this shuttering isn’t even, and the plaster is too thick.
Frequently Asked Questions
Formwork is necessary for placing concrete. Why is so?
Formwork serves as a mold for structural elements made of concrete. It has to be available when the concrete mix and needed steel reinforcements are set in. Formwork has to be strong so that it supports the structure it’s made for.
How do you recognize good quality formwork?
Suitable formwork is strong enough to withstand the weight of concrete during placing and compacting. It has to support any other loads that are necessary. Additionally, a good quality formwork is easy to erect and struck.
Which type of shuttering is best?
The steel shuttering plate represents the best kind of shuttering as the water-tight shuttering bears a load of cement concrete placed on it. The shuttering is reliable for vertical, horizontal, and any other shape necessary for the jobs. It will create a leveled surface with an excellent finish.
How to calculate for formwork?
If you need rectangular and square forms, you have to multiply length and width to see how much formwork is necessary. In the case of a circular shape, you have to bear the square of the radius by pi. Break irregular shapes into simple rectangles and squares and add the results for the total surface area.
Is there a difference between shuttering and scaffolding?
Scaffolding is a temporary structure that offers a platform at various building levels for materials and workers. Formwork, though, is a temporary structure that serves for molding when pouring the concrete.
