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What Are RSJ Goalpost And Box Frames

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  • Admin
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  • Goalposts, Box Frames, Construction
  • Posted date:
  • 10-08-2022
What Are RSJ Goalpost And Box Frames

What are RSJ goalpost and box frames? Find out why an RSJ frame would be needed and when to use  goalpost and box frames.

What are Goalposts and Box Frames?


A goalpost frame is comprised of two columns that have been bolted to a horizontal beam at the top. The two columns are welded to the top beam to prevent the structure from deflecting sideways. This reinforcement supports the weight of a building caused by construction materials, furniture, and people.

For example, if you want to add a ground floor extension to a property, you would need to support a new flat roof with a goalpost frame. This goalpost frame will prevent the wind and weather from affecting the building's movement. 

Box Frames

Similar to goalposts, box frames have a bolted beam at the top of the frame that weld two columns together. If the foundations of a property are strong enough to support the weight above the frame, box frames are highly beneficial for removing walls from the property in question.

The difference between goalposts and box frames are ground beams. The ground beam is found on the bottom of the box frame and is useful for spreading the weight of a building along its length. The ground beam is installed below ground level and requires protection from rust and corrosion.

In most domestic cases, the ground beam is covered by concrete to protect it against water. In contrast to galvanisation, the concrete that many homeowners use to protect ground beams provides a cheaper addition to the frame's structural integrity and strength.

(Galvanisation is an expensive method of coating steel in a layer of zinc to protect the steel from corrosion.) 

Do I Choose a Goal post or Box Frame?

If you find that a steel beam is not sufficient enough at supporting your property, you may need to install a box frame or goal post. For example, when creating a larger ground floor opening, you may wish to install a goalpost to support the ceiling above so that safe construction can begin.

Installing goalposts may require new foundations to counteract the eccentric loading, which in turn requires a higher budget and leads to a longer construction time. You could either lay new foundations with your goal posts or install box frames for a more comprehensively supported structure that spreads the load without overstressing the soil/foundations.

What Are RSJ Goalpost And Box Frames?

Aside from the increased cost of steelwork, the strength and structural integrity that steel box frames provide surpass that of goalposts. Steel box frames allow for maximum openness and modern interior designs if they become permanent features of your property. Goalposts can have one or more cross beams depending on the construction project.

A cross beam is a structure where two steel beams are connected via right angles. A goalpost with one cross beam is used when removing two walls, whether it's taking out the back wall of a property or removing a partition wall between two rooms. The end of the adjoined beam sits on a supporting wall and there is no need for a base beam because the structural loads don't require it.

A goalpost with two cross beams tends to be used when a construction project includes taking out multiple walls within a property. Alternatively, if you want to remove the main wall of a building but the ceiling span is too large for a singular beam to support it, a goalpost with two cross beams can support it.

Do I Choose A Goal Post Or Box Frame?

Similarly to a goalpost with one cross beam, the two cross beams are supported at their open end by a supporting wall. There can also be two goalposts bolted together by a single cross beam that is extremely useful for when you want to take out two walls in a property.

Having the double goalpost structures at opposing ends stabilises both the structure of the entire building and the ground floor. If a goalpost or two are not strong enough for the expected load, you need supporting, or you require higher lateral stability, it is worth choosing a box frame.

The load from above and the sides are transferred through the two columns to the bottom beam and surrounding foundation. Additionally, if there is no party wall agreement between you and your neighbours, a box frame must be used instead of any other steel framework.

Why would an RSJ Frame be needed? 

Goalpost frames or rolled steel joist (RSJ) box frames are two design solutions that will provide support against loadings and horizontal loadings.

Loadings refer to the factors that weigh down a building, such as furniture installations and people. On the other hand, horizontal loadings account for the sideways forces such as wind or external pressure from other structures.

Depending on how much support your property requires determines the type of structure you should consider installing.

While both frames feature a top beam in their structure that splits the horizontal loadings equally, the bottom beam in RSJ box frames provides extra firmness against horizontal forces. 

Why Would An RSJ Frame Be Needed?

Goalpost vs Box Frame

When it comes to deciding which structural frame to use, it is important to choose the frame type that best suits your construction project and property. Goalposts and box frames can be temporary supports or permanent features inside your property.

If you want to permanently alter your building, you should choose an equally strong and durable frame that will continue supporting your building even after construction. Goalposts are attached to square, rectangular, or circular concrete/foundational slabs for structural support, whereas box frames have their ground beams encased in the concrete and/or foundation for combined firmness and strength.

This framework is commonly used when a supporting beam is needed, but the property's load-bearing walls demand more support. 

 Box frames are usually used when removing a wall, supporting the building where the wall has been removed, and the ground beam resides. 

The lesser-known benefit of steel box frames is that they help minimise groundwork by providing a comprehensive and strong structure.

Goalpost Vs Box Frame

The erection of structural steelwork consists of assembly, lifting, positioning, and connecting. 

Compared to most groundwork jobs that involve a lot more preparation, installing box frames can save a lot of time and money than alternative methods and processes. Another reason steel framework saves time is if you have a structural engineer ready on-site to weld the framework together.

Regarding goalposts and box frames, remember that it depends on the internal space of where the construction project will take place and how much loading you need support for. 

 If you require more help with which steel framework to choose, a structural engineer or principal contractor can be hired to best assess your construction project and deliberate on the best framework to install on your property. 

Are you looking for RSJ steel beam suppliers in London, Kent, Essex and the surrounding areas? Follow the link below to discuss your project.