The Cost Of Installing An RSJ Support Beam

Find out the costing involved with installing an RSJ support beam. We’ll discuss and cover the cost for different steel beam prices, along with the different sizes and the costs for hiring a builder for installation. See the different types of RSJ’s and when it’s time to use one.

What is an RSJ and what are they used for?

RSJ stands for Rolled Steel Joist. The purpose of an RSJ support beam is used for structural steelwork. They’re shaped like I or H letters. Which can also be their names as some people refer them by. The “I beam” is the most common type. Learn below the many types of RSJ support beams.

Ultimately, an RSJ is the support beam for supporting the weight of a ceiling. In most cases, they’re used for taking out a supporting wall and replacing with an RSJ in its place to hold. However they’re used as structural support for many different constructions. The most common use is for a load-bearing wall.

Load-bearing wall

Supports the weight of a roof structure or floor. It’s called a load-bearing wall because they bear a load. A non load-bearing wall, which is sometimes called a partition wall, is dependent only on holding up itself.

Check with a structural engineer to determine whether a wall is load-bearing or not. You can do some simple checks and tap the wall to see if you can hear a hollow sound. Though, this may not be the final answer in finding out if it’s load-bearing or not. If the wall runs at a 90-degree angle to the joists, then it’s said to be a good chance that it is load-bearing.

Situations when needing an RSJ

An RSJ is useful for those projects that need a wall replacing or for general support for structural steelwork. You could help save the house in the long run by upping the home value by adding in extensions or alternating a room for the good.

For example, if you’re trying to do an extension in the home or you’re trying to make one room bigger than it originally was, an RSJ installation will be worth it. You can then add in decorating trends or display features for the extra space.

The most common feature of including an RSJ is by extending the kitchen through to the dining room. It provides a much bigger space to roam around in the room and provides a relaxing dining experience.

Of course all homes are different in layout so you may be limited to what you can do. But be creative and get yourself an extension for your home. It may be the turning point in increasing the home’s value.

How much does installing an RSJ cost?

The average cost of an RSJ installation is said to be around £1000 – £1300.

Breaking it down – cost for materials, tradesmen and waste removal. There are other costs to consider which is mentioned below. But these three factors are the main source to look at.

RSJ installation prices: (These prices may vary with different providers)

  • Single doorway 1m RSJ – £200 for materials – £400 for labour cost.
  • Double doorway 2m RSJ – £300 for materials – £600 for labour cost.
  • Large open space 4m RSJ – £500 for materials – £800 for labour cost.


Tips on how you should prepare: (These prices may vary with different providers)

  • Structural engineer costs – £200 to £300
  • Labour costs £400 – £800
  • Skip hire – £120 – £180
  • 6m RSJ – £700
  • Building inspector – £150 – £200

Installing an RSJ – The only way would be to go through a structural engineer or a building company to ensure everything is done right and pay for the installation.

For DIY devotees wanting to limit down on spend. Unfortunately this isn’t achievable to do so on your own. There’s a lot of things to consider when installing an RSJ.

You will need the calculation required from a skilled structural engineer before proceeding and approval from the building control. Plus, you will need a building approval certificate which is essential.

A structural engineer will calculate the correct load which is needed for the support, and will then pass this information onto a skilled builder, who will then liaise closely with a steel fabricator to manufacture the RSJ to suit the correct fit. This will all then be signed off, delivered, and made ready for project structural work.

General sizing of the RSJ and the type of beam can be correctly measured by a structural engineer using the length of the beam, and the details of the load it has to bear.

This type of work without professional help can risk the element of the house.

Planning permission to install an RSJ – Rules and regulations change from time to time, so it’s important to check with the planning department before any RSJ installations are taking place. 

Other cost factors to consider

You’ll first begin by getting a quote from experts in structural engineering and a skilled builder for RSJ installation. But what are the other costs that will come into place?

The work will naturally grant a lot of mess in the room and will require plenty of cleaning. This will lead onto some replastering and redecorating in the room as well.

A skilled builder and structural engineer in your local area will most likely take care of most of the work. But there can be cases where a plumber and electrician is needed. You can take care of the final pieces of decorating work that is needed yourself, but you may require services from a painter and decorator to clean up the rest.

More possible costs involved would include: New carpets or flooring to be fitted, relocating or installing a radiator, power sockets and light switches moved, and wall agreement legal costs if relevant.

Different types of RSJ

  • Single beams
  • Double beams
  • Lintels
  • Steel girder
  • T beams


It may be overwhelming at first with the different types of stages you need to go by in order to get the RSJ installation on the go. But it could help save the house in the long run by upping the households value.

An RSJ allows you the freedom of rearranging and planning out the layout and structure of your home.

Get a Quote on RSJ Installation

Not sure whether you need an RSJ fitted in your home for the work you’re about to have done? We can help. If you fill in the form below we will be able to provide you with advice & compare quotes to give you the cheapest possible price:

About Steven

An enthusiast of DIY and household ideas. I've experience my fair share of tough projects in my time and have learnt a lot along the way. I enjoy a good DIY challenge, sharing my experience & research.

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