RSJ Installation Cost

By Kim
Last updated 16th February 2024 - Reading time: 18 mins
At a glance
  • The average cost of replacing roof tiles is around £2,000
  • The job will usually take between 1 - 2 days
In this article, you'll find out the following:
  • A breakdown of pricing information including types and sizes of RSJs and what such a task typically involves
  • How long the job will take and a general overview of what types of jobs can be performed
  • How to find and hire a specialist to install an RSJ

Want to know how much it costs to install an RSJ?

In this guide to RSJs, we look at steel beam prices for different RSJ sizes and grades of RSJ, including the costs of hiring a builder to install the steel support beams.

Typically, an RSJ installation will cost around £1500 - £2500.

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Average Cost of Installing an RSJ:

Depending on the complexity of the job, it usually takes: 1 - 2 days


How Much Does an RSJ Installation Cost?

An RSJ or Rolled Steel Joist, is a steel beam, steel girder or steel lintel. There are several types of RSJ, but the most common one by far is the "I" beam. These joists are used to support structures. Their most common use is for during building extensions or renovating buildings by knocking down walls.

Installing an RSJ may be possible for DIY enthusiasts, but the calculations required to work out the support required are difficult. Building regulations require joists to be sitting on the wall that will bear the load of any structure sitting on top of the joist.

types of rsj

It has to be sitting on a strong concrete block to distribute the weight uniformly. Any quote to install an RSJ should include calculations done by a structural engineer.

The cost of installing an RSJ will vary greatly depending on the size of the beam, your particular property, whether utilities need to be relocated, and where you are based in the UK. This includes the cost of hiring a structural engineer, plastering, skip hire, the cost for building control approval, materials, and labour for the installation.

Labour Costs and Timescales

Before getting a quote for an RSJ installation, you need to remember that part of installing an RSJ are the expert calculations required from a structural engineer. Plus, you then need a skilled builder to carry out the work properly to the engineer’s calculations.

Note also that this type of work will always create a huge mess, no matter how careful the builders are. This mess will not only require a lot of cleaning but usually also some re-plastering and re-decorating.

Most of the work can be carried out by an experienced local builder, but you will also need a structural engineer and possibly an electrician and a plumber, depending on the location of the RSJ. Most people handle the final decorating work themselves but some will also need the services of a painter and decorator.

The labour costs for installing an RSJ depend on the size of the job at hand. A single doorway 1m RSJ costs around £400 - £450 for labour, a double doorway 2m RSJ costs around £550 - £600 for labour, and a large open plan 4m RSJ cost around £700 - £800 for labour.

Hi, I want to have an RSJ replaced. Who should I hire to remove the old RSJ or should the installation company take care of this for me? I've yet to begin the process.

"The company installing should be able to arrange removal of the replaced RSJ, I would confirm this with any companies quoting for the job."
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Supply Only Costs

If you are looking for the cost of an RSJ alone, you may want to know how much a steel beam RSJ costs per metre. An RSJ costs approximately £50 - £100 per metre.

You can purchase an RSJ as supply only, however, it is not recommended that you take on the job of installing the RSJ by yourself. The calculations involved with installing an RSJ are complex and only a professional can provide the appropriate calculations on how much weight can be distributed across your RSJ.

The table below indicates the supply only costs for different elements you may need for an RSJ job.

Type of Supply Approximate Price
Universal Beams £50 - £120 per metre
Universal Columns £50 - £120 per metre
Double Beams £50 - £100 per metre
Parallel Flange Channel £30 - £100 per metre
T-Beam £8 - £20 per metre
Lintels £16 - £22 per metre
Special Lintels £40 - £60 per metre
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Additional Costs

There are a number of additional costs that may come up during an RSJ installation job. The main additional costs that may pop up with this type of work are listed below:

  • Wall demolition - The average cost of removing a load-bearing wall is typically £1200 - £1750.
  • Skip hire - A one-week skip hire will cost you around £200 - £250.
  • Re-decorating – Re-decorating a small room will cost around £150 - £160 per day.
  • Re-plastering – Re-plastering a small room will cost around £390 - £510 and should take no more than a day.
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Cost Factors of Installing an RSJ

There are several factors that may affect the cost of your RSJ installation cost. This can include the size of the RSJ, the location of your home, ease of access to your property, and whether utilities need to be moved.

The size of the RSJ can affect the installation. The bigger the RSJ beams, the more the total job is going to cost. The RSJ costs around £50 - £100 per metre and so you can see how the length of the beams needed can greatly affect the overall cost of the job.

The location of your home can affect the cost of an RSJ installation. If you live in London, you can expect to pay around £200 - £300 more for the RSJ installation than if you were to live in the north of the UK.


The ease of access to your property can affect the cost of and RSJ installation. If your property is difficult to access, the installation will take a lot longer to complete than if your property is easy to access. This will result in the overall cost of the job being higher due to the additional labour costs and the extra complexity of the job.

If utilities need to be moved in order to install the RSJ, you may need to think about the additional costs of hiring a plumber or an electrician. A plumber tends to charge around £30 - £50 per hour for their work and an electrician usually charges around £25 - £40 per hour for their work.

Benefits of an RSJ

There are a number of benefits to installing an RSJ. The main advantages of installing an RSJ are listed below:


Steel is well-known for being eco-friendly. That is why steel is used for a lot of building projects. There are no limits on the number of times that RSJ beams can be recycled. This means that there is a lot less waste than if other materials were to be used instead.

Steel is also regarded as being very eco-friendly because it doesn’t emit any greenhouse gases. Steel RSJ beams are extremely cost-effective in comparison to other materials, such as wood and concrete.


Steel is incredibly strong. It is capable of bearing more weight and stress without compromise than a beam made out of alternative materials, such as concrete or wood.

Modern buildings are often constructed with steel frameworks because they are incredibly strong and able to withstand extreme weather conditions, such as earthquakes and hurricanes.


RSJ steel beams are incredibly durable. Wood and concrete beams are nowhere near as tough in composition as steel. Steel beams are also resistant to fire, don’t require any chemical treatments, and are also resistant to termite damage.


Steel can last for an incredibly long time, especially in comparison to other materials. The load-bearing design of RSJ steel beams means that they are basically indestructible to constant weight.

Types of RSJ

There is a wide range of different RSJ beams available. The following list explains a little bit about each of the different types and the pros and cons of each.

Universal Beams

Universal beams are good for many different types of construction. They are safe and durable and come at a low cost.


They are often referred to as ‘I’ beams due to their ‘I’-shaped appearance. Universal beams are most commonly used horizontally in building structures to support floors or roofs.


  • ✔ Safe
  • ✔ Durable
  • ✔ Low-cost
  • ✔ Lightweight
  • ✔ Flexible


  • ✖ Can rust over time
  • ✖ Can weaken over time
  • ✖ Conducts heat

Universal Columns

Universal columns are great for a variety of construction purposes. They are safe, durable and eco-friendly, and come at a low price in comparison to other materials.


Universal columns are commonly referred to as ‘H’ beams due to their ‘H’-shaped appearance. Columns are mainly used in structural applications.


  • ✔ Safe
  • ✔ Durable
  • ✔ Low-cost
  • ✔ Recyclable
  • ✔ Lightweight


  • ✖ Can weaken over time
  • ✖ Conducts heat
  • ✖ Conducts heat

Double Beam

A double beam is similar to a universal beam, only the beam part is doubled. This makes this beam stronger and it can withstand more weight. Double beams are used for similar purposes as a universal beam to support floors and roofs.


  • ✔ Safe
  • ✔ Durable
  • ✔ Low-cost
  • ✔ Lightweight
  • ✔ Flexible
  • ✔ Extra Strong


  • ✖ Can rust over time
  • ✖ Can weaken over time
  • ✖ Conducts heat
  • ✖ Bulky


A channel is a C-shaped beam and comes in a wide variety of sizes and thicknesses. The shape of this type of beam provides superior structural support.


This makes it an ideal product for using for frames and braces on buildings and structural support applications.


  • ✔ Strong
  • ✔ Safe
  • ✔ Durable
  • ✔ Superior structural support


  • ✖ Can rust over time
  • ✖ Can weaken over time
  • ✖ Conducts heat


A T-beam is most commonly constructed using a reinforced concrete. Sometimes, isolated T-beams are constructed to increase the compression strength of concrete. T-beams offer an extra layer of strength for structural purposes.


  • ✔ Adds extra strength
  • ✔ Better head room
  • ✔ Structural support


  • ✖ Requires strong bonding
  • ✖ Can become weak
  • ✖ Can develop cracks


Lintels are horizontal beams that are placed over doors and windows. These can be made from timber, stone, brick, steel, or reinforced concrete.


  • ✔ Protects doors and windows
  • ✔ Safe


  • ✖ Can become cracked
  • ✖ Can weaken over time

Do I Need an RSJ?

Building any kind of structure is a complicated process as there are so many things that need to be considered.

If you are considering taking a wall out of your home, it is important to consult with a building company or a structural engineer.

This professional will then come out to inspect your home to see what you are looking to do and advise on the correct procedures needed to carry out a safe job.


This includes support of the ceiling and roof. If you are planning on taking a wall out, you will most likely need to put an RSJ in its place to support the upper floor. A rolled steel joist will support the area above the wall you are taking out similar to how the wall was when it was there.

If you are unsure if you need an RSJ for any work that you are carrying out on your home, you should consult with a building professional or a structural engineer. They will be able to advise you as to the best route to go down when it comes to renovating your property.

What is a Load Bearing Wall?

A load-bearing wall is a wall that is an important structural element of a building. This means that it bears the weight of the elements of the wall above it.

The above wall rests on a load-bearing wall by conducting its weight to a foundation structure. Load-bearing walls typically run parallel to the ridge.

Building Permission Installing an RSJ

If you are creating a new building, installing fittings or windows, extending or structurally altering an existing building, you will need to gain building regulations approval. This is not the same as planning permission.

Depending on the type of building you are working on, and the type of work that you are carrying out, you may also need to gain planning permission.

If you are the owner of the property that is having work done, you are responsible for ensuring your builder complies with building regulation rules.

All calculations for RSJ beams must be sent to a building control officer who will sign off the building regulations approval.

The building control officer will check that the calculations and provisional building work plans comply with the building regulations.

Can I Install an RSJ Myself?


Installing an RSJ is definitely not a DIY project. It should not even be attempted without hiring a structural engineer first for the necessary calculations to determine the correct size of steel beam required.

A structural engineer will be a requirement for building regulations approval and then the actual installation should be done by an experienced builder.

This is because if there are any mistakes or corners cut, you could compromise the structural integrity of the property.

There are some parts of the job that you may be able to complete yourself in order to save some money, such as removing waste or re-decorating.

However, the main aspect of the job should be left up to the professionals to ensure that everything is done correctly and to ensure that the completed job is safe.

If you are a qualified builder yourself, you may have the right knowledge and experience to carry out the work yourself.

If this is the case, you will still need to obtain the relevant building regulations approvals. However, you could save around £400 - £800 on the cost of labour.

Cost of Removing an RSJ

You may want to remove an RSJ if you are re-building a supporting wall, or if you are knocking down the wall above the steel beam. Another reason you may want to remove an RSJ is to replace it with another one or to replace it with a different kind of support beam.

Removing an RSJ is not an easy job and should be done safely and with great care. If you are unsure of what is required of the job when choosing to remove an RSJ, you will need to consult with a structural engineer to advise on the best method for removing your rolled steel joist.

If you are removing a rolled steel joist, you will need to consider if you need to replace it with some other kind of support. If there is still a bearing load above where the RSJ was, you will need to replace the RSJ with some other form of support, such as a wall or another support beam.

A builder will charge you around £20 - £35 per hour for the labour of removing your RSJ. There are also some other costs that may become involved in a job of removing an RSJ.

Waste removal is something that you may need to think about. A one-week skip hire will cost you around £200 - £250.

Re-decorating a small room will cost around £150 - £160 per day. Also, re-plastering a small room will cost around £390 - £510 and should take no more than a day.

Hiring an RSJ Installer Checklist

There are a number of points that you will need to consider when hiring an RSJ installer. Below are some of the major things that you should think about when looking for the right contractor or company for the job:

  • Do you have the correct measurements as taken by a structural engineer to complete the job?
  • Have you or your builder acquired the relevant building regulations approval?
  • How many years’ worth of experience does the builder or company that you are looking to hire have?
  • You should gather at least three quotes so that you can compare them and to ensure you are paying an appropriate cost for the work at hand.
  • You should ask for a cost breakdown on your quotes so that you can ensure you are paying a good price for each of the different elements of the job.
  • Does the builder or company you are hiring offer any guarantees or warranties with their work?
  • Does the company offer additional services such as cleaning up, waste removal, re-plastering, and re-decorating?


What does RSJ stand for?
RSJ stands for ‘Rolled Steel Joist’.
What are the standard sizes of RSJs?
Below is a list of common RSJ beam sizes. These particular sizes are commonly used in domestic properties.
RSJ size Depth (mm) Width (mm) Weight (kg/m)
152x89x16 152.4 88.7 16
178x102x19 177.8 101.2 19
203x102x23 203.2 101.8 23.1
203x133x25 203.2 133.2 25.1
203x133x30 206.8 133.9 30
254x146x31 251.4 146.1 31.1
254x146x37 256 146.4 37
254x146x43 259.6 147.3 43
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Why would I need an RSJ?
An RSJ is needed whenever you are planning to remove a load-bearing wall. As you will always need something in place to support the weight from above, an RSJ will act as the relevant support needed whenever a supporting wall is removed.
What is a Pad stone?
A pad stone is a concrete or stone block that is used to distribute weight evenly within a structure. In modern architecture, pad stones are typically used to distribute a load evenly at points where the lintels and the end of beams are built into a wall.

Pad stones receive a concentrated load and so reduce the risk of materials below from becoming crushed or cracked.
How much does it cost to knock down a wall and put in an RSJ?
The cost to have a wall removed and an RSJ put in place will vary depending on the size of the wall and the size of the RSJ that you are having installed. Typically, an RSJ installation will cost £1500 - £2500 in total.
Is installing an RSJ a DIY project?
No – The job requires a structural engineer as an absolute minimum. However, a professional builder is also highly recommended. There are a lot of safety implications when it comes to structural jobs. You can, however, choose to re-decorate yourself to save some money.
Do I need building regulations approval for an RSJ installation?
Yes, you will need building regulations approval as you are structurally altering or extending a building. Installing RSJ beams requires building regulations approval as a minimum.

However, you may also need planning permission depending on the type of work that you are carrying out and the type of building that you are working on. The calculations and plans that are completed by a structural engineer will need to be provided to the building control officer for approval.
How can I identify a load-bearing wall?
Load-bearing walls are an important part of the structure of a building. A load-bearing wall will support the roof structure, upstairs walls, floor joists, or will provide lateral support to tie the adjoining walls together.

It is not as easy as some people may think to identify a load-bearing wall. If you are unsure, it’s a good idea to call in a structural engineer or building inspector to inspect the wall in question before you begin to remove or alter any internal walls.


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