RSJs are the reason your home extension will stay up! If you are considering any major structural changes or removing a load-bearing wall, you will need a Rolled Steel Joist (RSJ) installed.

RSJs are the most popular steel beams being used in construction today. There are two types, one has an ‘H’ cross section the other is known as an I-Beam. Both are highly durable and can be cut to any size, which makes them perfect for supporting the floors and ceilings in any home extension.

When a house is built, load-bearing and non load-bearing walls are created. The difference is that load bearing walls are responsible for supporting the structural weight of the entire building while non-load building walls are there purely to divide rooms. 

If you want to create an open plan space by removing or modifying a load-bearing wall you will need to insert a steel RSJ beam to take the strain, or your house will literally fall down as it will be missing key critical supports.

Installing an RSJ correctly requires careful calculations, time and skill. An experienced builder or structural engineer will need to inspect your property and perform steel beam calculations to consider what type of wall they are working with, what length of beam they need and how much weight is going to be supported by the beam.

The cost of installing an RSJ can vary greatly depending on regional price differences between suppliers, the size of the beam and the ease of access to your property.  Often, an RSJ beam can be hoisted into place but really heavy beams, or difficult to reach sites, might need to use a crane.

Additional costs of installing an RSJ can crop up once a wall has been removed. These can include:

• ‘Making good’ uneven flooring– often the floors on either side of the original wall may not be level and this will need to be fixed.
• Cost of redecorating. Removing walls is a messy business.
• Party Wall agreements. If you are altering a structure that could potentially impact an adjourning property, you will need a legal agreement that will protect your neighbour and you from any disputes over damage that may occur during construction.

All drawings and calculations for any steel beam work will need to be submitted to Building Control to gain Building Regulations approval and an experienced builder will be able to do this for you.

It’s pretty common to see RSJs in both older and newer houses these days but don’t think the planning for them is commonplace. Make sure you consider the impact of removing a wall and who you trust enough to do this well if you are thinking of a home extension.