RSJ Installation in Home Extensions

When you’re opening up a space, removing a load-bearing wall, or building an extension, it’s common to need an RSJ (Rolled Steel Joist). An RSJ provides the strength needed to safely redistribute weight, allowing modern, open-plan layouts without compromising the stability of your home.

What Does an RSJ Do?

In most homes, load-bearing walls support the upper floors and roof. Removing one without replacing the support can lead to structural movement or collapse. An RSJ beam:

• Carries the load previously supported by the wall
• Transfers weight to strong points, like padstones or supporting walls
• Creates a safe, open space for kitchens, extensions, and living rooms

It becomes a hidden structural backbone.

Why RSJ Installation Must Be Precise

Steel beams must be installed to exact measurements. Even a few millimetres off can affect:

• Weight distribution
• Ceiling level
• Door and window alignment
• Long-term stability

This is why RSJ installation is never treated as a simple DIY task, it is a key structural operation.

Temporary Support During Installation

Before removing the wall, carpenters install temporary props and strongboys to hold the load safely. These ensure:

• No movement in ceilings or floors above
• The property remains structurally secure
• The RSJ can be placed without stress on surrounding walls

Good preparation equals safe installation.

Who Should Install an RSJ?

Only qualified and experienced builders or carpenters should handle an RSJ. The process requires:

• Correct measurements
• Structural engineer calculations
• Knowledge of building regulations
• Accurate cutting, positioning, and fixing

The beam is often lifted into place using specialist equipment, especially in extensions or larger homes.

A Safer, Stronger Home

Once installed, an RSJ allows your extension or open-plan layout to remain strong for decades. With proper support, the structure is safe, stable, and fully compliant with UK building requirements.