Key Takeaways
- Removing a load-bearing wall and installing an RSJ typically costs £2,500 to £6,500+, with a simple 3 m beam from around £2,500 all-in (MyBuilder / Checkatrade 2026).
- Installed steel beams cost roughly £300 to £600 per metre; supply and install combined runs £225 to £570 per metre.
- A structural engineer is always required for calculations, so budget £300 to £500.
- The work needs Building Regulations approval and Building Control sign-off, not planning permission.
- If the wall is shared with a neighbour, the Party Wall Act may apply and notice must be served.
Removing a load-bearing wall is the single most transformative change you can make to a London home, turning dark, boxy rooms into bright, open-plan living space. This guide explains what it costs in 2026, how to tell if a wall is load-bearing, the building regulations and party wall rules that apply, and exactly how the process works.
How much does it cost to remove a load-bearing wall?
Removing a load-bearing wall and installing a steel beam typically costs £2,500 to £6,500 or more, with a straightforward 3-metre beam in a terraced house starting around £2,500 all-in, according to MyBuilder and Checkatrade 2026 data. Installed steel beams cost roughly £300 to £600 per metre, and supply and installation combined runs £225 to £570 per metre once labour, lifting and fixings are included.
| Item | Typical cost |
|---|---|
| Steel beam (supply only) | £50 to £120 per metre |
| Supply & install (combined) | £225 to £570 per metre |
| Structural engineer's calculations | £300 to £500 |
| Simple single-beam knock-through | from £2,500 |
| Wider opening / double beam | £4,000 to £6,500+ |
What is an RSJ?
An RSJ, or rolled steel joist, is the steel beam that carries the load once a supporting wall is removed. When you take out a load-bearing wall, the weight it was holding, whether floors, walls or roof above, has to be transferred to a beam and down through new supports at each end. Getting the size and bearing right is a structural calculation, not a guess, which is why an engineer is always involved. You may also hear the terms UB (universal beam) and UC (universal column), which are the modern designations for the steel sections used.
How to tell if a wall is load-bearing
You should never assume, but there are strong indicators. A wall is more likely to be load-bearing if it:
- Runs at right angles (perpendicular) to the floor joists above.
- Sits directly above another wall, beam or steel on the floor below.
- Forms part of an external wall of the house.
- Is built in solid masonry (brick or block) and is noticeably thicker than a stud partition.
- Supports the ends of joists, a staircase or a roof structure.
By contrast, a thin stud partition that runs parallel to the joists is often non-load-bearing, though it can still carry services or bracing. The only safe way to be certain is to have a structural engineer or experienced builder inspect it, ideally lifting a floorboard above to check the joist direction.
Do you need building regulations approval?
Yes, always. Removing a load-bearing wall requires Building Regulations approval, regardless of whether you need planning permission (you usually do not for internal structural work). The process has two non-negotiable parts:
- Structural engineer's calculations to specify the correct beam size and its supports, budgeted at £300 to £500.
- Building Control inspection and sign-off, where an inspector checks the steelwork before it is concealed and issues a completion certificate.
Beam types, padstones and goalposts
The engineer's design determines not just the beam but how it is supported. A few terms worth knowing:
- Padstones: high-strength concrete or steel blocks that spread the beam's load into the masonry at each end. Skipping or undersizing these is a common cause of cracking.
- Goalpost frame: where the wall below cannot take the load, vertical steel posts are bolted to the beam to form a goalpost, carrying the load to the foundations. This is common in wider openings and side-return extensions.
- Single vs double beams: wider spans or heavier loads may need two beams bolted together, which increases cost and the lifting equipment required.
Do you need a party wall agreement?
Possibly. If the wall is shared with a neighbour, or you need to cut into a party wall to seat the beam, the Party Wall etc. Act 1996 applies and you must serve formal notice on the affected neighbours before work starts. This is common in London's terraced and semi-detached housing. Notice periods and a party wall award can add a few weeks, so it is best handled early. We help coordinate party wall matters as part of the project.
The step-by-step process
A typical single-beam job takes 3 to 5 days on site once the calculations and approvals are in place. The sequence is carefully controlled because the structure is temporarily unsupported during the works.
- Survey & engineer's calculations, where the beam is sized and specified.
- Building control & party wall notices arranged in advance.
- Temporary propping installed to support the load safely.
- Wall removed and opening cut for the beam bearings.
- Steel beam seated on padstones and bolted or welded as specified.
- Building Control inspection before the steel is encased.
- Making good, including plastering, fire protection and finishing.
Can you remove a load-bearing wall yourself?
No. This is one job that should never be a DIY project. Without engineer's calculations, temporary support and building control sign-off, removing a load-bearing wall risks collapse, cracking and serious injury, and it breaches Building Regulations. It will also surface as a problem when you sell, because solicitors ask for the paperwork. GS Renovation carries out RSJ installation and structural alterations across all of London, fully compliant with building control. For a free, no-obligation quote, get in touch or call 07472 424 226. Opening up to a kitchen-diner? Read our kitchen renovation cost guide too.