RSJ and Steel Beam Installation Barnet

GS Renovation installs RSJs and structural steel across Barnet, from the 1930s semi-detached homes of Finchley and Mill Hill to the interwar houses of Hendon and Edgware. We open up load-bearing walls safely, from the engineer's calculation right through to building control sign-off.

In Barnet, a steel beam for one opening typically costs £1,500 to £4,000 fitted and signed off, or £2,500 to £6,500 or more for a full knock-through with the engineer's fee and making good (indicative London ranges, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Barnet.

How the job runs

1. Free site survey at your Barnet address and an itemised quote.
2. The engineer we appoint sizes the beam, and the work is registered with Barnet Council building control or an approved inspector. On a shared wall you serve the party wall notice as building owner; we supply the drawings.
3. Props go in, the opening is cut and the beam is set on padstones, packed tight above.
4. Building control inspects the steel before it is covered. We make good, and the completion certificate follows.

Removing load-bearing walls in Barnet homes

The classic Barnet job removes the wall between the front and rear reception rooms of a 1930s semi, or takes out the old kitchen wall to open up the back of the house. These interwar homes were built with a central spine wall and chimney breasts that usually carry the floor and roof loads above, so nothing comes out until a structural engineer has sized the replacement steel.

We begin with temporary propping to support the structure, then carry out staged demolition so the loads transfer gradually onto the new beam. The RSJ bears onto concrete or steel padstones at each end, spreading the load into the solid brickwork typical of Barnet's interwar stock. Once the steel is seated, packed and the connections are complete, building control inspects the work before we close everything up.

Housing in Barnet

By the valuation list's count, Barnet holds about 160,480 homes, 50% houses and 50% flats; by age, 20% were built before 1919, 34% between the wars and 46% since 1945. Where many homes are flats, a beam in a leasehold flat in Barnet needs the freeholder's licence for alterations, since the lease usually keeps the structure with the freeholder.

Three building ages under one Barnet beam, three different bearings

Barnet's houses were not built in one period, and the steel detail follows the age of the wall that carries it. 20% of the borough's homes were built before 1919, when external walls were generally solid brick laid in soft lime mortar. A padstone can bed across the full thickness of that wall, but the joints are weak, so the engineer may ask for a longer bearing or a concrete pad to spread the load. A further 34% date from between 1919 and 1939, and a house of that age may have a cavity wall instead. There the beam bears on the inner leaf and the cavity is kept clear, so damp cannot track across to the new plaster.

The difference cannot be seen from the room. Before the structural engineer we appoint draws the padstones, we open up a small patch of plaster at each end of the proposed opening. The photographs show what is really there, whether that is solid brick, a cavity, blockwork or an old timber lintel. Barnet Council's design guidance for Finchley Garden Village puts the legal side plainly: Building Regulations approval is required for any structural alterations. That requirement is national, so it applies to a beam anywhere in Barnet. Ask for the bearing inspection to be booked while the ends are still exposed.

Party wall steps for Barnet semis

In a Barnet semi the dividing wall with your neighbour, and often a shared chimney stack, sits on the party line. Where beam bearings, padstones or foundations affect that shared wall, the Party Wall etc. Act 1996 applies and you serve notice on the adjoining owner as building owner before work starts. We help you identify which walls are shared and factor the notice period into the programme from the outset.

The two-month notice period matters most in tightly built streets around Finchley, Hendon and Golders Green, where neighbouring homes share a boundary wall. Alongside the party wall notice you serve, we handle the building regulations side through Barnet Council or a registered building control approver, arranging inspections at propping, beam installation and completion. You receive the engineer's calculations and the building control certificate for your records and any future sale.

Handling and finishing the steel itself

A beam for a Barnet through-room can weigh several hundred kilos and arrives on a lorry that cannot always get down the drive. In most semis it comes in through the side passage or the front door and is moved on rollers along the hall, which is why we lift the floor covering and protect the door linings before delivery day rather than on the morning itself. Where the passage is too tight, the beam comes in through the rear.

Once seated, the steel still needs finishing. The regulations require the beam to be protected so it holds its strength in a fire, which normally means boarding it in plasterboard of the correct thickness rather than plastering straight onto the flange. Where you want a flat ceiling we set the steel up into the floor zone; where you want it visible we case and paint it. That is decided before the section is fixed, not afterwards.

• Bearing checks into party walls and shared masonry
• Temporary propping and staged, controlled demolition
• Steel columns, base plates and bolted connections

VOA Council Tax stock of properties, March 2025, for all 42 statistical areas in Barnet. Counts rounded by the VOA.

Useful next reading for an RSJ and steel beam installation project in Barnet: home renovation in Barnet, our Barnet area guide, builders in Barnet, party walls and steel beams, how we handle RSJ and steel beam installation across London and Party Wall Act Explained.

Why Choose GS Renovation in Barnet

Homeowners across Barnet trust us with structural work because we manage every stage under one roof, from appointing the engineer who does the calculations to propping, steelwork and building control sign-off. With our founder's 30+ years on the tools, we work cleanly in occupied homes and never cut corners on structure.

Reviewed jobs near Barnet

2 MyBuilder reviews from Barnet, with each customer's own job title:

• Install new kitchen, Barnet, 15 Apr 2022 (5 out of 5)
• Bathroom Refurbishment, Barnet, 14 Oct 2021 (5 out of 5)

Read all 31 on our reviews page.

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.