Structural Work & Steel Beams

The consequences of poorly executed structural work range from failed building control inspections (which means you can't sell the property without indemnity insurance or retrospective approval) to genuine safety hazards. A steel beam that's undersized, poorly supported, or installed without adequate bearing can fail under load — and the results are catastrophic.

Common problems we see from cowboy structural work: beams resting on single-skin brick walls without padstones (the brick crushes under point loading), undersized steels that deflect visibly under load, Acrow props left in place permanently because the beam was never properly installed, and foundation underpinning done in the wrong sequence causing further movement.

We work exclusively with chartered structural engineers (CEng MIStructE) and carry £5 million public liability insurance. Every structural alteration gets a building control completion certificate — the document that proves the work was done correctly and that you'll need when you sell the property.

Floor/Roof Structure Repairs

Joist sistering (per joist): £200 – £400
Floor structure replacement (per room): £2,000 – £5,000
Roof structure repair: £3,000 – £12,000
Chimney breast removal + support: £1,500 – £3,500

RSJ / Steel Beam Installation

2-3 days on site for a standard single-beam installation. Day 1: set up propping, cut out wall section. Day 2: position and grout beam, install padstones. Day 3: remove props (if using rapid-set grout), make good around beam. Add 1-2 days for larger beams requiring crane access or multiple props. Pre-construction: 2-3 weeks for structural engineer calculations and building control submission.

Load-Bearing Wall Removal

3-5 days on site. Similar sequence to RSJ installation but with more demolition and making good. If the wall is a party wall, add 2 months minimum for the party wall process before you can start on site.

Underpinning

3-6 weeks on site. Traditional underpinning works in sequence — you can't excavate two adjacent sections simultaneously as this would undermine the foundation between them. Each 1-metre section takes roughly 2 days of work plus 7 days of curing. A 10-metre run therefore takes about 10-12 working days of active work spread over 5-6 weeks. Mini-piled underpinning: 2-3 weeks.

Subsidence Investigation & Repair

3-12 months total. Subsidence diagnosis often requires a period of crack monitoring (typically 12 months for insurance purposes, though this can sometimes be shortened). Once the cause is identified and the repair method agreed, the physical work takes 3-6 weeks for underpinning plus 2-4 weeks for superstructure repairs (crack stitching, replastering, redecoration).

Pre-Construction Lead Times

Structural engineer appointment and calculations: 1-3 weeks. Building control application: 2-4 weeks. Party wall process: 2-3 months. Total pre-construction: allow 4-6 weeks minimum for a standard job, 3-4 months if party walls are involved.

Never remove a wall without checking first. A partition wall that looks non-structural might be carrying loads from above — especially in older properties where walls have been altered over the decades. Even non-load-bearing stud walls sometimes support services (water tanks, soil stacks) that would be affected by removal. Always get a professional assessment.

Steel beams are heavier than you think. A 3-metre 203x133 UB weighs around 75kg. A 5-metre 305x165 UB weighs 200kg+. These can't be manoeuvred by two people in a standard domestic property. For beams above 4 metres, consider how it gets into the building — through the roof is sometimes easier than through the house. We've lifted beams through first-floor windows with a hiab crane more than once.

Padstones matter. The beam needs to bear on something that can distribute the load into the supporting wall. A concrete padstone (typically 450x225x100mm for domestic work) spreads the point load. Without one, the beam load crushes the brick or block beneath it. We've seen cracked walls and settled beams caused by missing padstones — it's a classic corner-cutting issue.

Document everything for resale. When you sell the property, your buyer's solicitor will ask for evidence of structural work. You need: structural engineer's calculations, building control completion certificate, party wall award (if applicable), and ideally photographs taken during construction showing the steelwork before it was covered up. We provide a full documentation pack at the end of every structural project.

Check your insurance for subsidence. If you suspect subsidence, contact your buildings insurer before instructing any work. Most policies cover subsidence repair (minus excess), but if you start work before the insurer has investigated, they may refuse to cover the cost. The insurer will typically appoint a loss adjuster, who will arrange monitoring, investigations, and eventually approve a repair scheme.

Chimney breast removal is structural work. Chimney breasts carry the weight of the stack above. If you remove the breast on the ground floor, you must support the breast on the floor above — either with a gallows bracket or a steel frame bolted to the party wall. If the breast on the floor above has also been removed and only the stack in the loft remains, that needs adequate support too. We see houses where chimney breasts have been removed without support — it's a serious structural defect that appears on surveys and kills property sales.