How to Price a Steel Beam Installation: Hire, Labour and Structural Costs

Quick Answer: A typical UK domestic steel beam installation — single beam, 3-4m span, knock-through between two rooms — prices at £2,800-£5,500 in regional England and £4,000-£8,000 in London. A goalpost frame (two beams meeting at a corner) runs £6,000-£12,000. Structural calculations (Eurocode 3, BS EN 1993) are required for any beam taking load above an opening greater than 1.2m.

Summary

Steel beam installation is one of the highest-leverage line items on a domestic refurb. The materials cost is modest — a typical 4m UB or UC beam is £350-£900 supplied — but the labour, propping, padstones, fire protection and making-good elevate the total to 4-10× the steel cost alone. Builders who quote based on the steel price get badly burnt.

The price also varies dramatically with site conditions. A clear-access knock-through with a 152 UC steel and 2m props is a 3-day job for two trades. A 6m bifold opening on a Victorian terrace with poor access, asbestos in the existing lath-and-plaster, and a needed needling exercise can take 2 weeks and cost three times as much.

This guide breaks down domestic steel installations across three common scenarios — a single internal knock-through, a rear opening for bifold doors, and a goalpost frame for a side return or rear extension corner — and gives the day rates, material costs, and engineer's fees needed to price each accurately.

Key Facts

• Structural engineer's calcs and drawings — £350-£900 for a single beam; £450-£1,200 for a goalpost; £800-£1,800 for a multi-beam scheme
• Beam supply — UB (Universal Beam) or UC (Universal Column) typical for domestic. Price by weight; current mill price ~£1,100-£1,500/tonne
• Typical 152 × 152 UC × 23kg/m × 4m — £140-£200 supplied
• Typical 203 × 102 UB × 23kg/m × 4m — £140-£220 supplied
• Typical 254 × 146 UB × 31kg/m × 4m — £200-£300 supplied
• Larger 305 × 165 UB × 40kg/m × 5m — £350-£550 supplied
• Padstones — concrete pre-cast or grouted brick; £35-£90 each, typically 2-4 per beam
• Acrow props + strongboys — hire £20-£35/prop/week; typically 4-8 props per job
• Bricklayer day rate — £200-£280 regional, £250-£350 London
• Builder/groundworker day rate — £200-£300 regional, £250-£350 London
• Specialist steelfixer/welder — £280-£400/day; £350-£500 London; rarely needed for domestic but used on engineered connections
• Steel delivery and offloading — £80-£200 for kerbside delivery; mechanical offload (HIAB) £150-£300 extra
• Fire protection — intumescent paint (60 minutes) £18-£40/m² applied; 2-layer plasterboard boxing £25-£45/m linear; vermiculite spray £40-£70/m²
• Building Control inspection — for beam installations; included in building notice fee or full plans approval
• Beams >100kg often need 4-person lift or genie lift — adds 0.5-1 day labour or £150-£300 equipment hire
• Lead time — 1-3 weeks from order on standard sections; longer for fabricated or galvanised
• Galvanising — £180-£350 for a typical beam, 1-2 week lead time
• Steelwork drawings for fabricator separately from structural calcs — £200-£500 if needed
• CE/UKCA mark required on structural steel since Construction Products Regulation transition; reputable fabricators apply automatically

Quick Reference Table

Detailed Guidance

The Single Internal Knock-Through

The bread-and-butter domestic steel job: opening up two reception rooms or a kitchen and dining room. The wall is masonry, load-bearing, and supports either floor joists or floor joists plus a roof.

Sequence:

1. Structural engineer surveys, prepares calcs and drawings. £350-£600. Confirm building over drains, services, and the depth of existing foundations to confirm bearing capacity.
2. Submit a building notice or full plans application. Full plans is safer for non-standard installations.
3. Strip the wall locally to expose substrate. Confirm masonry condition and check for lintels above existing openings (which need decommissioning or retention).
4. Erect Acrow props with strongboys both sides of the wall. Strongboys span 1-1.5m and pick up joists directly under the bearing line. Allow 4-6 props.
5. Break out brickwork above the planned beam line with hand tools or a stitch-cut saw (concrete cutter for clean line). Stay 50-100mm above final beam line to allow for slate or non-shrink grout packing.
6. Install padstones onto carefully prepared masonry beneath each bearing. Concrete padstones are standard (e.g. 215 × 215 × 215mm); grouted brick padstones are acceptable if engineer permits and bearing capacity is sufficient.
7. Lift beam into position. For a 4m, 100kg beam this is two people with one helper, or a genie lift. Pack the beam tight to the brickwork above using slate, hardwood wedges or non-shrink grout.
8. Build up brickwork at bearings, build in beam ends, pin the brickwork above with engineering brick or concrete to the slates.
9. Strike props after pinning has cured (typically 24-48 hours for grout, 7 days for full mortar strength).
10. Apply fire protection. Intumescent paint requires correct primer system and DFT (dry film thickness) to achieve 30 or 60 minute rating per the engineer's spec. Most domestic projects require 30 minutes minimum (Approved Document B, dwellinghouses).
11. Plasterboard boxing or plaster finish.

Day allocation: 3-5 days for a bricklayer and labourer = £1,200-£2,400 labour. Plus steel, padstones, props hire, fire protection, engineer's fee and making good. £2,800-£5,500 all-in regional.

The Wide Opening for Bifolds

5-6m openings need careful design — the beam is heavier (often 305 UB × 40 or larger), the deflection limit (L/360 typical) drives section size up, and the brick or block above the opening needs proper support throughout the install.

Specific cost drivers:

• Heavier beam needs HIAB delivery (£150-£300) and mechanical lifting (£200-£500 in genie or engine hoist)
• Padstones may be reinforced concrete or steel padstone plates (£60-£150 each)
• Existing lintel removal — often a stone or concrete lintel above the door — adds disposal cost
• Where the brick above is a single skin or weak rubble, needling may be required: timber needles pushed through holes in the wall above the line of the beam, supported on Acrow props each side. Adds 1-2 days
• Cavity work — most rear openings are cavity walls; the inner and outer skins need separate beams (or one cavity-spanning beam with a complex connection). Cavity arrangements add 30-50% to beam cost and complexity

Typical cost: £5,000-£8,000 regional, £7,000-£11,000 London for a 5m bifold opening.

The Goalpost — Side Return Corner

A goalpost is two beams meeting at a corner, with the corner loads passing through either a steel column or a heavily reinforced padstone. See side return extension pricing guide for the wider job context. Key cost points specific to the steelwork:

• Engineer designs the connection: typically a welded cleat with bolted padstone, or a bolted plate connection. Fabricated connections add £200-£600
• Site-welding of steel-to-steel is rare in domestic; most engineers detail bolted plates
• Corner column (often 152 × 152 SHS) £150-£300 supplied; padstone is reinforced concrete or steel plate
• Six padstones in total for a typical goalpost
• Temporary propping is heavier — corner takes load from two directions, props must be in both planes

Typical cost: £6,000-£12,000 fully fitted.

Beam Sizing — What the Engineer Looks At

The structural engineer considers:

• Load — dead load (masonry above, roof, joists), live load (BS EN 1991-1-1: 1.5 kN/m² typical for domestic floors), and any point loads
• Span — bearing-to-bearing distance
• Deflection limit — L/360 for dwellinghouses (Eurocode 3 with UK National Annex)
• Lateral torsional buckling — long unrestrained spans need deeper sections; restraint at top flange may be provided by joists or by a noggin detail
• Bearing capacity — at the support, the beam must distribute load over a padstone large enough for the masonry below to carry it (typically 215×215×215 concrete is suitable for residential)

A common rookie mistake: assuming a deeper beam is always safer. Beams cost ~£1,200/tonne, so unnecessarily deepening from 203 UB to 305 UB on a domestic span can add £200-£400 for no structural benefit and reduces headroom.

Fire Protection Choices

Approved Document B requires 30-minute fire resistance for structural steel in dwellinghouses. Three options:

Intumescent is preferred where the beam is exposed as a visual feature; boxing is cheaper but loses headroom.

Hire and Plant — Where Hidden Costs Live

Frequently Asked Questions

Can I install a steel beam without a structural engineer?

Not legally for any load-bearing application. Building Control will require calcs and drawings from a competent engineer (chartered or member of IStructE) before approving the installation. The Building Regulations 2010 require all structural work to demonstrate compliance with Part A. Buying off-the-shelf "lintel" steel for openings under 1.2m may be possible if a lintel table from a manufacturer covers the application, but anything bespoke needs an engineer.

How long does it take to install a steel beam?

A standard 3-4m knock-through is 3-5 days. A bifold opening is 5-8 days. A goalpost frame is 7-10 days. Add 1-3 weeks lead time for the steel itself to arrive. Fire protection is half a day to a full day on top.

What's the cheapest beam size I can use?

The smallest beam that satisfies deflection (L/360) and strength checks per Eurocode 3 with appropriate load factors. The engineer sizes it; you cannot substitute a smaller section without re-calculation. Builders sometimes try to "value-engineer" by reducing beam size — this is structurally non-compliant and uninsurable.

Do I need to galvanise a domestic steel beam?

No — internal beams in a dry environment do not need galvanising. Beams partially exposed to weather (e.g. corner posts on a glazed extension, beams over an open front porch) should be galvanised. Galvanising costs £180-£350 for a typical domestic beam and adds 1-2 weeks to lead time.

What about timber beams instead of steel?

For shorter spans (<3m) and lighter loads, glulam or LVL timber beams can be an alternative. They are typically 20-40% more expensive than steel for the same load, but the install is faster (no fire protection if encased in the wall structure), and the timber appearance is preferred in some restoration projects. Engineer-specified only.

Regulations & Standards

• Building Regulations 2010 — Part A (Structure), Part B (Fire safety, including 30-minute structural fire resistance for dwellinghouses)

• BS EN 1990:2002+A1:2005 Eurocode — Basis of structural design

• BS EN 1991-1-1:2002+A1:2014 Eurocode 1 — Actions on structures (loadings)

• BS EN 1993-1-1:2005+A1:2014 Eurocode 3 — Design of steel structures

• BS EN 1993-1-2:2005 Eurocode 3 part 1-2 — Structural fire design

• BS EN 1090 — Execution of steel and aluminium structures; CE/UKCA marking

• BS EN ISO 12944 — Paints and varnishes, corrosion protection by paint systems

• BS 476-20:1987 / BS EN 13501-2:2016 — Fire resistance testing of structural elements

• CDM 2015 — Construction Design and Management Regulations; lifting operations require lift plan for items above prescribed loads

• LOLER 1998 — Lifting Operations and Lifting Equipment Regulations

• PUWER 1998 — Provision and Use of Work Equipment Regulations

• Approved Document A — Structure — Building Regulations

• Approved Document B — Fire safety — Building Regulations

• Steel Construction Institute — domestic steel guidance — sizing tables and design notes

• British Constructional Steelwork Association — fabrication and erection standards

• Institution of Structural Engineers — find a chartered engineer

• LABC — Local Authority Building Control — Building Control inspection guidance

• single storey extension pricing guide — extension pricing including knock-throughs

• side return extension pricing guide — goalpost framing in side returns

• loft conversion pricing guide — loft beam installations

• party wall act notice — Party Wall notice for beam bearings on party walls

• building regulations overview — Building Regs framework