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

Quick Answer: A typical residential RSJ installation in 2026 prices between £1,800 and £6,500 fitted including beam supply, padstones, structural calculations, fire protection and making good. The most common UK job — a single 3–5 m universal beam over an internal load-bearing wall — runs £2,400–£4,200. Larger goalpost frames and multi-beam installations price from £6,000 to £18,000. Pricing is driven by beam tonnage (£1,800–£2,400 per tonne fabricated), span length, access route to the installation point, and whether temporary propping or hired Acrows are needed.

Summary

Steel beam pricing splits into five distinct line items: the beam itself (raw steel + fabrication + delivery), the structural design and calculations, the temporary works (propping, Acrows, scaffold), the labour to install, and the making-good (padstones, fire protection, plaster reinstatement). Quoting one global figure without these line items is the most common reason steel beam quotes look too cheap to be real.

For tradespeople, the rule of thumb is that the steel itself is roughly 25–35% of the total fitted price. A £2,200 steel beam installed costs £6,000–£8,000 once everything is added. The mistake of quoting the steel cost alone — assuming the homeowner understood the rest was extra — is responsible for a large share of disputes on residential structural work.

The two structural calculations that most affect cost are the beam section (depth × flange × web thickness) and the bearing detail. A 203 × 133 UB 25 kg/m beam costs about half what a 254 × 146 UB 37 kg/m beam costs in raw steel. The bearing detail — whether the beam sits on padstones, on engineering brick padstones, on a steel column, or is welded into a goalpost — determines labour time. A simple drop-in over masonry padstones is half a day's work; a welded goalpost frame is two to three days plus prep.

Key Facts

Quick Reference Table

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Job type Beam typical Total fitted price 2026 Time on site
Small internal beam (single span 2–3 m) 152 × 89 UB 16 kg/m £1,800–£2,800 1 day
Standard knock-through (4–5 m) 203 × 133 UB 25–30 kg/m £2,400–£4,200 1–2 days
Large opening (5–6 m) 254 × 146 UB 31–43 kg/m £3,500–£5,500 2 days
Side return goalpost (1 horizontal + 2 verticals) 203 × 133 UB + 152 × 152 UC £6,000–£14,000 2–3 days
Lateral steel frame for full rear opening Multiple 254/305 UB sections £8,000–£18,000+ 3–5 days
Two-storey loft conversion floor steels (3–5 beams) 203 × 133 UB or TJI hybrid £4,500–£9,500 fitted 3–5 days

Detailed Guidance

Sizing the Beam — Why You Cannot Quote Without Calculations

The beam section is determined by the structural engineer based on span, load above (number of floors, roof, load combinations), bearing conditions, and deflection limits. Two engineers presented with the same opening can specify different beams depending on which load case governs. Quoting from the homeowner's "I think it's about a 4-metre opening" is unsafe — the beam may end up materially larger and the price calculated on guesswork.

For a typical UK terrace knock-through between front parlour and rear reception:

The price-per-tonne method works reliably: take the beam weight × length × £1,900–£2,300 + £200 fabrication + £150 delivery. A 4 m beam at 25 kg/m = 100 kg = 0.1 tonne × £2,000 ≈ £200 raw + fabrication + delivery = £550–£700 supply only.

The Bearing Detail Drives Half the Labour

How the beam sits on its end supports is the second-biggest cost variable.

Concrete padstones bedded on existing brickwork — simplest and cheapest. The bricklayer cuts a pocket in the wall, beds the padstone on cement mortar, allows to set, drops the beam onto the padstones, packs to level. Half-day per end.

Engineering brick padstones built up to receive the beam — used where the existing masonry is weak or where the beam soffit is at a level requiring a pier. Class B engineering bricks (95 N/mm² compressive strength), 4–6 courses high. Half to full day per end.

Welded plate to a steel column (goalpost) — used in side returns and full rear elevations. The vertical posts are erected first onto pad foundations, the horizontal beam dropped onto fabricated cleats and bolted through. A skilled steel erector is normally needed; a general builder cannot weld site-built connections without certification. Full day per connection.

Beam-to-beam connection (in a frame) — used where multiple beams meet to form a transfer structure. Almost always pre-fabricated off-site to engineer's design, dropped in as a single unit. £1,500–£3,500 connection labour element on top of beam supply.

Temporary Works — Often Underpriced

Before the beam goes in, the load above must be supported. Acrow props (universal steel telescopic props), Strongboy attachments, or proprietary needling beams transfer the load to floor or ground.

Standard internal load-bearing wall removal — 4–6 Acrow props above the line of work, plus needling beams (timber or steel) passed through the wall above the new beam line. Hire cost £80–£200 for the duration.

External wall in a side return — needs needling above and Strongboys onto the brickwork below to support the brickwork while the beam goes in. Hire cost £150–£400.

Two-storey lateral steel — substantial temporary works, including scaffold inside and out. £600–£1,800 in temporary works alone.

The risk of skimping on temporary works is the wall above settling or cracking before the beam is permanently propped. The cost of putting that right is many multiples of the temporary works hire — never compromise on this line.

Fire Protection — The Building Control Trigger

Approved Document B requires structural steel in residential occupancies to achieve 30 minutes' fire resistance for most 2-storey homes; 60 minutes for 3-storey or where the steel supports an escape route; 90 minutes in some HMO and flat conversion contexts.

Intumescent paint — water-based or solvent two-coat system applied 0.5–2 mm dry film thickness to the bare steel. £15–£35 per linear metre of beam at 30-min; £20–£50 at 60-min. Suitable where the beam is exposed; cheapest "in-place" protection.

Plasterboard boxing — 12.5 mm Type F board for 30-min, 15 mm Type F or double 12.5 mm for 60-min. Adds visual depth to the beam soffit. £20–£40 per linear metre installed.

Vermiculite spray — used where appearance does not matter; £30–£70 per linear metre; requires specialist applicator.

The fire protection certificate (intumescent paint thickness measurements or boxing detail) must be available for the Building Control completion certificate.

Building Control and CDM

Steel beam installations in dwellings always require Building Regulations approval. Two routes:

CDM 2015 applies to almost all structural alteration work. The homeowner is the client and has duties under Regulation 4. The principal contractor (or domestic client builder if single-contractor) handles the construction phase plan and notification (F10 if over 500 person-days or 30 working days).

Making Good — The Quietly Expensive Bit

Once the beam is in and fire-protected, plaster, decoration, flooring and electrics need to be reinstated:

Total making good for a typical knock-through: £1,200–£3,500 in addition to the beam fitting cost.

Frequently Asked Questions

Can I install a steel beam without Building Control?

No. Removing or altering a load-bearing wall is notifiable structural work under the Building Regulations. Doing so without Building Control approval makes the work uncertified, which causes problems on resale and invalidates buildings insurance for any related damage. Even for an "open the wall a bit" job, the Building Notice route is mandatory.

Why do steel beam quotes vary so much?

Five reasons: (1) different engineers may specify different beam sections; (2) the bearing detail (simple padstone vs welded goalpost) changes labour by a factor of 2–3; (3) fire protection method (intumescent paint vs plasterboard) changes cost by 30–50%; (4) access to the installation point — a ground-floor knock-through is half the labour of a first-floor steel; (5) some quotes include making good, others don't.

Do I need a chartered structural engineer?

For Building Control approval in England, the engineer must be competent. In practice this means CEng MIStructE, or a chartered chartered with structural experience, or a member of a Competent Person Scheme. A graduate engineer working under a chartered engineer's PII is acceptable.

How long does a typical knock-through take?

Site time: 1–2 days for the steel installation itself. Add 3–5 days for plaster drying before decorating; 1–2 weeks elapsed for the full job including making good. The beam is typically dropped in on day 1 morning, with packing and bedding complete by day 1 evening; props removed day 2 once mortar has set.

Can the steel beam be galvanised instead of intumescent painted?

Galvanising provides corrosion protection but not fire protection — it does not contribute to fire resistance rating. For internal beams in residential use, intumescent paint or boxing is needed regardless of galvanising. Galvanising is mainly relevant for external beams (e.g. canopies, garden room steels) where the beam is exposed to weather.

Regulations & Standards