Steel beam calculations for building control: what is required

What building control actually checks

• Calculations from a competent person, in practice a structural engineer, showing the loads carried, the section's adequacy in strength and deflection, bearing and padstone design, and lateral restraint (gov.uk: building regulations approval).
• The work on site matching the calcs: the specified section, the specified padstones, proper bearing length, fire protection to the steel where required.
• Structural adequacy under Part A of the Building Regulations (Approved Document A). What will not satisfy that on its own: a span table printout, a steel supplier's suggestion, or an online checker's output, including ours.

Full plans or building notice

Two routes to the same duty. Full plans: calcs and drawings checked before work starts, slower to begin, but disputes surface on paper instead of on site. Building notice: no advance check, the inspector judges the work as it happens, and anything wrong gets rebuilt. Either way, regulation 16 of the Building Regulations 2010 says work must not start until at least two days have elapsed since the end of the day you gave notice of intention to start. For a single beam either works; builders who know their building control team often run a notice, cautious owners buy certainty with full plans. Either way there are inspections and, at the end, a completion certificate. Fees are set by each council or private building control approver and there is no national scale. The published 2026 domestic scales we read run from about £200 to £400 for a job of this kind (Bury charges £206 including VAT for structural alterations costing up to £2,000; Coventry charges £400 for minor work including removal of a load-bearing wall or formation of a new structural opening valued under £7,500). Some councils price the fee off the value of the works and come out higher, and regularisation costs more again, so check your own council's published scheme.

The completion certificate is the asset

Years later, nobody asks how big the beam was. They ask for the certificate: the buyer's conveyancer, the remortgage lender, occasionally the insurer after a claim. Work done without sign-off means a retrospective regularisation application, at a higher fee, with the council entitled to require opening up of finished work to see the steel and padstones, and an engineer paid to assess what should have been calculated up front. Indemnity insurance policies sold at sale cover legal risk, not the structure. The certificate costs a fee and a few inspections now; its absence costs a renegotiation later.

Not sure what your opening needs? Run the checker for the indicative range, then get the calcs, that is the document building control actually wants.