Short answer
Structural calculations are needed whenever building control, a warranty provider or a client requires evidence that a structure is adequate. That normally applies to any new or altered load-bearing element: beams over new openings, columns, lintels above a certain span, new floor or roof structures, foundations, retaining walls and underpinning. Calculations demonstrate compliance with Building Regulations Part A and give the contractor the sizes and details needed to build. They are also frequently requested during conveyancing, where past alterations were carried out without documentation.
Branded guidance note, prepared for project records and circulation to your team.
Typical triggers
- Any new beam, column or lintel carrying floor, roof or wall load
- New or modified foundations, including underpinning
- Loft conversions where new floor joists or dormer structures are formed
- Retaining walls and basement structures
- Change of use that increases imposed floor loading
What a calculation package contains
- Loading assumptions and load take-down
- Design of each structural element against the relevant Eurocode
- Bearing, connection and padstone details
- Deflection and serviceability checks
- Sketches or drawings tying the calculations to the building
How BES is typically involved
- BES prepares the calculation package to a standard building control accept without repeated queries.
- Preliminary sizing can be provided early so the contractor can price before the full package is issued.
- Where an inspector raises a comment, BES responds directly.
Typical process
- 01Confirm the structural scheme and loads
- 02Preliminary member sizing
- 03Detailed design and serviceability checks
- 04Issue of calculations and sketches
- 05Building control comment response
Common misconceptions
Commonly assumed
“Standard span tables are always enough.”
In practice
Tables cover simple, regular cases only. Point loads, trimmed openings and irregular spans fall outside them.
Commonly assumed
“Calculations can be produced after the work is built.”
In practice
They can, but retrospective justification is harder and occasionally concludes the built element is inadequate.
Related tools and services
Resource Centre tool
Preliminary Beam Sizing
Explore an indicative steel beam size using bending, lateral-torsional buckling, shear and deflection criteria.
Open Beam Sizing Tool →Resource Centre tool
Beam Deflection Check
Estimate the elastic deflection of a simply supported beam under a uniformly distributed load and compare it with a selected span-based deflection limit.
Open Deflection Tool →Resource Centre tool
Steel Section Capacity Checker
Verify a steel section you have already selected — bending, shear, deflection, web bearing, web crushing and approximate lateral-torsional buckling, with utilisation and reserve capacity.
Open Capacity Checker →Related questions
Discuss your project
General guidance only goes so far. Describe your building and what you are planning, and you will receive project-specific advice from a Chartered Structural Engineer.
Discuss Your Project →Next scheduled review August 2027
Disclaimer
Indicative result only. The calculation depends on the assumptions and information entered and does not constitute structural design or professional advice. Do not use the result for construction, procurement, Building Regulations submissions or safety-critical decisions. All results must be independently verified by a suitably qualified structural engineer before being used for design, construction or regulatory purposes. Bebbington Engineering Studio Ltd accepts no responsibility for reliance placed on unverified results.