Structural Calculations

Structural calculations for building control approval

Building control will not approve structural work on a builder's say-so — they want structural calculations from an engineer. The panel's engineers produce building-control-ready calculation packs for the jobs UK homes actually generate, at fixed fees and on builder-friendly timescales.

Calculations provided

• Steel beam and lintel sizing — RSJs for wall removals, openings and knock-throughs, with padstone and bearing design.
• Loft conversion packs — floor beams, rafter and purlin checks, dormer framing and staircase trimming.
• Extension calculations — foundations, roof structure, ridge and valley beams, bi-fold and box-frame openings (see the extension structural design service).
• Chimney breast removal support — gallows brackets where permissible or beam solutions where not.
• Remedial works — calculations backing the repairs a structural report recommends.

What you receive

A calculation pack in the format building control expects: member sizing to the relevant standards, load paths, bearing and padstone details, connection notes, and sketches your builder can work from. Your engineer liaises directly with your building control officer if queries arise — that back-and-forth is included, not extra.

Why building control asks for calculations

Structural alterations must satisfy the Building Regulations' structural requirements, and neither a local authority building control team nor a registered building control approver will take adequacy on trust. Whether you apply through full plans (calculations checked before work starts — the safer route for anything structural) or a building notice (checked as the work proceeds), the checking officer needs to see that the loads have been followed from roof to foundation and that every new member is justified. A builder's assurance that “that steel's plenty” is what gets sites held up; calculations in the expected format are what gets them approved.

What your engineer needs from you

Usually less than people expect. For a beam or wall removal: photographs of the wall from both sides, a rough floor plan with dimensions, and a note of what sits above — rooms, roof, another wall. For lofts and extensions: your architect's existing and proposed drawings. Most domestic calculations are produced from this information without a site visit; where an inspection is genuinely needed — concealed structure, unusual construction, movement in the existing fabric — the quote says so up front rather than surprising you later.

What “building-control-ready” means

A pack a checking engineer can approve without re-deriving it: design to the current British Standards and Eurocodes, stated loading assumptions, and members justified in sequence so the load path is auditable from roof to foundation — with the member schedule keyed to a marked-up plan so the builder knows which beam goes where. A bare beam size with no supporting logic generates rounds of queries and a site on hold; a pack in the expected format goes through. That, as much as the arithmetic, is what you are buying.

Structural calculations cost

Pricing follows scope, and scope is countable: how many members need justifying, how many storeys the loads pass through, and whether the existing structure must be checked as well as the new. A single beam for a doorway sits at the bottom of the range; a full loft conversion or double-storey extension pack involves a dozen or more member designs plus foundation checks. Every job is quoted fixed from your drawings or photos before you commit — see our structural engineer cost guide for typical market figures, and the wider structural engineering service for everything that sits around a calculation.

Timescales and urgent jobs

Standard turnaround is 3–5 working days from instruction, and the clock matters differently depending on who is waiting: a builder priced and booked needs the steel schedule before demolition starts; a full-plans application wants calculations submitted with the drawings, weeks before start on site; a regularisation application for work already done needs whatever the officer asks for, quickly. Tell us which situation you are in — urgent turnarounds can usually be accommodated, and it is easier to hit a real deadline we know about. If you are still at the “can this wall even come out?” stage, start with a structural inspection — it is cheaper to ask before the skip arrives.

Send your drawings — get a fixed quote today →