The short answer
Structural calculations should be produced by a qualified structural or civil engineer who can design to the Eurocodes and provide a signed, stamped calc pack. In practice this means a Chartered Structural Engineer (CEng MIStructE) through the Institution of Structural Engineers, a Chartered Civil Engineer (CEng MICE) through the Institution of Civil Engineers, or an Incorporated Engineer (IEng) competent in the relevant work. There is no single licence the law demands, but Building Control must be satisfied the person is competent, and calculations from a recognised chartered or incorporated engineer are accepted without dispute. Your builder generally cannot provide acceptable calculations unless they hold the relevant engineering competence — sizing a structural beam by eye or copying one from another job is exactly what Building Control will challenge.
"Can't the builder just work out the beam?" is a common question. Here is who is actually qualified to produce calculations Building Control will accept.
Who is qualified
- Chartered Structural Eng.CEng MIStructE (IStructE)
- Chartered Civil Eng.CEng MICE (ICE)
- Incorporated Eng.IEng, if competent in the work
- Builder aloneUsually not accepted
- Acceptance testBuilding Control satisfied of competence
The recognised qualifications
UK structural engineering competence is signalled by professional membership of one of the recognised institutions. These titles tell Building Control, and you, that the person has the training and assessed experience to design structure safely.
- Chartered Structural Engineer (CEng MIStructE): a member of the Institution of Structural Engineers who has passed its rigorous Chartered Membership Examination — the specialist route for building structure.
- Chartered Civil Engineer (CEng MICE): a member of the Institution of Civil Engineers; many civil engineers are fully competent in building structures.
- Incorporated Engineer (IEng): a recognised professional grade that can be entirely competent for domestic and routine structural work.
- Associate / technician grades: some work is produced by experienced technicians under the supervision of a chartered engineer who takes responsibility for it.
The chartered titles are protected and awarded only after assessment, which is why calculations carrying them are rarely questioned. The Engineering Council holds the national register behind these titles, and the IStructE and ICE assess and award them — so when you see CEng MIStructE or CEng MICE after a name, it reflects a documented level of competence rather than a self-declared one. For domestic work the key point is that the person putting their name to the calculations is professionally accountable for them: if a design is later found wanting, a chartered or incorporated engineer carries the responsibility and, normally, the professional indemnity insurance to back it.
What Building Control actually requires
The law does not name a single qualification. Part A of the Building Regulations requires the structure to be shown to be adequate, and Building Control must be satisfied of the competence of whoever produced the design. In practice they accept calculations from chartered and incorporated engineers as a matter of course.
| Who | Typically accepted? | Notes |
|---|---|---|
| Chartered structural engineer | Yes | Specialist for buildings |
| Chartered civil engineer | Yes | If competent in the work |
| Incorporated engineer | Usually | For routine domestic work |
| Builder (no eng. qual.) | No | Sizing by eye is challenged |
| Beam supplier's design | Sometimes | For their own product only |
Indicative only; the local Building Control body makes the final judgement. Sources: IStructE; ICE; LABC guidance.
Why your builder usually cannot do it
A good builder knows roughly what beam a job needs and will often have a size in mind, but that is experience, not a calculation. For Building Control to accept it, the size has to be justified by a load take-down and the bending, shear and deflection checks set out on paper to the Eurocodes.
How to find and check the right person
Finding a competent engineer is straightforward, and a few checks confirm you have the right one for the job. Both main institutions let you verify membership, which is the single most useful check you can make.
- Use the institution directories: the IStructE and ICE both publish ways to find members and confirm someone holds the title they claim. A genuine CEng MIStructE or CEng MICE is on the register.
- Check professional indemnity insurance: a practising engineer should carry PI cover, which protects you if a design error is later found. Ask to see it for anything beyond a trivial job.
- Match the engineer to the work: a domestic beam or loft is routine for most structural engineers; a basement, a complex remodel or temporary works needs someone who does that work regularly.
- Confirm the deliverable: you want a signed, dated calc pack that states the member sizes, bearings and the loads assumed, and that Building Control will accept — not a verbal opinion on a beam size.
- Be cautious with "design and build" beam suppliers: some steel suppliers offer a design service, but it usually covers only their own product and may not address the bearings, padstones or the rest of the load path. Building Control may still want an independent engineer's pack.
For most homeowners the practical answer is to instruct a local structural engineering practice early, ideally alongside the architect, so the beam positions and likely sizes are allowed for in the design. The person who produces the calculations takes professional responsibility for them, which is precisely why a qualified engineer — not a builder working from memory — is the right choice for anything that carries real load.
Frequently asked questions
Can an architect do structural calculations?
Not usually. Architects design the layout and appearance but are not generally trained to produce structural calculations to the Eurocodes. Most architects work alongside a structural engineer who does the calcs. Some practices have an in-house engineer.
Do I have to use a chartered engineer?
Not strictly — the law requires competence, not a specific title. But calculations from a chartered (CEng MIStructE or MICE) or incorporated engineer are accepted by Building Control without dispute, which is why most homeowners use one for beams and lofts.
Can a steel supplier provide the calculations?
Some suppliers offer a design service, but it typically covers only their own beam and not the wider load path, bearings or padstones. Building Control may still want an independent engineer's pack, so check before relying on a supplier's figures alone.
Sources & further reading
- The Institution of Structural Engineers — membership and finding an engineer
- Institution of Civil Engineers — about chartered engineers
- LABC — competence and Building Control
Figures on this page are typical UK ranges drawn from published sources and depend on your specific project. They are guidance, not a quotation.