Detailed answers to the questions clients, architects and contractors ask most often — written in plain English by a Chartered Structural Engineer, and available as branded PDF and Word guides you can keep, print or share with your project team.
You need a structural engineer whenever the strength, stability or load path of a building is affected. In practice that means removing or altering a load-bearing wall, forming a new opening, building an extension or loft conversion, adding significant new loads, underpinning, or investigating cracking and movement. Building control will normally expect supporting calculations for that work, and an architect's drawings alone do not provide them. If you are unsure, a short conversation is usually enough to establish whether engineering input is required and, if so, how much.
A structural engineer works out how a building carries load safely — down through beams, columns, walls and foundations into the ground — and designs the members needed to do it. The work covers load assessment, analysis, member and connection design, stability, foundations and buildability, and it is recorded in calculations and drawings. Engineers also inspect existing buildings, diagnose cracking and movement, appraise structures for change of use, and design temporary works. On most projects the engineer works alongside the architect and contractor rather than replacing either.
Most domestic structural work is quoted as a fixed fee once the scope is clear, because that is what clients find easiest to budget. The fee reflects the number of structural elements to be designed, whether a site visit is needed, the quality of the information available and how much revision is likely. Small single-beam schemes sit at the lower end; multi-element extensions, loft conversions with new floor structures, or projects with unknown existing construction sit higher. Larger commercial and industrial commissions are usually staged against project milestones. A precise figure always follows a clear brief.
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.
Almost always, yes — provided the load it carries is picked up by a correctly designed beam and taken safely down to adequate support and foundations. The engineering work is to establish what the wall carries, size a beam for strength and deflection, check the bearings and padstones at each end, and confirm the supporting masonry or columns below can take the concentrated load. Temporary support must be designed and installed before demolition. Building control approval is required, and the finished opening usually needs fire protection to the new beam.
Building Regulations approval is required for most building work that affects structure, fire safety, insulation, drainage or ventilation. Structurally, that includes extensions, loft conversions, new openings in load-bearing walls, new beams and columns, underpinning and significant repairs. Approval is obtained through your local authority building control or an approved inspector, either by full plans submission or a building notice. Structural calculations form part of the evidence. A completion certificate matters later: purchasers' solicitors routinely ask for it, and its absence can delay or reduce a sale.
Planning permission governs what a building looks like and how it affects its surroundings — size, siting, appearance, use, overlooking and impact on neighbours. Building Regulations govern how it is built — structure, fire, insulation, drainage, ventilation and safety. A project can need one, both or neither. Permitted development rights may remove the need for planning permission but never remove the need for Building Regulations approval. Structural calculations belong to the Building Regulations process; planning officers do not assess them.
A structural survey — more precisely a structural appraisal — is worth commissioning when there is visible cracking or movement, when a homebuyer report has recommended further investigation, when a building is being bought or altered and its construction is unknown, or when a change of use will increase loading. It differs from a valuation or homebuyer survey: an engineer looks specifically at load paths, structural condition, causes of movement and what remedial work, if any, is justified. The output is a written appraisal with a clear conclusion and recommendations.
The engineer arrives with the background you have supplied, walks the building externally and internally, and examines the structure that can be seen — walls, floors, roof, lintels, beams, and any visible cracking or distortion. Cracks are measured and photographed, floor levels and verticality may be checked, and the likely load paths are established. Where the cause is not clear from a visual inspection, monitoring, opening-up or specialist testing may be recommended. A written report follows, setting out findings, likely causes, structural significance and recommended action.
The more accurate the information, the faster and cheaper the engineering. Most useful are dimensioned architectural drawings of the existing and proposed layouts, photographs of the areas affected, an indication of floor joist directions, and a short written description of what you want to achieve. Where they exist, previous reports, ground investigation data, planning documents and drainage information all help. If you have none of this, say so — an engineer can advise what is genuinely needed rather than requiring a full set before starting.
For a straightforward domestic scheme with good information — a single beam or a simple extension — calculations are typically issued within a few working days of appointment. Multi-element projects, loft conversions with new floor structures, or schemes requiring a site visit generally take one to two weeks. Commercial and industrial work is programmed against project milestones. The critical variable is rarely the calculation itself but the completeness of the information: waiting for drawings, joist directions or ground data is what usually extends a programme.
A meaningful quotation needs enough information to identify the structural scope: what the building is, what is changing, roughly how many structural elements are involved, whether a site visit is needed and when the information is required. Drawings and photographs answer most of that in one step. Where drawings do not yet exist, a clear written description and a few photographs are usually sufficient for a fee range, with the figure confirmed once the layout is fixed. Quotations state deliverables, assumptions, exclusions and programme.
Yes — that is the most common arrangement. BES works alongside architects from feasibility through to construction, providing structural input as the design develops so that spans, beam depths, column positions and foundation constraints are resolved before the scheme is fixed. Early coordination avoids the familiar problem of a beautiful layout that requires an unreasonably deep beam or a column in the middle of a kitchen. BES can be appointed directly by the client or work under the architect's coordination, whichever suits the project.
Yes. Many projects are contractor-led, particularly domestic alterations where the builder is engaged before any designer. BES can be appointed by the contractor or by the client with the contractor as the day-to-day point of contact. Working directly with the builder tends to produce more buildable details: sensible beam depths, achievable bearing details, realistic temporary works and sequencing that suits the site. BES also responds to queries during construction, including the unexpected conditions that appear once plaster and floorboards come up.
Often, yes. Photovoltaic panels add permanent load to a roof that was designed without them, and building control frequently ask for confirmation that the existing rafters, purlins or trusses can carry it. On a typical modern trussed roof in good condition the additional load is modest and a straightforward check is enough. Older roofs, long spans, slender rafters, altered or repaired structures, and in-roof systems that remove tiling all warrant closer assessment. Wind uplift on the panels and the adequacy of their fixings also need consideration.
Most cracking has an ordinary explanation. Thermal and moisture movement, drying shrinkage of new plaster or blockwork, and long-term settlement account for the majority of cracks in domestic buildings. Structurally significant cracking is less common and tends to be associated with foundation movement, subsidence, heave, overloading, failed or missing lintels, corroded wall ties or removal of structure without adequate support. Location, orientation, width, whether the crack passes through masonry units, and whether it is changing over time all help identify the cause.
Usually not immediately, but cracking should be understood rather than ignored. Fine hairline cracking in plaster is normally cosmetic. Cracks that are wide, diagonal, stepped, growing, or accompanied by sticking doors, sloping floors or bulging walls deserve prompt assessment. Anything suggesting instability — a leaning wall, a sagging beam, spalling concrete exposing corroded reinforcement, or sudden movement — should be treated as urgent and the area kept clear until an engineer has advised. Photographing and dating cracks is the single most useful thing an owner can do.
Yes. Industrial and process structures form a substantial part of the studio's background, including manufacturing facilities, energy plants, quarry and materials-handling structures and heavy process installations. Typical commissions include condition surveys of portal frames and steel-framed warehouses, assessment of corrosion and impact damage, appraisal of structures for new plant or increased loading, crane and gantry assessments, and review of access, walkway and platform structures. Inspections are planned around operational constraints so that production is disrupted as little as possible.
Temporary works are the structures that hold a building up while permanent work is carried out — propping, needling, shoring, façade retention, excavation support, formwork and falsework. They are designed structures in their own right and carry real risk: many construction incidents occur during temporary conditions rather than in the finished building. Design covers the loads at each stage, the capacity of the props and needles, the ground or floor they bear onto, stability, and the sequence in which everything is installed and removed.
Connection design determines how steel members are joined — the plates, bolts and welds that transfer forces from one member to another. Members can be perfectly sized and the frame still fail at its joints, so connections are designed for the actual forces they carry: shear, moment, axial tension or compression, and often a combination. Typical connections include fin plates, flexible end plates, moment end plates, splices, base plates and bracing gussets. Design also considers fabrication, fit-up, erection access, tolerance and corrosion protection.
A structural appraisal is an engineering assessment of an existing structure: what it is made of, what condition it is in, what it can safely carry, and whether it suits its current or proposed use. It goes beyond a visual inspection by combining observation with calculation — establishing member sizes, estimating material strengths, checking capacity against present and future loading, and identifying where strengthening is needed. Appraisals support change of use, added plant, new floors, refurbishment, insurance and purchase decisions, and remedial design following damage.
Yes. Independent checking and design review is a distinct service in which BES examines another engineer's design against the brief, the loading, the relevant codes and buildability, and reports on its adequacy. Checks range from a proportionate review of assumptions and critical members to a full independent recalculation. Clients commission checks for high-consequence structures, as a condition of insurance or funding, where a design has been inherited mid-project, or simply for confidence before construction begins. The scope and depth of check are agreed in writing beforehand.
Yes. Advanced manufacturing facilities combine ordinary building structure with demanding process requirements: heavy and often moving equipment loads, tight deflection and vibration criteria, service-dense ceiling zones, clean-room interfaces, phased installation and the need to keep production running during alterations. BES has substantial experience of process and manufacturing structures, including steel-framed production buildings, equipment support structures, pipe racks, platforms and plinths, and the structural coordination required between process, mechanical and building disciplines.
Yes. Data centre structures are dominated by plant: heavy uninterruptible power supplies and battery rooms, generators, chillers and cooling plant, cable containment and raised access floors, all supported within a structure that must accommodate future load growth and remain serviceable during upgrades. BES can provide structural design and appraisal for new-build and retrofit projects, including assessment of existing buildings for conversion, generator and plant support structures, roof plant loading, and structural coordination with mechanical and electrical layouts.
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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.
