Coordinated structural calculations for London extensions, loft conversions, basements and wall-removals. Fixed fee from £495, IStructE-chartered engineer reviewed, fully Building Regulations Part A compliant.
Every structural calculation pack we deliver is designed to be handed straight to building control, your contractor and your steel fabricator. Signed and stamped by a chartered structural engineer, with member sizing, connection details and a full set of structural drawings.
Universal Beam, Universal Column and RSJ section sizing to Eurocode 3 (EN 1993). Capacity verified against the SCI Blue Book (P363) for bending, shear, deflection and lateral-torsional buckling. Includes bearing pad design, padstones, restraint and connection schedule.
Strip, pad and trench-fill foundation design to Eurocode 7 (EN 1997). Bearing pressure calculations with London-clay-specific values, NHBC Chapter 4.2 tree zone adjustments where relevant, plus drainage diversion notes. Suitable for new builds, rear extensions and side returns.
Ridge beam, purlin, trimmer and floor joist sizing for hip-to-gable, mansard, dormer and L-shaped loft conversions. Existing ceiling joist capacity check, party-wall flank loading, dormer cheek framing and Velux trimmer details — everything building control will ask for.
Opening-up calcs for knock-throughs, kitchen-diner reconfigurations and corner openings — including the trickier scenarios involving twin steels, plated beams, goalpost frames or new columns on padstones. Temporary works guidance included for the contractor.
Reinforced-concrete retaining wall design to Eurocode 2 (EN 1992), traditional underpinning sequence, lateral earth pressure checks with London clay parameters, party-wall protection scheme and temporary propping schedule. Coordinated with a CDM-aware temporary works engineer.
General arrangement plan, section through new structure, beam-and-column schedule, padstone details and connection sketches. Issued as PDF and CAD (DWG) at A2 / A3, layered to BS 1192. Ready to be issued direct to your steel fabricator for shop drawings.
The right calculation pack depends on what you're altering, how many elements need sizing, and whether ground works or temporary propping are involved. Below is the plain-English matrix, with the typical fixed fee for each. Every option includes IStructE chartered sign-off.
One steel over a single opening — classic kitchen knock-through, side-return doorway or chimney removal. Includes beam sizing, padstone design, load takedown and a single-page general arrangement detail. Building Regs Part A compliant.
Ridge or purlin beam, floor-joist sizing, dormer trimmers, party-wall flank loading and connection schedule. The standard pack for a London Victorian or Edwardian terrace dormer or hip-to-gable conversion. Most common loft option.
Goalpost frame across rear, ridge / flat-roof structure, new strip foundations, beam-to-column connections and lintel schedule for a standard single-storey rear or side-return extension. Coordinated with the architectural and Building Regs drawings.
Full underpinning sequence, reinforced concrete retaining wall to Eurocode 2, ground-floor transfer slab, temporary propping schedule and party-wall protection scheme. Includes IStructE sign-off plus a CDM-aware temporary works statement.
Twin steels with a corner column, new strip foundations, transfer beam at first floor and connection details for a wraparound or double-storey side-return. Multi-element packs requiring careful load-path coordination across new and existing structure.
A standard single-beam or loft conversion structural pack completes in five working days from receipt of your measured survey and architectural drawings. Basement or multi-element packs run to 7–10 days. A 48-hour express service is available for urgent building control deadlines.
Day 1 — architectural plans, measured survey and site photographs uploaded to the portal.
Day 2 — engineer derives roof, floor and wall loads and sizes preliminary members.
Days 3–4 — Eurocode (BS EN 1990–1999) calculations and structural drawings drafted.
Day 5 — chartered structural engineer peer-checks and signs the pack.
Day 5 — PDF calc pack + DWG structural drawings emailed, ready for building control.
Anonymised pages from a recent loft-conversion structural pack delivered to a Wandsworth Victorian terrace. Includes the general arrangement plan, the ridge-beam calculation sheet, a typical padstone bearing detail and the issued structural drawing — everything needed for building control sign-off and steel fabricator pricing.
Want the full PDF pack? Start a free quote and we’ll email a redacted sample matching your project type.
Single beam, foundations, basic loft trimmer or single wall removal.
Full extension or loft package — calcs + structural drawings.
Underpinning, basement RC walls, multi-element transfer structures.
Every project is different. Call +44 7592 201 353 for a five-minute chat with a chartered engineer.
Get structural quote →Yes. Building Regulations Part A (Structure) requires verified calculations any time you alter the load path of a building — including removing a single load-bearing wall, inserting a single steel beam, cutting a new opening or notching trimmer joists for a loft conversion. Building control will request the calc pack before issuing a completion certificate.
All calculations are prepared and signed off by a chartered structural engineer registered with the Institution of Structural Engineers (IStructE) or the Institution of Civil Engineers (ICE). The signed PE statement, calculations and supporting structural drawings are issued together as a single deliverable pack accepted by every London borough building control body and approved inspector.
All new calculations are produced to Eurocode (EN 1990–EN 1999, with UK National Annexes) which has been the mandatory standard since 2010. We still occasionally issue retrospective verifications to BS 5950 / BS 8110 where a project pre-dates the changeover or a council surveyor specifically requests it. Steel sizing is checked against the Blue Book (SCI P363) for capacity tables.
Rejection is rare on our packs — typically under 2% of submissions — because every calculation is internally peer-checked, load takedowns are cross-referenced against the architectural drawings, and member sizing is checked against the SCI capacity tables before issue. If a council surveyor does raise a query, we re-issue with no extra fee.
For complex, heritage or basement projects, yes — a site visit is included in the fee to confirm existing wall construction, foundation depth and adjacent structural conditions. For standard residential loft conversions, single-beam wall removals and rear extensions we work from your measured survey, architectural drawings and a set of clear site photographs without a separate visit.
Three featured structural packs delivered to London architects, developers and homeowners in the past quarter. Anonymised for client confidentiality — full project case studies available on request.
Victorian terrace, SW18. Hip-to-gable loft conversion with a 5-metre clear-span UB 203x133x30 ridge beam, supported on twin padstones into the existing party walls. Full pack delivered in four working days, IStructE signed and accepted by Wandsworth building control without query.
Edwardian semi, NW3. Full basement dig to 2.5m below existing ground-floor slab, traditional underpinning in 1.2m bays, reinforced-concrete retaining wall to Eurocode 2 and a party-wall protection scheme. Coordinated with the party wall surveyor and CDM principal designer.
Victorian terrace, E8. Wraparound side-return and rear extension with twin UB 254x102x28 steels meeting at a new corner column on a pad foundation. Full structural drawings issued direct to the steel fabricator; Building Regs approval first-time with Hackney building control.
We deliver structural calc packs across all 33 London boroughs — from Victorian terraces in Hackney and Islington to mansion-block reconfigurations in Kensington and basement digs in Westminster. Fixed travel-inclusive fees, no surcharge for inside the M25.
Calc pack landed four days after we sent the architectural drawings, perfectly cross-referenced and signed off. Building control approved first-time and the fabricator priced from it straight away. Saved us a fortnight on a tight programme.
Leave your number and a chartered structural engineer will call you back within 30 minutes during working hours (Mon-Fri 9-6, Sat 10-4).
No obligation. No sales pressure. Just expert advice.
Fixed fee from £495. Free quote in 60 seconds. IStructE chartered. Covers every London borough.
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