Structural engineering firm: load assessment and feasibility of your fit-out

Admissible operating loads in a commercial office follow a tiered usage grid:

• 250 kg/m² for a standard office,
• 350 kg/m² for a light archive room,
• 500 kg/m² for a library or technical room,
• 600 kg/m² for a server room or compactus.

Any densification, any change of use or any addition of a heavy partition alters the load assessment and creates a risk of excessive deflection or cracking. Our experience in supporting commercial projects shows that the vast majority of structural failures result from a lack of upstream verification, and not from a risk of immediate collapse. The stakes are threefold for real estate departments and asset managers: regulatory compliance (ERT, ICPE), occupant safety, asset value preservation. Densified flex office operations or those incorporating heavy collaborative spaces such as tiered seating or 400 kg acoustic booths systematically trigger a formal calculation note signed by an accredited structural engineer.

For the Asset Manager and CFO: what the load assessment does to asset value

The structural engineering firm is not a technical line item: it is a lever for asset value enhancement and OPEX/CAPEX security. Three financial perspectives shape the decision.

Asset value and due diligence. A complete structural file (original calculation notes, Eurocode verification, load capacity reserve memo) is systematically requested at the point of sale by notaries, asset managers and real estate brokers. Its absence translates into a discount or a blockage at the signing stage.

Occupancy ratio optimisation. Upstream structural validation makes it possible to significantly optimise the occupancy ratio, where cautious assumptions would have led to underusing the available area. On a floor plate leased at the Paris market rate, gaining a few tenths of a workstation per m² represents substantial avoided rent over the term of the lease.

Control of site variation orders. Integrating the structural engineering firm from the feasibility stage sharply reduces variation orders linked to structural discoveries during the works and saves several weeks on the schedule. For a CFO, this is the difference between a fixed works budget and a sliding budget.

Contrarian position. Contrary to the widespread practice of systematically commissioning a structural engineering firm at the start of a project, Kytom recommends a short visual pre-diagnosis (1 to 2 days) before committing to any heavy study. On post-2010 floor plates with accessible original calculation notes, the full study adds little additional value compared with a simple consistency check.

The Kytom method in 5 steps calibrated over 12 weeks

The intervention of the Kytom structural engineering firm follows five steps aligned with the average lead time of a fit-out project, with a single structural engineering referent per project to guarantee the documentary traceability required by environmental certifications in operation.

1. Document collection (3 to 5 days): original plans, calculation notes, as-built documentation, technical diagnostic reports from the owner or property manager.
2. Technical site visit: survey of grids, slab thicknesses, floor type (poured concrete, precast slab, composite, hollow-core) and identification of existing load paths.
3. Modelling and Eurocode calculations: validation of load capacity against projected loads, with a calculation note deliverable signed by an accredited structural engineer.
4. Costed recommendations: from repositioning heavy furniture to reinforcement with steel beams, carbon plates or composite decking, with reinforcement budgets varying according to the nature of the works.
5. Execution monitoring and structural acceptance report, including coordination with the other trades to secure the cohabitation under the raised floor of air ducts, electrical, structured cabling and condensate lines.

When this full method is not justified. On a floor plate of less than 400 m² retaining its standard office use, without densification beyond 0.6 workstation/m² or the addition of heavy space (archives, server, acoustic booth > 250 kg), a visual pre-diagnosis without a formal calculation note is generally sufficient. Commissioning a full structural engineering mission at €3,500-7,000 excl. VAT for this scope generates a negative ROI: the study expense exceeds the residual structural risk.

Measured benefits and points of attention: co-ownership, surveys, ERT

Integrating a structural engineering firm from the feasibility stage produces four concrete effects on operations: a significant reduction in variation orders linked to structural discoveries during the works, schedule gains thanks to the upstream validation of heavy layouts, occupancy ratio optimisation, and the build-up of a technical file that adds value in due diligence.

Several constraints nonetheless frame the study. Destructive surveys (core sampling, sclerometer, radar) generate additional study costs and extra delays that should be anticipated in the overall schedule.