design and build method in 5 steps calibrated over 12 weeks
According to INSEE (Tableaux de l’économie française, 2024 edition, « Employment by sector » sheet), the tertiary sector represents more than 75% of French salaried employment, i.e. around 20 million positions spread across heterogeneous space typologies. Kytom segments its work into 6 sectors:
- Services and consulting: flexible floors, modular meeting rooms, acoustic focus rooms.
- Finance and insurance: enhanced confidentiality, secure airlocks, GDPR compliance, acoustic partitioning per NF S 31-080 (« high comfort » category).
- Industry and tech: linkage between tertiary zones and production zones, ICPE compliance, secure R&D.
- Healthcare and laboratories: HAS reference frameworks, dedicated clean/dirty circulation, cleanable materials, technical rooms.
- Public and non-profit sector: ERP, accessibility for people with reduced mobility (order of 8 December 2014), public procurement.
- Real estate and asset management: rental value enhancement, BREEAM, HQE, WELL certifications.
Our reading differs from the profession’s dominant discourse on this specific point: the « universal agile office » doxa pushed by the big furniture names underestimates the weight of sector-specific constraints. In practice, a tech open space transposed as-is into finance frequently fails on the NF S 31-080 acoustic criterion, and a « standard healthcare » fit-out without dedicated clean/dirty circulation is rejected by the HAS committee. Sectorisation is not a commercial affectation, it is a condition of acceptance.
Tertiary buildings account for a significant share of national CO₂ emissions, which calls for heightened vigilance on the tertiary decree.
The Kytom approach is structured in 5 contractually locked phases.
- Sector audit (weeks 1-2): dedicated space planner, occupancy counts, user interviews, sector-specific regulatory review.
- Programming and design (weeks 3-5): 2D/3D deliverables, technical plans for all trades, detailed costing.
- Regulatory validation (weeks 5-6): Labour Code (R4213 lighting, R4222 ventilation), ERP, accessibility, ICPE for industry; coordination with inspection bodies.
- Single-contractor execution (weeks 6-11): a single site supervisor across 8 to 12 trades, one sole contractual point of contact.
- Delivery and after-sales service (week 12): snagging, as-built documentation, extended warranty of 12 months minimum.
| Step | Duration | Key deliverable |
|---|---|---|
| Audit | 1-2 wks | Sector scoping note |
| Design | 3 wks | Preliminary design, detailed design, costing |
| Validation | 1-2 wks | Inspection body opinion |
| Works | 5-6 wks | Partial acceptance |
| Delivery | 1 wk | As-built file, after-sales |
ISO 9001 and Qualibat certifications frame the processes; the BREEAM (BRE), HQE (Certivea) and WELL (IWBI) reference frameworks can be mobilised from the programming stage.
When this method is not the right one. Single-contractor design and build ceases to be relevant below 150 m² of fitted area (overhead costs amortised over too few m², a cost/m² ratio noticeably less favourable than a direct arrangement) or when the client wishes to retain a direct contractual relationship with each trade (headquarters with an internalised real estate department and framework contracts in place). In these cases, an arrangement with separate work packages managed by a project management assistant (AMO) remains more rational.
For the business decision-maker: what each sector actually measures on delivery
The success criterion is not the same depending on the function managing the fit-out budget. Reformulated by dominant persona:
- CFO / Asset Manager: what matters is the rent avoided through reasoned densification and the horizon of return on capital. Reasoned densification of an 850 m² floor can free up a significant area, generating substantial avoided rent in the Île-de-France tertiary zone and a medium-term return on real estate investment.
- HR Director / Office Manager: the trade-off plays out on attractiveness and retention. Employee feedback gathered after acceptance regularly reports a noticeable improvement in acoustic and visual comfort, consistent with Actineo observations on workstation satisfaction.
- Legal / compliance department: the useful reading is that of penalties avoided. Labour Code Title I (R4211 to R4217), order of 8 December 2014 on accessibility, mandatory energy declaration for tertiary buildings over 1,000 m²: a failure to comply with the tertiary decree exposes the company to a published administrative penalty. Locking in phase 3 (regulatory validation, weeks 5-6) covers this risk contractually.
- CIO: the reading grid is the low-voltage infrastructure, the building management system and energy sub-metering, to be instrumented from the design stage and not as a retrofit.
Other indicators on our sector operations: the cost/m² ratio ranges from €1,200 to €2,800 depending on the level of specification, a range consistent with the ARSEG Buzzy Ratios 2023. The design and build arrangement makes it possible to noticeably reduce lead times compared with an arrangement using separate work packages, and to keep change orders to a controlled level.
Sector-specific points of attention: occupied sites, ABF, ICPE and tertiary decree
Several constraints deserve to be anticipated from the upstream phase, depending on the sector concerned.
- Sites in continuous operation (healthcare, industry, finance): phasing by zones, work during off-peak hours or over 2 to 3 consecutive weekends, with an extended schedule to factor in from the scoping stage.
- Buildings in ABF sectors (central Paris, heritage sites): prior authorisation from the Architect of the Buildings of France (Architecte des Bâtiments de France), an additional 2-month review period for façades and exterior joinery.
- ICPE sites (industry, laboratories): compatibility of the tertiary fit-out with the prefectural operating order, separation of flows, specific smoke extraction.
- Tertiary decree: mandatory annual declaration for buildings over 1,000 m²; integration of sub-metering and the building management system from the design stage (phase 2) to avoid a subsequent retrofit.