Phasing of works in occupied offices: the 4-step Kytom method, project phases, phased schedule and controlled cohabitation over ~12 weeks.
"How do we organise things with the teams"
A poorly phased day of work costs on average 180 euros per affected employee. On a floor of 80 people, that represents 14,400 euros lost in productivity for each day of unanticipated disruption. The overtime hours at night to make up for the delay increase the bill by 25 to 40%.
Unphased work sites record 31% more sick leave, mainly linked to acoustic stress and degraded air quality. HR teams also note an 18% increase in turnover within the 6 months following a poorly managed project, particularly among managers in open-plan spaces.
Regulations require the physical separation of work zones from occupied workstations. A phasing failure exposes management to an immediate work stoppage by the inspectorate, as well as a fine of up to 10,000 euros per infringement observed during a CSSCT inspection visit.
Since 2006, Kytom has been managing operations on occupied sites according to a logic of calibrated project phases. Each phase covers 150 to 250 m² deliverable in 2 to 3 weeks, with a secured buffer zone and a schedule communicated to teams 15 days before the start. Our 11 agencies deploy a site manager dedicated to phasing, who coordinates internal relocations, furniture deliveries and technical interventions. Across 1,200+ delivered projects, 94% have respected the planned cohabitation without interrupting business activity. We systematically include an internal communication contact on the client side, validate noisy slots outside meeting hours, and measure acoustics at the zone boundary to stay below the 55 dB(A) recommended by ANACT.
Audit of flows, uses and operational constraints over 5 to 10 days. Mapping of critical zones (server rooms, client spaces, sensitive workstations). Deliverable: cohabitation matrix validated by management and the CSE, with an initial acoustic survey and updated evacuation plan.
Breakdown into phases of 150 to 250 m², sequenced according to team availability and activity peaks. Definition of buffer zones, authorised noisy hours and separate site access. Deliverable: phased Gantt schedule over 12 weeks, validated on a contradictory basis with employee representatives.
Detailed design by phase, furniture selection (Vitra, Herman Miller depending on budget), validation of acoustic prototypes in the showroom. Coordination with the trades to limit co-activities. Deliverable: tender documents by lot, technical sheet per phase and weekly internal communication plan.
Execution phase by phase with a biweekly site meeting and a team check-in on Fridays. Partial acceptance after each phase, clearance of reservations within 5 days. Deliverable: acceptance report, as-built documentation (DOE) and a formalised feedback report for the next phases.
"We renovated 1,400 m² while keeping 110 employees on site. The breakdown into 6 phases and the weekly check-ins completely defused the teams' concerns."
On average 4 to 6 phases of 150 to 250 m², depending on occupancy density and business constraints. Kytom sets each phase at 2 to 3 weeks of execution, with a buffer zone of at least 3 metres between works and occupied workstations.
Yes, a prior consultation of the CSE on working conditions is mandatory before the works begin. Kytom provides a technical CSE file within 10 days, including the phased schedule, projected acoustic measures and an updated evacuation plan.
The additional cost ranges between 8 and 12% compared to an empty site, linked to reinforced protections, interventions outside working hours and daily cleaning. This additional cost remains lower than a temporary relocation (180 to 320 euros per workstation per month).
We schedule noisy tasks (drilling, demolition) in validated slots, generally 8am-9.30am and 5pm-7pm. An acoustic survey at the zone boundary guarantees less than 55 dB(A) in occupied spaces, the reference threshold for intellectual work.
An occupied site takes 15 to 25% more time vs an empty site. For 850 m², expect 14 to 16 weeks instead of 12. This timeframe remains well below the cumulative 4 to 6 months of a back-and-forth relocation.
Kytom appoints a lead site manager, who co-runs a weekly check-in with the client contact (HR director or office manager). A 2-page site newsletter is distributed every Friday to all 80 to 150 employees concerned.