Fitting Out an Occupied Office

What actually changes

The belief is that fitting out an occupied office while people work is the same job as refurbishing an empty one, done a little more politely. It is not. The scope is the same: the same partitions, ceilings, services and finishes. The programme is different in almost every respect.

On an empty floor, work can run across the whole area at once, at any hour, with services shut off as required. In an occupied office, every one of those freedoms is limited by the people still working there. The consequence for a decision-maker is that the date, the sequence and the cost of coordination all change, even though the drawings do not.

Phasing a fit-out in an occupied office

An occupied fit-out is built around phases: sections of the floor that are handed to the contractor, worked on, finished and handed back in turn.

The phasing plan answers four questions.

• How many areas are there, and how big is each? Larger phases finish sooner but need more people moved at once.
• Where do the displaced people go? This is the decant area, and it decides the size of every phase.
• In what order? Some areas have to go first because they hold services that later areas depend on.
• How is each phase handed back? Cleaned, tested and safe, before the next begins.

The decant capacity is often the real constraint. If only a small number of people can be moved at any time, phases must be small, and the number of phases and the overall duration follow from that. This is why the phasing has to be worked out with the client's facilities and HR teams, not just the contractor.

Noise and dust: move it, contain it

Two kinds of activity disrupt working staff most: noisy work and dusty work. Typical examples are demolition, breaking, drilling and cutting, chasing walls and sanding. The controls are of two kinds.

Move it. The noisiest and dustiest activities are scheduled for evenings and weekends, when fewer people are present. This is effective, but it has a programme cost: fewer productive hours, and overtime or shift working for the crew.

Contain it. For work that has to be done during the day, physical separation controls where the noise and dust go. That means solid temporary barriers rather than sheeting alone, sealed joints, controlled entry points, protection of ventilation and air-handling routes, and cleaning at the end of each shift.

Dust control depends more on sealing and discipline than on the barrier material. A well-built barrier with an unsealed gap, or a door left open, does very little.

Disruptions and the control that manages each

Disruption	Main control	What can go wrong
Noisy work	Schedule for evenings and weekends; agree quiet hours	Overrunning into working hours
Dust	Solid barriers, sealed joints, end-of-shift cleaning	Gaps at ceilings, doors and service penetrations
Vibration	Method choice; notice to affected teams	Working close to sensitive equipment
Power shutdowns	Agreed windows; temporary supplies	Undocumented circuits taking down other areas
Water and drainage isolation	Isolate by section; drain-down planned	Valves that do not isolate what the drawing says
Air-conditioning disruption	Zone isolation; protect return air paths	Dust drawn into occupied zones
Fire alarm and detection	Zone isolation with a defined procedure	Detectors left covered or zones left disabled
Escape routes	Protected, signed routes maintained	Temporary partitions blocking a route
Lifts and access	Booked windows; protected routes for materials	Deliveries competing with staff at peak hours
Deliveries and waste	Off-hours movement; designated routes	Debris carried through occupied areas

The table is not a checklist for every job. It shows a pattern: each disruption has a control, and each control has a place where it typically fails.

Services isolation and shutdown windows

Work on electrical, water, drainage and air-conditioning services usually requires them to be switched off or isolated. In an occupied building, that affects people.

The controls are agreements more than technology. Shutdown windows are agreed with the building's facilities team in advance, and each isolation has a defined scope, a duration and a person responsible for restoring it. Where a service must stay on, a temporary supply or bypass is arranged.

The recurring problem is that the building does not always match its drawings. An isolation valve or breaker that is expected to isolate one area turns out to serve another, and a shutdown meant for one department affects three. This is why the services survey, and the coordination of what is affected, is done before the shutdown, as described in the article on the MEP coordination drawing.

Building services provisions are set out in NBC 2016, Part 8.

Escape routes and fire-system continuity

This is the part of an occupied fit-out where care matters most, and where the guidance has to come from the building's own fire consultant and authority, not from a general article.

The framework is straightforward. While people occupy the floor, the escape arrangements that protect them must keep working. Temporary barriers must not block or lengthen an escape route without that being agreed. Fire detection and alarm zones affected by the works must have a defined procedure, so that isolating a zone to avoid false alarms from dust does not leave an area unprotected. Sprinkler isolations, if any are needed, must be planned, limited in duration and communicated.

Fire and life safety provisions, including occupancy and escape, are in NBC 2016, Part 4. What applies to a particular building, and what arrangements are acceptable during works, must be agreed with the building's fire consultant, the facilities team and, where relevant, the authority having jurisdiction. This is a matter to be raised at the start of planning, not on the day work begins.

Lifts, access and logistics

Materials, waste and people all use the same lifts and corridors. On an empty floor, that is a scheduling matter. In an occupied building, it competes with the people already there.

Lift bookings, protected routes for materials, and delivery times outside peak hours are worth planning explicitly. So are the access arrangements for the contractor's workforce and how each phase is separated from the occupied area at entry. Building management often has its own rules (see landlord fit-out guidelines) on when goods lifts may be used and how routes must be protected, and those rules become constraints on the programme.

Why the overall duration is longer

Putting the points together explains why an occupied fit-out takes longer than the same work on an empty floor.

• Work proceeds area by area, not across the floor at once.
• Each phase needs setting up and protecting before work, and clearing and testing after.
• Noisy work is restricted to certain hours, which reduces productive time.
• Shutdowns can only happen in agreed windows, so services work waits for them.
• Materials move at restricted times, through restricted routes.
• People moving in and out between phases take their own time.

None of these is a failure. Together they are simply what an occupied refurbishment is, and the honest programme shows it.

Common mistakes

Agreeing a completion date before the phasing is planned. The date depends on the number and size of phases, the decant capacity, the hours available and the shutdown windows. Fixing it first forces those to be squeezed later, usually at the expense of the people in the office.

Assuming the decant is free. Moving people costs time, and somewhere must have capacity for them.

Treating dust barriers as a one-off installation. They need inspection, repair and daily cleaning, not just building.

Leaving fire detection to chance. A detector covered to stop false alarms, and never uncovered, is a hazard that outlasts the works.

Not checking what an isolation actually isolates. The shutdown affects more than intended.

Keeping staff uninformed. People who know what is happening and when tolerate disruption better, and complaints tend to fall.

What to ask

• Has the phasing plan been drawn up, and who has agreed to the decant?
• Which activities will be done outside working hours, and what does that do to the programme?
• How are dust and noise contained during the day?
• Which services will be shut down, when, and for how long?
• How are escape routes and fire detection maintained during the works, and who has approved that?
• How are materials and waste moved through the building?
• How will occupants be informed?

Standards referenced

Fire and life safety provisions, including occupancy and escape, in NBC 2016, Part 4; building services provisions in NBC 2016, Part 8. Arrangements for maintaining escape routes, fire detection and alarm and sprinkler protection during works, and the permissions required for shutdowns, must be agreed with the building's fire consultant, the facilities team and the authority having jurisdiction.