Short answer: start with the installation zones and work backwards through the information, materials, access and preceding works each zone needs. Then test labour assumptions against the number of genuinely available workfaces. Keep separate time for snagging and any testing or handover support included in scope.

Inputs that set the duration

  1. Design releaseRecord when coordinated drawings, schedules and details must be approved to support procurement and installation.
  2. Material lead timeSeparate standard ductwork from bespoke fittings, equipment and specification-dependent components. Confirm who is procuring each item.
  3. Workface availabilityDefine what “ready” means for each area: structure, openings, access, preceding trades and safe working space.
  4. LogisticsAllow for delivery slots, unloading, storage, goods lifts, riser access and movement of large sections to the workface.
  5. Trade sequenceCoordinate ductwork with containment, pipework, ceilings, fire stopping, insulation and equipment connections.
  6. Close-outAllow time for inspection, snagging and agreed records before downstream activities or handover.

Plan by zones and constraints

A single overall duration can hide the actual sequence. Break the package into floors, risers, plant areas or other workable zones. For each one, identify the release date, planned activities, material requirement, access method and dependency on another contractor.

Mark constrained resources separately. One goods lift, one riser opening or one technical decision can limit the output of several operatives. More labour does not remove a constraint that prevents access or material flow.

Connect labour to available workfaces

Crew size should follow the amount of productive work available. Use the companion guide on ductwork installer crew size to review workfaces, access and supervision. If only one zone is released, a larger team may increase congestion rather than progress.

Programme review questions

  • Are the drawing dates aligned with procurement lead times?
  • Which areas are genuinely ready, and who confirms release?
  • Are delivery and storage arrangements compatible with the sequence?
  • Which interfaces could stop installation?
  • How quickly can programme-critical queries be decided?
  • Is close-out time visible rather than absorbed into installation?

When the programme changes

Compare the revised sequence with material orders, labour allocation and access. Record blocked workfaces and decisions separately from general progress. If an area moves, identify whether the team can transfer productively to another agreed zone before changing headcount.

Our article on ventilation installation delays covers common blockers. The guide to ductwork coordination explains why drawing and site interfaces matter to the sequence.

How Cliventa reviews programme suitability

Cliventa reviews programme requirements alongside drawings, specification, scope, procurement responsibility, access and available workfaces. A proposed duration remains subject to those project conditions and any later approved changes.