Inside a dense city site: sequencing the first 100 days below ground

With neighbours on three sides and no room anywhere on the plot for a laydown area to store materials ahead of need, the team behind a new mixed-use block spent more time working out the sequence of operations than working out the schedule itself. The first 100 days below ground were planned almost hour by hour, because on a site this constrained, the schedule was really just a consequence of getting the sequence right rather than something that could be planned independently of it.

Start with the logistics, not the structure

Deliveries were booked into fixed, narrow time slots rather than a general daily window, and reinforcement arrived pre-cut and pre-bent from the supplier so that nothing had to be processed or stored on site waiting for the next stage of work. The site manager says the single biggest saving on the whole substructure came not from any clever piece of engineering but from a simple discipline: refusing any delivery that did not already have a confirmed place to go the moment it arrived, since a delivery with nowhere to go on a site this tight does not simply wait quietly, it blocks something else.

Pour in zones, strip in the same order

The basement was divided into a series of pour zones sized so that each one could be formed, reinforced and cast in a single repeating cycle, small enough to keep the cycle short but large enough that the crew was not constantly resetting for a new zone. Formwork moved from one zone to the next strictly in the order each was released, rather than wherever happened to be convenient on a given day, which kept the same crews and the same equipment working continuously through the sequence instead of standing idle waiting for the next available zone.

Managing a site with no room to store anything

On a conventional site, a delayed delivery or a slow crew can often be absorbed by shifting material to a laydown area and working around the gap. This site had no such buffer, which meant every part of the plan had to assume deliveries would arrive exactly when needed and be used almost immediately. That assumption forced a level of coordination with suppliers that would have been unnecessary on a more spacious site, weekly calls to confirm exact delivery windows, and a standing rule that any supplier who could not commit to a fixed slot was not used for time-critical elements of the sequence.

Keep edges protected from day one

Edge protection was installed as each slab was cast, immediately, rather than being added later once the crew had already started working next to the newly formed drop. The red guardrails visible across the site in progress photos are part of the plan itself, built into the sequence at the point each zone is completed, not an afterthought bolted on once someone noticed the hazard.

Coordinating with the neighbours, not just the site

With occupied buildings on three sides, the team also had to plan around noise, vibration and access constraints that a more isolated site would not face at all. Piling and excavation methods were chosen partly for their vibration profile, not purely for speed, and a rolling schedule of noisy activities was shared with the neighbouring buildings’ managers ahead of time, which the project team credits with avoiding almost all the formal complaints that similar dense-site jobs nearby have faced.

What they would do again

Weekly sequence reviews with every subcontractor physically in the room, not represented by an email update, and a shared board visible to the whole site team showing exactly which zone was next in the cycle. Small conflicts between trades, a formwork crew and a reinforcement crew both wanting the same zone on the same day, were resolved face to face on a Monday instead of quietly becoming a lost day of production by Friday.