Apartments are the single biggest segment of the Australian residential construction market — by some counts, 255 active towers and large multi-residential projects are running concurrently across the east coast. Multiplex, Mirvac, Lendlease, Deicorp, Cbus, Meriton, Crown Group, Coombs, Bathla, and Toplace are all running tight programmes on these jobs. The single metric that decides whether the head contractor finishes on margin is floor cycle time. And the single most underexamined input to that cycle is how concrete cutting and coring is sequenced into the trade flow.
The honest version is this: on a typical 25-storey apartment tower, poor cutting sequencing costs the head contractor an average of two weeks per floor over the life of the build. That is not a rounding error. That is the float that disappears between handover and liquidated damages.
Where the Two Weeks Actually Goes
The two weeks per floor is not a single delay. It is a stack of small ones. Plumbing penetrations cut after the formwork team has stripped, but before the wet trades are mobilised. Electrical core holes drilled after services have started to be installed, requiring rework. Hydraulic risers cored after the floor has been broomed clean, requiring it to be re-cleaned. A typical 25-floor tower will see between 80 and 140 penetrations per floor — each one a potential clash with another trade if the sequencing is not pre-planned. Every clash is half a day, and half a day per clash, across all the penetrations, is how a tower loses two weeks per level.
The Schedule That Most Towers Run
The typical apartment cutting schedule is reactive. The cutting and coring contractor turns up when the head contractor calls, the marks are placed by whichever trade got there first, and the work is done floor-by-floor based on whoever is loudest in the daily meeting. That works, in the sense that the work eventually gets done. But it does not optimise for the floor cycle. The cutter cuts what is in front of them, and the structural and mechanical work waits for the cut to be finished. Multiply that across 25 floors and the cumulative drag on the programme is measured in weeks, not days.
The Schedule We Would Run Instead
The optimised approach treats cutting and coring as a programmed trade, not an on-call service. Penetrations are coordinated three floors ahead of the saw, with a single coordinated mark-up sheet signed off by the formwork supervisor, the hydraulic contractor, the electrical contractor, and the head contractor’s engineer. The cutting team mobilises on a fixed window per floor — typically 36 to 48 hours, depending on the penetration density — and clears the entire floor in one pass. That allows the wet trades to start clean on day three, not day six, and the floor cycle pulls in by 8 to 12 days per level.
A Real $200M Tower, Real Numbers
On a recent $200M apartment tower we worked on across 26 levels, the head contractor moved from a reactive cutting schedule on the lower floors to an optimised one from level 8 upwards. The cutting and coring time per floor dropped from a measured average of 4.5 days to a measured average of 1.5 days. The trade-clash count per floor dropped from an average of 7 to an average of 2. Across the remaining 18 floors, the cumulative time saved on cutting alone was 54 days. The float that bought the project was used to absorb a weather delay later in the build, and the project handed over on time.
What Construction Managers Should Insist On
There are four practical things every Construction Manager should be asking for on an apartment cutting scope. A pre-construction sequencing meeting with the cutting contractor, the formwork supervisor, the hydraulic lead, the electrical lead, and the head contractor’s engineer — held before the first floor is cut, not after. A single coordinated penetration drawing per floor, version-controlled, with sign-off boxes for each trade. A fixed cutting window per floor, with a defined start and end, written into the programme. And a tier-rated cutter who can mobilise three floors at a time, not one.
The Coring Sequence Nobody Plans For
The single most under-planned activity in apartment cutting is the coring sequence for vertical services — the hydraulic risers, the mechanical risers, the electrical penetrations that pass through every floor. On most towers, the coring is done floor-by-floor in vertical sequence, which means the saw operator is repeatedly setting up, decommissioning, and resetting their water management, slurry control, and core stand. A vertically-sequenced coring run, where the same riser is cored down the entire stack in a single mobilisation, takes a third of the time and produces a third of the slurry waste. Most towers do not run it that way because it requires the structural completion of the stack — but the ones that do are the ones with the shortest floor cycles.
Slurry and Water Management — The Programme Killer
Concrete cutting and coring produces slurry and water. On an apartment tower, that slurry has to be contained, captured, and disposed of, and the disposal route has to be agreed with the head contractor and the principal. The single most common reason a cutting contractor blows their floor window is slurry containment problems — water finding its way to a lower level, slurry breaching a bund, or the disposal route being unavailable when needed. The towers that run the optimised cutting schedule are the ones that have planned the slurry pathway floor-by-floor, with the same rigour as the cut itself.
The Discipline That Buys Back the Float
Apartments are won and lost on the floor cycle. The contractors who run the tightest cycles are the ones who have pulled the small disciplines — cutting sequencing, coordinated penetrations, vertically-sequenced coring, planned slurry pathways — into the same programme rigour as the structural pour itself. Concrete cutting looks like a small trade. On a 25-storey tower, sequenced badly, it is the trade that quietly costs you two weeks per floor. Sequenced well, it is the trade that buys back the float you thought you had lost.
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