High-Density Residential Tower — Auckland
CPI breached 0.95 at 15% complete; recovery plan resequenced facade and switched one subcontractor. Net cost recovered, six-week schedule slip absorbed in float.
- Value
- $68M
- Duration
- 28 months
- Outcome
- Recovered
- CPI red at 15%
- Facade lead time slip
- Two open interfaces with services
- Rules of credit must be agreed before mobilisation
- Lead-time tracking belongs on the critical path, not the procurement log
- Interface forum cadence is non-negotiable on multi-package jobs
Project context
A 32-storey high-density residential tower in inner Auckland, 184 apartments above three levels of basement parking and a ground-floor retail podium. Gross floor area was approximately 28,000 m². The contract was a lump-sum design-and-build, NZS 3910 amended, with a Tier-1 New Zealand main contractor and a developer client raising debt against pre-sales. The site was a tight inner-city footprint with two boundaries on live streets, a heritage masonry party wall on the third boundary, and an existing easement for a stormwater main running through the south-east corner. Programme at award was 28 months including a six-month basement and substructure phase. Pre-sales at award covered 62% of the apartments, which set the financial pressure that shaped almost every recovery decision later in the job.
The early warning at 15% complete
By the end of month 5 the project was 15% complete by earned value but the cost performance index had dropped to 0.94. The trigger was not a single event but three converging signals: the basement excavation had run 11 days long because of unmapped fill from a previous demolition, the facade unitised panel supplier had pushed the first shipment back by four weeks citing a sub-supplier glass issue, and the mechanical services interface with the structural post-tensioning was generating two RFIs a day with no clear owner. Individually each was manageable. Together they were burning roughly NZD 180,000 a week in non-productive labour and prelims. The site team flagged it at the monthly cost review and the project director called a five-day stand-down of forward planning to redesign the next nine months of the programme rather than continue to grind.
The recovery plan: resequence the facade, replace one sub
The recovery plan made two structural changes. First, the facade installation sequence was flipped from bottom-up to a split sequence: the lower 12 floors continued bottom-up while the top 14 floors were installed top-down from a temporary mast climber, allowing the unitised panels to be received from the supplier in two parallel streams as production caught up. This change required a temporary works re-design and an additional resource consent for the mast climber, both of which were obtained inside three weeks. Second, the mechanical services subcontractor was replaced. The original sub had been awarded on price but had repeatedly missed shop drawing dates, and the cost of the missed dates was now exceeding the original tender saving by a factor of four. The step-in was executed under the subcontract's default clause with 14 days' written notice, the replacement was on site within five weeks, and the handover of partly installed works was documented in a joint inspection report that became important six months later when the original sub disputed the final account.
How rules of credit changed the conversation
One of the most important lessons from this project was that earned value only works if the rules of credit are agreed in writing before mobilisation. On this job, rules of credit had been agreed verbally but not documented for three control accounts: the facade, the in-situ concrete, and the mechanical services rough-in. The result was that every monthly progress claim turned into a negotiation rather than a calculation. After the recovery plan was approved, the project controls manager rewrote the rules of credit for all 42 control accounts in a single two-page document, signed it with the Engineer, and from month 7 onwards the monthly EV claim was approved without amendment in 21 of the next 22 cycles. The same discipline applied to the replacement mechanical sub from day one of their appointment.
Interface management on a multi-package job
The project had 11 separate subcontract packages and three nominated suppliers. The original interface management was handled inside the weekly site meeting, which meant interface issues competed for airtime with safety, quality and progress. The recovery plan introduced a dedicated 30-minute interface forum every Tuesday morning, with a single interface register owned by the project engineer, and a hard rule that no interface item could sit in the register for more than 14 days without an escalation. The forum closed an average of six interface items per week from month 8 onwards. The lesson is that interface management is a separate discipline on multi-package jobs — folding it into the general site meeting guarantees that it loses to whatever is louder that week.
Cost recovery and the six-week schedule slip
By month 18 the project was back to a CPI of 0.98 and an SPI of 0.96. The net cost impact of the recovery plan, including the facade re-sequence, the mast climber, and the sub replacement, was NZD 2.1 million against a contingency reserve of NZD 3.4 million. The six-week schedule slip from the early months was absorbed by a combination of float on the fit-out trail and a two-week acceleration of the lift installation, which was paid for at NZD 140,000 in premium time. Substantial completion was achieved 18 days after the original contractual date, inside the 30-day grace period in the contract, with no liquidated damages applied. The developer's pre-sale settlements all completed inside the funding agreement window.
What this project says about residential towers
Residential towers of this scale fail in predictable ways: facade procurement, mechanical interfaces and basement ground conditions. The successful projects do not avoid these risks — they detect them inside the first 90 days and resequence rather than grind. The most expensive thing a project director can do in month 5 of a 28-month tower is to pretend that a CPI of 0.94 will self-correct. It will not. It will get worse every month until the contingency is gone and the only remaining lever is acceleration, which is the most expensive lever on the panel. Cheap recovery is early recovery.