"This project is classified as high-risk. Almost all buildings are vacated when being reclad. Internationally there have been few examples of recladding in a live hospital environment and none that have been found to replicate this project," the paper said.
"This work's methodology is untried in New Zealand but has been tested in a limited way. The works methodology is intended to enable the Scott Building to continue to function as an acute hospital while the remedial work continues.
"The evident risks involved here have been mitigated as far as practicable ... while attracting a not insignificant level of risk, the remediation work is very necessary and must proceed to ensure the Scott Building's integrity and long-term use."
Among the risks is that of harmful spores entering the clinical space, disturbed by building work on the rotting and mouldy building. The spores could be dangerous to patients with low immunity, the paper said. Other risks include excessive noise and vibration, in which case patients would have to be moved elsewhere or work would have to stop.
The Scott Building, which has 258 beds, houses acute medicine, surgical and coronary care patients, as well as the renal dialysis day unit and cardiac catheterisation lab.
A spokesperson for the DHB said it was working closely with Hawkins to develop a remediation method that would minimise any risk to patients and staff.
"When work starts we will have in place all the necessary precautions. The designed methodology will be carefully adhered to throughout. This will include regular monitoring and checking by infection control teams. They will sign off our progress for patient and staff safety every step of the way.
"Construction work has been tailored to mitigate disruption and allow patient care to continue throughout with careful selection of tools for the work at hand alongside physical barriers to address noise transfer and keep out any debris."
The project is expected to be completed in 11 stages over two and a half years.
Health Minister David Clark declined to comment yesterday, saying the way the building would be remediated was an operational matter.
In a statement in March to announce the funding, Clark said: "It is important to note that the DHB's advice is that patient safety is not at risk as long as any rot and mould are contained in the walls. That will be of little comfort to the people of Counties Manukau who rightly expect that their hospitals are up to scratch."
The Scott Building was built between 2000 and 2006. A large cladding panel fell off the building on to a footpath in 2012, signalling widespread weathertightness issues. The building has since been found to be rotten and mouldy in places, and with sewage leaks because the PVC sewerage pipes are failing.
Remediation had been due to start in 2013 but Counties Manukau District Health Board was locked in a drawn-out process with the builder, Hawkins, over a $12m settlement from the builder. It eventually settled for $3m.
Clark announced the extra $11.5m for the remediation project in March after visiting Middlemore Hospital just over a week earlier to see for himself the scale of the problem. That took the total cost of the project, to be done again by Hawkins, to $27.5m.
The previous National government signed off on $13m of the estimated $16m cost to reclad the building in September last year.
The extra $11.5 million includes $2.5 million to deal with more potential sewerage problems as the cladding is removed.
Despite downplaying the issue of sewage leaks as stains on the ground that required clean-up with a bucket of water, the DHBasked for the $2.5m contingency in case more sewerage problems were discovered.
As well as the sewerage work contingency, the DHB's costs have increased by $4.59m, including a significant increase in contingency.
Hawkins required another $4.41m, taking its total to remediate the building to $18.23m. This was due to an extended timeframe, more timber needed because of further deterioration and to reflect cost pressures in the Auckland construction market.
TIMELINE
• Built between 2005 and 2006 a large cladding panel falls off the Scott Building in 2012. Checks reveal weather tightness problems and leaking.
• 2016 - Leaking issues outlined to Ministry of Health, according to DHB
Nov 2017 - Independent surveyor Alexander and Co report for DHB outlines problems with buildings
• March 13 – David Clark visits Middlemore, where he says he was told about rot, mould and sewage in Scott Building but no other buildings.
• March 20 (circa) - Government approves additional $11.5m towards repairs in Scott Building.
• March 22 - RNZ reports based on OIA that four hospital buildings are full of rot and mould. Health Minister David Clark says he knew about only one, the Scott
• March 27 - DHB says it did not do repairs because Coleman wanted it to stay in surplus
• April 3 - DHB confirms report of major power supply failures at Middlemore and Super Clinic since 2017
• April 12 - Rabin Rabindran reportedly tells Clark he is stepping down as acting chairman after the minister wrote to him and another board member about their positions.
