PRESERVATION TECHNOLOGIES IN THE MEDIA
before
CP mesh laid under new balcony
after
Pioneer move electrifies apartments for long life
Truly “electrifying” news comes from Preservation Technologies
who has just completed the first installation on the NSW Central Coast
of impressed-current cathodic protection to residential apartments and
among the first half dozen done in Australia.
The move sets an example to residential
block owners, especially those near the sea, to take up a technology increasingly
used in bridges, wharves and other infrastructure assets for long term
protection against “concrete cancer”.
With admirable foresight, the owners’
corporation at Avoca’s “Marese” apartments on Avoca
Drive opted for the CP solution by Preservation Technologies over more
conventional options offering less certain longevity.
“Built in the ‘70s, the three-storey
walk-up was clearly facing corrosion-related problems due to chloride
ion attack from the salt air environment on its reinforcing steel,”
Preservation Technologies’ John O’Connell explains. “Now
renovated and protected by the latest in CP technology, the building can
look forward to 30-40 years trouble-free life extension.
“This is a far cry from other more
conventional measures, which cannot offer certainty even of their often
quoted ten year life.”
The general make-over of the building by
Preservation Technologies involved demolition including removal of the
old balconies, concrete repair, structural steel repair, new balcony screeds
and tiling, construction of reinforced hobs, brick work replacement, protective
coatings and installation of new frameless stainless steel balustrades.
“We installed a junction box at each
new balcony and ran wiring up through cavities to the roof, across the
roof and down to the switch room for connection to the transformer/rectifier
which will pass a low current through the building for the rest of its
days,” John explains, adding that all the wiring is hidden and protected
for the safety of tenants.
The current needed differs for each building.
It is precisely calculated per unit area of steel surface to be protected
and the CP equipment continues to monitor it throughout the life of the
structure.
“The impressed current shifts the
corrosion potential of the steel within the building away from a high
oxidation anodic state, effectively making the steel a cathode, and keeps
it there,” John says.
“The cost of running it is minimal
and, of course, it is infinitely less than most seaside owners’
corporations will pay out for chasing corrosion through their buildings,
cutting it out and repairing it when the sea air, unchecked by the protection
of impressed-current CP, wreaks its inevitable havoc and possibly even
makes their structures unsafe.”
Illustrating the safety aspect, John points
to the case in Manly where it was a miracle that no one was killed when
two cantilever balconies sheared off cleanly under their own weight because
their reinforcing steel had corroded so badly.
In addition to CP installation on residential
apartments, Preservation Technologies undertake structural strengthening,
building façade repair, heritage restoration, roof waterproofing
and infrastructure repair. One of the most prominent among their recent
projects is the heritage restoration of the façade of the NSW Teachers
Federation building in Surry Hills.
Released 7Sep06