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Elliot Lake inquiry looks into failed roof waterproofing

March 8, 2013, Elliot Lake, Ont. - The company whose waterproofing of the ill-fated Algo Centre Mall failed from the get-go had never before used its system on a similar structure, a public inquiry heard Thursday.

March 8, 2013
By The Canadian Press

 

In his testimony, Dave Monroe, former vice-president with the Harry S. Peterson Co., said he had reservations about the mall’s design but that his company wanted the job.

“We did comment about the risk involved,” Monroe testified.

“This was a basic structural decision that was being made and we had to accept that if we continued wanting to be involved.”

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Monroe’s Michigan-based company already had extensive experience in waterproofing.

Among its projects was
one at a parking garage at Toronto’s international airport — then the
world’s largest parking structure. The company also had success with a
new method at city landmark Casa Loma.

The experimental, cheaper “strip-membrane” system, had worked well, Monroe said.

Basically, the
“Peterson system” involved using a composite sealant and polyurethane
membrane only at critical joints in the concrete, rather than applying a
membrane across the entire surface.

However, unlike previous projects, the mall’s rooftop garage used precast hollow concrete slabs resting on steel beams.

“The hitch was that we were changing structures, that being new to our experience,” Monroe said.

Despite the novelty, he said, the company was confident it would succeed at the new mall by “tweaking” its system.

In his 1979 pitch to
the mall’s original owner, Algocen Realty, Monroe urged acceptance of
the new system as “the best long-term solution.”

He cited fewer problems, lower maintenance costs, and lower initial expense.

Algocen accepted the
proposal for $380,000 — saving $150,000 over conventional waterproofing
Monroe’s company could have installed.

The installation was
delayed several weeks because the building project was behind schedule,
causing temperature and humidity problems for the integrity of the
sealant materials.

Despite adverse weather, Algocen pressed Peterson to get on with the project.

“We proceeded under some less than ideal conditions in order to satisfy the requests and demands of Algocen,” Monroe testified.

“There was a lot of pressure to get this work done before the hard winter set in.”

Right away, the
rooftop garage began showing increasingly serious leakage problems, with
water pouring into stores below the parking deck.

A series of letters from Algocen to Peterson outlined the ongoing problems, demanding “urgent action.”

“A complete summer has
gone by and your company has not been able to correct these
deficiencies and give us what we contracted for, namely a water-tight
parking deck and canopy,” Algocen wrote Monroe in November 1980.

In part, Monroe blamed
the problems on unusual traffic flows across the deck — snow plows and
traffic using the garage as a “street shortcut” to avoid backups at a
nearby light.

He did, however, admit to a Peterson design flaw — using the wrong material to seal an expansion joint given the traffic.

Numerous attempts at remedy failed, with Monroe admitting he couldn’t figure out a solution.

Normally, steel
enclosed in concrete is well protected by the alkaline environment, but
chlorides used on roads lowers the alkalinity.

Investigators believe
the result was corrosion of the steel substructure, ultimately leading
to the catastrophic failure of a critical weld.

In June last year, the roof collapsed suddenly, killing two women in the mall below.

The inquiry, under
Commissioner Paul Belanger, is looking into the causes of the collapse
and the emergency response to the disaster.

Monroe, who has yet to face cross-examination, continues his testimony Friday.


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