February 25, 2013

Historic warehouse renovation features innovative use of concrete

OLIVER CAVANNA / IBI ARCHITECTS

A rendering shows what the renovated warehouse in Vancouver, B.C. will look like when complete.

PETER CAULFIELD

correspondent

A warehouse in Vancouver, B.C.'s Yaletown has been vacant for decades, but it's coming back to life thanks in part to a cast-in-place concrete addition to the original heavy timber structure.

The $10 million restoration will add about 22,500 square feet in five floors to the original six-storey, brick and beam warehouse, which was built in 1909.

It is located at 564 Beatty Street.

When the restoration is finished a year from now, the glass and concrete addition will consist of four full office floors, two restaurant levels, a rooftop social room and deck.

Jon Stovell, president of Reliance Properties Ltd., which bought the property for $5 million in 2010, said it is rare to add storeys to a building using cast-in-place concrete.

The more conventional method would be to use steel framing and metal decking.

“But, we found out that once we had taken everything into account, using concrete is not much heavier than the conventional method,” he said.

“In addition, the extra concrete works to improve the building’s seismic performance.”

Stovell said the added concrete floors will make the building more solid and enable the new structure to accommodate larger spans.

“The addition will have fewer columns and a smooth ceiling without beams to get in the way of air conditioning and ceiling finishes,” he said.

The idea to use cast-in-place concrete on the addition came from Robert Leshgold, Reliance Properties’ in-house architect.

“Before starting his working drawings, the structural engineer (John Bryson, of John Bryson and Partners) was discussing structural concepts with us,” said Leshgold.

“Up to that point, the structure had been conceived of in steel. However, I was dismayed about having a lot of exposed steel that all had to be covered up with fire rating, either in drywall or ugly spray fire protection.”

He said the idea of using concrete came to him because it has the required fire rating without any extra layers of protection.

“Given that I like the look of exposed concrete, it seemed like it might be both a cost savings and an aesthetic improvement,” he said.

“Further discussion led to the realization that beams and mid-span columns could be eliminated, raising the clear ceiling and creating (a larger) column-free area.”

Even though the technique of using cast-in-place concrete was untried, Leshgold thought it would work.

“It seemed like fewer parts and, therefore, perhaps less labour,” he said.

“Concrete was already there for the topping and core, so it was one less interface to make.”

He also thought the new method would be simpler.

“It meant we didn’t need another major trade, and a bigger job for the concrete contractor, so a larger-scale job would make us more efficient,” Leshgold said.

“Concrete was something the contractor (ITC Construction Group) was very familiar with, although at first he thought the idea was crazy... a heavy concrete thing sitting on top of a stick-and-brick heritage building. Normally the expectation is the relatively lighter steel.”

The structural engineer did his best to convince the contractor.

“At one point, the engineer thought it might be crazy, too,” Leshgold said.

“But they both finally came around and agreed it was the way to go. There was a cost difference of about three per cent to the project (using concrete instead of steel frame), but we figured it was worth it to get the column-free space in the addition, along with a higher, flat ceiling, without beams, that can remain exposed.”

Construction began in July 2012 and is scheduled to be completed in December 2013.

As of the end of January, ITC Construction’s project manager Liam Fitzpatrick said all of the excavating and the building core up to the fourth floor had been completed.

“Now we’re starting to form-up for the fifth floor,” Fitzpatrick said. “

We expect to have completed the core by about April.”

Next on the contractor’s to-do list is the completion of the interior work on the original building, installing new windows and refurbishing old ones.

Fitzpatrick said the main challenge on the project has been the lack of room to move around in.

“There’s limited access to the site because of the downtown location,” he said. “

And, it was a real challenge to work underground in such a tight space to construct the footings. All we could fit in was a small Bobcat excavator.”

ROBERT LESHGOLD / RELIANCE PROPERTIES

Workers on the site are getting material for the cast-in-place addition to the brick and beam structure that was built in 1909.

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