January 6, 2012

PHB GROUP INC.

An aerial view of the 351 Water St. development in St. John’s N.L. This building is projected to be the first one in Newfoundland to use seawater for its heating and cooling systems. Plans call for a six-level, 446 car parking garage and six storeys of offices.

St. John’s office project to use seawater

SAUL CHERNOS

correspondent

A 12-storey tower in St. John’s, N.L. stands to be the first building in that Atlantic Canada province to use seawater for heating and cooling.

The building, under construction at 351 Water St., will bear the same name and will overlook St. John’s picturesque harbour. Plans call for a six-level, 446-car parking garage, six storeys of offices, and a street-facing restaurant and retail area.

The 165,000-square-foot tower was first proposed by East Port Properties, a Halifax-based developer, in February 2010. Around that time, city politicians had exempted the waterfront area from heritage zoning restrictions in order to promote slightly taller, higher-density buildings than the downtown had seen to date.

The site has a history of commercial use extending back more than a century. Strat Barrett, the project architect and principal at PHB Group in St. John’s, says the most recent occupant, a Woolworths department store, closed roughly 30 years ago and the property has sat vacant ever since.

“The site hadn’t been used in a long time and was a bit of an eyesore,” Barrett says.

There’s been a rise in demand for office space downtown, so the site was considered ideal for a new development on the west end of the downtown core.

“It’s on the fringe, just outside other old historical buildings downtown that have been maintained, so it was well presented to add some height,” Barrett says.

An initial proposal called for two storeys of parking and five storeys of office space. But with the expectation that the nearby St. John’s Convention Centre will eventually be expanded, and with parking already tight downtown, the city asked the developer to consider additional parking.

The restaurant and retail space came about in response to a city planning mandate that calls for this kind of frontage on Water Street, which is one block from the harbour.

Furthermore, because the city wanted to maintain a 15-metre height along Water Street, the parking garage rises to that height but the office tower is set further back.

Construction started this past summer and the project is vying for Gold under the Canada Green Building Council’s Leadership in Energy and Environmental Design (LEED) certification program.

Plans call for a green roof atop the inset, where the top of the garage meets the office tower. The garden will feature close to a dozen grass and flower species considered hardy enough to thrive in Newfoundland, selected by Gerhard Weiland, the landscape architect.

“We don’t have a long growing season, so you have to be careful which plant types you use,” Barrett says, adding that the green roof stands to minimize the amount of water that ends up as stormwater runoff.

The project team also hopes its LEED ambitions will be helped by already-successful efforts to take rubble from the poured concrete building that was on the site and re-use it elsewhere as structural fill.

What makes the project stand out, however, is a geothermal system that will use seawater from the harbour to heat and cool the building. The building is so close to the water’s edge that crews will drill wells and install pipes directly underneath.

Because seawater is salty, mechanical parts and pipes that come into regular contact with it will be made of stainless steel and plastic to help prevent corrosion, Barrett adds.

Yet another construction challenge is decidedly geometric in nature. The parking garage is made of precast concrete, so the building team will need to get the slopes of the floor just right in order to accommodate the ground-level commercial space and ensure a proper fit with the upper-level steel-frame tower.

“The site has an angle on one side, and we have some steel going into the precast, so all the heights needed to be worked out,” Barrett explains. “It will be a challenge to get all of this to work, and we’ll do it by finessing the heights of the structure and aligning the structural components.”

Crews also hope to gain recognition for brownfield clean-up. Crews isolated soil contaminated by an old oil tank and hauled it off for treatment and disposal.

The project team includes, as of press time, architect Strat Barrett, PHB Group, St. John’s; developer East Port Properties, Halifax; construction manager Chris Voisey, Trendex Construction; Toronto, structural contractor Lindsay Construction, Dartmouth, N.S.; and landscape architect Gerhard Weiland, Tract Consulting, St. John’s.

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