Retail leasing giant RioCan aims to re-invent 20 of its old, tired malls in major Canadian cities by putting up high-rise towers with apartments, offices and ground-floor stores in a bid to deal with changing retail trends.

The country's largest real estate investment trust held an open house for Ottawa residents on Wednesday evening to lay out a proposal for Westgate Shopping Centre, which it intends to submit to city planners in January.

The early designs show five towers to be built over the next decade or two, bringing 1,100 residential units to the site of one of the city's oldest malls. The first towers on Carling Avenue could be 24 storeys, while the ones closer to the Queensway could be 36 storeys.

"Retail's changing. A lot of people are shopping online. You can get groceries even by picking up the phone now," said Stuart Craig, RioCan's vice-president of planning and development.

"The one thing retailers have been saying to us across the country — and we have 340 centres so we talk to a lot of retailers — is you've got to bring more customers to our doorsteps."

Company has plans for Elmvale Acres, Silver City Gloucester

Craig sees RioCan putting in green space where he right now sees a "sea of asphalt." The site is attractive partly because the city intends to improve transit in the area in the next 15 years, he said.

The goal, Craig said, is to re-invent good properties to make sure the company's real estate assets are used well and viable. RioCan is introducing residential as a way to strengthen its retail, he added.

At Westgate Shopping Centre alone, Craig said RioCan plans to invest more than $200 million.

The company held a public meeting recently about a similar long-term plan for Elmvale Acres Shopping Centre on Ottawa's St. Laurent Boulevard, and it also has plans to build three towers at a strip of mostly empty stores at Silver City Gloucester.

The company may eventually look at Lincoln Fields and Donald Plaza.

In addition to those projects to intensify shopping sites in Ottawa, Craig said RioCan is considering others across the country: three in Calgary, one or two in Edmonton, two in Montreal and eight in the Greater Toronto Area.

"It's a huge capital expenditure, ultimately, but we're a fairly well-heeled company so we're prepared to take on the challenge," said Craig, who admitted RioCan's strategy is a "big gamble."

"I'll be honest; if we do one or two of these and they bomb, then the program will be shut down and instead of doing 20 across the country we'll only do a couple. But we're fairly optimistic that won't happen and we think there's a demand in the larger markets."

Residents who studied how Westgate Shopping Centre's site could look in the future worried about keeping their amenities, living through years of construction and available transit.

"It's a good idea to have maybe a grocery store in there and really get business going. It will be good for the community," said Risa Upton, who lives nearby and regularly uses the traditional mall with its long hallway and shops.

"But then it will be sad, because people won't be able to hang out there."