Curtain rising on glass walls

[Guest guest]

BUILDING TECHNOLOGY

Curtain rising on glass walls

High-profile projects are trading concrete walls for massive windows

thanks to `curtain-wall' technology

Toronto Star - Ontario, Canada*

Dec 01, 2007 04:30 AM

Weir

Special to the Star

http://www.thestar.com/living/article/280592

Is the curtain set to come down on the traditional, aluminum-framed

condo window? Is a new industrial style about to eliminate

condominium owners' two biggest pains in the glass – moisture and

mould?

Toronto is about to find out as several highrise project designers

have decided that ultra-expensive curtain wall glass is the chic way

to let light in and keep water out.

Windows come in many tints, shapes and sizes but almost all are

installed using what builders call a window wall system: Glass goes

into an aluminum frame which, in turn, is attached to the inside of

a building's outer walls. Although relatively cheap to build, mount

and repair, a poorly installed window wall can allow damaging

moisture into a condo unit.

For residential projects where money is not a significant concern,

floor-to-ceiling suite windows appear ready to make concrete outer

walls obsolete.

Four soon-to-be-built projects – the Residences at the Ritz-Carlton,

the Yann Weymouth-designed 77 St. West project, The Florian

and the Four Seasons Residences in Yorkville– will hang their

windows onto the frames of their buildings using an industrial glass

system known as the curtain wall.

" Up to this point, almost every condo in the city has used some form

of the tried-and-true window wall, " says Darius Rybak, the project

manager for 77 St. West. " But when you look at the office

towers in Toronto's downtown core, you see that glass is everything.

Those 10- and 12-foot-tall windows look strikingly different than

what you get in a condo residence. That is because the office towers

don't put their windows inside a wall, they use glass to become the

wall ... hence the term curtain-wall system. We are taking that

industrial concept and using it in our next downtown project. "

The 77 St. condos, designed by architect Weymouth who made a

name for himself designing the Paris Louvre's glass pyramid, are an

artsy venture in waiting. Once the existing four-storey Lycée

Français private school has been shut down and the site cleared,

Rybak will oversee the construction of the 16-storey multi-use

structure for Aspen Ridge Homes.

At street level, the new building will blend in with the University

of Toronto neighbourhood. The first three floors are limestone, with

understated doors and traditional windows. This will be home to

Kintore College, a small religious residence and educational centre.

On top of this heavy-looking structure will be a stacked, seemingly

transparent 13-storey all-glass tower. The condos inside will range

from 1,200-square-feet lower-level suites, to 6,000-square-feet

penthouse units. No price has been announced for the top floor, but

the rest range from a reported $1.2 million to $6 million.

This will be a radically different-looking glass-wrapped condo in a

part of Toronto where windows are making an exotic statement. Just a

half a block away is Libeskind's controversial Crystal at the

Royal Ontario Museum.

" Our curtain wall will use large sections of glass which will give

total vision to each floor, " Rybak says. " The individual units of

glass will be five-feet-wide by four-feet-high. The suites we have

are 10 feet from floor to ceiling, while the penthouse will have 12-

foot ceilings. "

Because the glass is not supporting any weight (aside from its own

dead load) the height and width of the glass is considerably larger

than traditional windows.

" This type of system is probably about three times more expensive

than a window wall. The thing is we aren't making more money on

this – we are providing a high-end product – we call it our jewel. "

Ignoring the cost of the curtain wall, the system will save money

for homeowners over time. It is designed to block air and water from

being pushed inside by heavy winds. It also puts a stop to outward

air leakage, saving on heating and cooling costs.

" Water, be it windblown rain or snow, can get into a suite through

the window. It could take years, but when there is moisture behind

drywall the danger of mould is real, " says Tucker, director

of construction for Graywood Developments Ltd, the company building

the 53-storey Residence of the Ritz-Carlton. " From a practical

sense, a curtain wall eliminates the worry of warranty claims that

other buildings face because of mould and moisture damage. "

Window-washing firms are probably already in an advanced frenzied

stage of salvation as they impatiently wait for the new Ritz-Carlton

hotel and condominium tower on Wellington St. (kitty-corner from Roy

Thomson Hall) to be completed. The structure will use a curtain wall

system that might, at first glance, make one think of a giant

terrarium turned on its side.

" The benefit of the curtain wall is that the residents and hotel

guests get a superior product, " Tucker says. " We won't start hanging

the windows until well on in the building process, but once we start

the glass will go on rather quickly – I think we can do a floor a

day. "

The Ritz is working with Sota Glass in Brampton. The company, owned

by Speck, designs and exports the Canadian-designed curtain

walls to large-scale projects worldwide. Most of the customers are

builders of large office towers, but already in other cities

developers are finding that the market for high-end condos will bear

the added cost of the curtain wall.

" There isn't (an) off-the-rack curtain wall. They have to be custom-

built to take into account (the shape and slope of the building) "

Tucker says. " We will, of course, order extras in case of breakage. "

Earlier reports said the Ritz-Carlton would use a tinted glass. That

apparently is not the case; the hotel and condo is going au natural.

" Tinted windows are so very much a look of the '90s, " Tucker

says. " Even a slight colour clouds the view. The Ritz-Carlton will

be installing haze-free, crystal-clear glass. "

Living hundreds of feet above the city with only two sheets of glass

between you and the pavement, does one have to worry about

accidentally banging into a window and falling out?

" This is tough glass, similar to what is already in place at the new

Four Seasons (Centre for the Performing Arts) opera house. It might

be transparent, but it is double-paned and industrial strength. (It

is built to withstand gale-force winds.), " Tucker says.

Of greater concern for many, likely, will be getting used to living

in a glass home. Standing in front of a window that doesn't even

appear to be there, 40 storeys above a city that never sleeps, may

make condo owners feel on display. But that is why designers

invented curtains in the first place.

[Guest guest]

I used to know some people who used this electric LCD glass to enclose

their bathroom. When someone went in, the glass turned opaque, and

nobody could see in, then when they walked out, it became clear again.

That was a very neat effect.