Tall Buildings, Complex Glass Impact Installation

By Jordan Scott

Increasingly tall buildings, complex glass systems and larger glass sizes are not only trends within the commercial sector; architects are also adopting these features for residential high-rises, which makes installation more complicated due to the added weight and logistical challenges.

Both glaziers and systems’ manufacturers must adapt to ensure the safety of both those
on the jobsite during installation and the residents of these tall buildings once completed. A lack of proper installation practices could cause harm to the glaziers or lead to failed glazing systems that put residents and people on the streets below in danger.

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With new trends comes the need for change. As new developments emerge, glazing contractors and suppliers have to re-evaluate how glass and glazing systems are designed, handled and installed for the safety of everyone involved.

Oversized glass is a growing trend in both the commercial and residential sectors. However, working with large glass lites also brings unique installation and logistic considerations. For example, jumbo glass sizes may not be able to fit in elevators or up stairways easily.

“You need to coordinate more cranes and more exterior methods of getting things up, so more permits are needed [than when handling smaller lites]. You also need to deal with the fact that larger glass is backordered more often,” says Greg Header, president and CEO of Solar Innovations in Pine Grove, Pa.

“Quality standards on large glass are a little bit more relaxed and most customers don’t want to compromise on the quality of their glass. There’s a lot of gray areas when it comes to imperfections in oversized glass. With the cost of replacing and handling it you now need more mechanized equipment to physically handle the glass and get it in place.”

Joe Pecorino, owner of Pro-Installation based in Franklin, Tenn., says that with heavier and more complex systems, glaziers find themselves coordinating with the other trades on the jobsite more, such as coordinating the use of cranes to hoist material. He expects that glazing contractors will have to invest in new technology to keep up with the demand for heavier glass.

“They have technology with motorized suction vehicles that are robotic … we’ve started to get into larger and larger glass panels, so that’s going to be our next option … to consider the more expensive material handling for glass,” he says.

“Also, oversized glass breaks as easily, or even more easily, than smaller glass because if you touch it against something you have more force in motion. It’s a heavier weight so there’s less room for error,” says Header.

The Pre-Glazing Rise

Unitized systems are also being used more frequently and can also mean heavier, more challenging installations. According to Greg Galloway, ProTek brand manager for YKK
AP America Inc. based in Austell, Ga., once glaziers move from a stick-built system, where everything is assembled onsite, to unitized or pre-glazed systems, the units become heavier and require a lifting device.

“… When you’re assembling onsite you can use glass cups and the lifting equivalent is attaching to the glass itself. When you’re using a fully assembled unit you have to
be very careful that if you pick it up by the glass that you’re not breaking the seals of the glass’s sealed frame,” he adds.

The use of pre-glazing and unitized glass systems is increasing for a number of reasons, including the efficiency and safety provided compared to stick-built systems.

“I don’t know the exact mix but I’d say more [buildings] need to be pre-glazed now rather than built onsite for a number of reasons, many of which relate to the construction cycle. You can get in and out [of the jobsite] quicker to close
in portions of the building faster,” says Galloway.

Glazing contractors such as Zinsel Glass in Terrytown, La., have also begun to prefer unitized systems.

“It makes it a safer install overall and also makes it quicker. YKK has an inside glazed, pre-glazable window wall which allows us to do all glazing in the shop and will actually allow us, in the current project we’re doing, to put all muntins on the glass in shop prior to bringing the window in the field which should be a real cost and time saver for us,” says Jay Dunnell, senior estimator at Zinsel Glass. “New Orleans is an old city, so they like muntins; instead of big sheets of glass they prefer small pieces. This system is going to allow us to put muntins on the glass, install it in the field, and then only have to caulk from the outside of the exterior joints. So it’s a real time saver for us.”

Minimal Sightlines

Architects often prefer narrower sightlines. As a result, zero-sightline vents are another trend.

“Those simply have a frame that mounts inside the curtainwall or window wall and then the glass is four-sided structural silicone-glazed, so from the exterior of the building, if the vent’s closed, you don’t see it,” says Galloway. “Architects love it for a number of reasons. … [One example], especially for multi-family residential, is you may have a window opening that is four units wide (12 feet wide by 7 feet tall) and they want a window in the middle of it. One traditional way of doing that is to have a combination of
fixed and venting windows to fill that opening. Going with either window wall or curtainwall with a zero-sightline vent in the middle uses much less aluminum, meaning smaller sightlines and less cost. Architects love that also.”

According to Dunnell, the majority of projects in which his company is involved include operable vents.

“We use a lot of operable vents which are typically structural silicone glazed so they don’t stick out beyond the actual framing of the window wall and are self-concealed,” he says.

Use of four-sided structural silicone glazing is a trend Galloway has noticed in residential curtainwall installation. He says unitized or fully assembled units ready to be
installed on the jobsite are becoming more common, and most unitized curtainwall systems are four-sided structural silicone.

“When you’re talking about unitized curtainwall it’s much more complex to have a mechanically fastened face cover on the units because you end up with a dual cap look,” says Galloway. “If you have a face cover that is functionally holding the glass in place on a discreet unit, then the unit next to that also has to have that and you have a gap between the two. That can be a look all to itself, but it’s not a very popular look. It’s just
cleaner and easier to make it as a unitized unit and attach an aesthetic face cover to one side that just slides over the glass of the adjacent unit to give you the captured look.”

Cause for Collaboration

In many cases, contract glaziers aren’t brought onto a project until the later stages and are left to fi gure out the logistics of what’s been handed to them. Header suggests
that glazing companies should develop systems for working with other project leaders.

“I still think the coordination could improve … A lot of the glaziers retired in 2008 during the construction industry downturn,” he says. “Now we are faced with a bit of a
labor and skills shortage. The continued retirement of those senior people is creating a skills gap and more of a turnover in the industry that really creates even more challenges. ”

Dunnell says that Zinsel Glass often is brought on early enough to recommend systems.

“Contractors are trying to be more efficient when it comes to jobsites … [For one project with zero laydown] we’re trying to get the material onsite just as it’s needed,
instead of dumping material everywhere,” he says. “We’re working with them to lay out a time schedule to do that, but also a method of installing that allows four different trades on the building simultaneously on the exterior.”

Residential high-rise construction is growing more complex, but the process is also becoming more efficient thanks to unitized glazing and modern technology that allows glazing contractors to overcome these challenges.

Project Spotlight: Making Curtainwall Residential

A three-story curtainwall and metal claddings fabricated by Gamco Corp. of Flushing, N.Y., are focal points of a new upscale private residents in Queens, N.Y.

For the Astoria residence, Gamco’s CW250 2-½-inch aluminum product was used for the building’s curtainwall framing. With 2-1/2-inch by 3-7/8inch back member profiles, the framing features a 1-inch thick glazing pocket for insulating glass units and spandrel panels. The curtainwall system is more than 28-feet tall, spans three levels of the residence and is approximately 25-feet wide.

The curtainwall system was mated with three two-panel aluminum sliding doors supplied by Crystal Window & Door Systems, also based in Flushing, N.Y.

Gamco fabricated custom three-story tall, 1/8-inch thick aluminum covers to clad the building’s vertical structural steel columns.

In addition to sliding patio doors, Crystal Windows also supplied fixed picture and sliding windows. Vitro SB70 glass was used in the various tempered insulating glass units fabricated by both Oldcastle BuildingEnvelope® and Tempco Glass Fabrication. Mike the Glazier provided the fenestration and architectural metal installation services. The project architect was Gerald J. Caliendo.

Jordan Scott is the assistant editor of USGlass magazine. She can be reached at jscott@glass.com.

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