Volume 45, Issue 5 - May 2010

feature

Framing Advances
Helping Architects Take a “Whole Window” Approach to Specs
by Megan Headley

With all the improvements being made in glass performance today, it can be easy to forget that the design and installation of framing can make or break the performance of a window or curtainwall system. After all, it’s through the framing connections that water and air can leak into a building, and the frame’s thermal conductivity is as integral a part of the unit’s thermal performance as the glass is.

“There’s a definite connection between the two—the glass helps the framing system too,” says Walt Lutzke, marketing coordinator of Tubelite Inc. in Walker, Mich.

Gary Taylor, marketing manager of the commercial products group of U.S. Aluminum in Waxahachie, Texas, elaborates, “The use of a proper framing system will improve the energy efficiency of the whole system, including the glass being used. The key to energy efficiency is thermally broken framing, installed properly, in an opening designed to accept the type of framing required to meet the surrounding conditions, using the correct glass make-up to achieve a desired U-value.”

Taylor adds, “Any system used, if not installed properly, can de-value the efficiency of the whole system.”

Greg Koch, sales manager for REHAU in Leesburg, Va., says that one of the challenges architects face when it comes to commercial door and window framing systems is that they simply aren’t aware of all of the new options available.

“I think that one of the challenges we have is to demonstrate to architects and the industry as a whole that we’ve moved beyond the late ‘60s, early ‘70s technology in glazing systems—basically, aluminum—and in trying to figure out how aluminum performance can be improved by adding thermal breaks, thermal slots, etc. There have been so many ways used in trying to improve the performance of aluminum,” Koch says.

 

Framing Trends
As suppliers and glaziers alike know well, architects have to look for aesthetics as well as performance in the products they specify. Frames are one area where the architect can be unique, as Lutzke points out. “Simple things help customize the project so it looks a little more unique—maybe a different profile for the face cap, or a new color of some kind,” he says.

Koch agrees that unique color is one option requested time and again, a request that he says has been an issue with PVC products, such as the curtainwall his company manufacturers, in the past.

“One of the challenges that’s always been associated with PVC is color options. You can create colors by laminating a high-performance film or adding paint to the surface of the PVC and there are systems that have been engineered to have success with that. But, again it’s something new and different and convincing everyone these are good options is a challenge,” Koch says.

Taylor, too, sees painted framing as a frequent request—particularly requests for custom colors—as well as minimal sightlines and larger spans. He also says architects and the owners they serve are, quite simply, “looking for a clean, durable, energy-efficient product that accents the whole building and allows as much visible light into the building without obstructing the view.”

 

What Architects Need to Know
When it comes to education for architects, these suppliers see a number of common errors come up time and again—errors that glaziers and fabricators should be aware of before they happen.

“The biggest [error] we see is knowing when to use curtainwall versus a storefront,” Lutzke says. “Even if the material is on the ground floor of a building it may be taller than the storefront product is designed for.”

“I wish that they knew that it existed,” Koch quips of the product his company offers. He adds in seriousness that this is, in fact, an issue—many designers may not look to the materials used in Europe as a basis for design. In reality, Europe has faced the energy costs that now are driving glazing trends in North America for many years.

“They’ve been faced with these energy costs for decades now and they needed to find a solution,” Koch says. He adds, “It’s an educational thing.”

In addition to awareness of the products available, Taylor says, “I would like to see architects consult with the system vendors when designing a project. A lot of designs miss a few pertinent issues” (see Tips for Proper Specs below).

 

Tips for Proper Specs
Gary Taylor, marketing manager of the commercial products group of United States Aluminum in Waxahachie, Texas, points to a few issues that he says designers frequently miss when it comes to properly specifying framing:

• The surrounding substrate may not be designed to handle the load or depth of a system required to meet the criteria.

• The way that a system is glazed during new construction does not always account for ease of glass replacement in the future. Taylor says he sees “inside set” systems that have a wall, cabinetry or some other obstacle installed in front of the framing, making it a “remodel” project should the glass need to be replaced.

• Expansion joints should never be under the threshold of entry doors, Taylor says. “Architects should design the building slab to continue past where the entry doors are to be set. The installer needs to have enough substrate (concrete) that his anchors will not ‘blow out’ when installed. The expansion joint needs to be far enough away from the threshold so as not to affect the operation of the door(s) due to heaving from freezing and thawing.”

• Caulking to EIFS needs to be done before the top coats are applied, otherwise proper adhesion will not occur, thus causing the window system to leak. “This, unfortunately, ends up falling back on the glazier and window manufacturer with the reasoning that their system is failing to stop water penetration,” Taylor says.

• Taylor points out that “realistic designs that are achievable” can be created with the input of a vendor’s representative. “This input will help to keep the job from stalling during the construction phase while a desired effect is being worked out,” he adds.

• Architects specifying custom-painted or -extruded systems should realize the time constraints of this design and make sure that it will work in the timeline by which the owner would like to have their building completed.

• Proper anchoring is paramount to preventing system failures. Taylor says, “Too many times I have seen storefront framing installed in 16-gauge metal studs without any blocking in the studs. There is usually a push, back and forth, between the general contractor and the glazier, as to whose responsibility it is to install that blocking. What I hear the most is, ‘it’s not shown on the drawings.’ The general contractor tells the contract glazier that it is their responsibility. The contract glazier tells the general contractor that it is the framer’s responsibility. It goes back and forth and becomes a major issue. A lot of times, blocking never gets installed and thus, the system is installed improperly. This ends up being a ‘time and material’ issue with regards to who is responsible, and who is going to pay for it.”

Megan Headley is the editor of USGlass.




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