Curtainwall or Storefront?

by Stacy Rinella | August 20, 2023 2:29 pm

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Storefront and curtainwall provide daylighting and views, and are composed predominantly of extruded aluminum framing and insulating glass units. Beyond these similarities, each system has different applications, installation methods and performance considerations.

Curtainwall spans multiple floors, often starting at the first floor, and may extend up several floors. Curtainwall frequently will be attached to, and extend beyond, the face and floor slabs of the building. The vertical mullions are anchored to the building structure. Horizontal mullions are not typically anchored. Curtainwall also offers longer spans and wider spacing between vertical mullions than storefront.

Storefront systems are intended to be single span structures. Most storefront systems are designed as flush glaze with no projecting stops, giving it a clean look. The anchors are at the head and sill only; not at the mid-span. The frames are installed between and anchored to the building structure.

Storefront frames are stick built from extrusion, and may be fabricated in the shop or in the field as needed. Pre-fabricated ladder frames can be brought to the site and assembled into the openings. This reduces the amount of field labor required for a job, which helps to keep costs relatively low.

Curtainwall presents a greater range of fabrication and installation options. In addition to the stick-built and ladder-assembly construction, curtainwall may be fabricated, pre-assembled and glazed in the shop. This ensures performance requirements are not subject to uncontrolled conditions in the field. Once at the jobsite, each unit is crane-hoisted into place to quickly enclose high-rise buildings. For buildings where exterior access is limited, inside-glazed systems can be specified and manufactured for installation from the interior.

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The key difference between storefront and curtainwall is the way water is managed in the system. In curtainwall, each lite of glass is weeped separately. In a storefront system, the entire elevation is weeped at the sill. Any water entering the system is directed down the vertical mullion to the sill, where it is then weeped to the exterior of the building. Consequently, this can lead to the system becoming overloaded when the exposure to weather becomes excessive. For this reason, storefront typically is limited in height. Ideally, it should be located second floor and below on a building in areas that are protected from weather elements by an overhang of the roof or other overhead structure. The more protected storefront is from the elements, the better it will perform.

Where thermal performance is important, manufacturers thermally break the aluminum framing. Interior and exterior frames are separated by an insulating thermal barrier. For additional solar heat management and daylight control, exterior sun shades can be attached. Operable vents and windows can be integrated within storefront or curtainwall to allow natural ventilation.

Storefront is often desirable because of its overall lower installed cost but is limited in performance and to low-rise installations. Curtainwall is considered the optimal choice when performance is of foremost concern, for longer spans and for buildings
taller buildings.

Steven Gille is pre-construction manager at Tubelite Inc. in Walker, Mich. For more information, visit www.tubeliteinc.com. Photos courtesy Seguin Gazette and Tubelite.

Source URL: https://www.metalarchitecture.com/products/curtainwall-or-storefront/

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