The harmony of the transparency of glass facades and roofs is often disturbed by clearly visible, opaque spacers. sedak’s glass spacer allows for insulating glass units with minimal joints. Photo: sedak GmbH & Co. KG

A glass spacer may seem like an unusual request, but when architects ask for innovation sedak responds by pushing the limits. sedak, a manufacturer of oversized insulating and safety glazing based in Gersthofen, Germany, has developed a glass spacer for insulating glass units (IGUs).

Glass spacers were made 25 years ago by a different company and used in a few projects in Europe. According to sedak general manager and sales director Ulrich Theisen, an architectural office in Switzerland asked sedak to develop a new glass spacer to replace the old ones in failed IGUs in those projects. The spacer can be used in the vertical (visible) glass edges and corners of IGUs to provide a transparent appearance. A traditional spacer would be used for the horizontal edges, which would include the desiccant to maintain a dry atmosphere within the cavity. Theisen says the glass spacer is ideal for high-value projects in entrance areas or viewing areas in residential buildings.

A challenge in creating the glass spacer was finding a transparent way to connect the glass spacer to the in interior surfaces of the inner and outer lites.

“If you glue glass to glass most of the time … you have bubbles or air inclusions. In this system it’s nearly invisible,” says Theisen. “It looks like it’s glass, glass and glass.”

Theisen says that the glass spacer could be less energy efficient than traditional thermoplastic spacers which have a higher U-value, but that low-E performance coatings and argon gas fill within the IGU make the unit with glass spacers comparable to traditional IGUs. Testing is conducted on all IGUs, with either glass or traditional spacers, by an engineer’s office to ensure the units meet the windload and strength requirements.

But a glass spacer won’t likely be a mainstream product any time soon. As Theisen explains, “It will not be part of the standard buildings for offices.”

He believes architects will be interested in the opportunity to use a glass spacer in an IGU because he says it offers architectural freedom.