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VS-1 Glass Wall and Façade System


VS-1 uses a blade-shaped mullion and cast aluminium fittings to support the insulating or monolithic glass. This simple kit of parts offers users an unprecedented level of flexibility while eliminating transoms and fitting hardware from daylight openings. VS-1 was created for designers, enabling them to provide new architectural responses, achieve superior building performance and faster project delivery at a great value.

Working with its partners, THERMOSPAN is an official and approved designer and installer of the VS-1 system.

Benefits and Features

• Long spans and large glass sizes
• Elimination of horizontals
• All-glass corners
• Mullion shape flexibility
• Point supported glass
• Increased design flexibility and ability to build complex geometries including curved glass and faceted glass
• Approaching zero sight-line windows
• Support for solar and intelligent façade systems
• Sustainability
• Cost-effective

External and Internal Views

VS1 wall detail 1
VS1 wall detail 2

System Assembly

VS1 system assembly

Fixing Details

VS1 fixing detail 1
VS1 fixing detail 2
VS1 fixing detail 3
VS1 fixing detail 4


Franz Safford, an architectural engineer, invented the VS-1 system in 2005 and was patented in 2015. It was a response to what Franz observed as a profound need to improve building envelope performance and better meeting the demands of architectural aesthetics and creative variation of the basic curtain wall.

Standard 70-year-old curtain wall technology remains largely unchanged and demonstrably unable to respond readily to the modern visions of architects and their clients. Franz saw the opportunity to evolve the technology and better meet these new demands with a new system.

Franz took a significant step forward by combining his knowledge of lattice structure (space frames), integrated wall systems, tension structures and all-glass assemblies using glass as the primary structural load-bearing system. It broke through the stagnant, stale concepts of the 1950s that have stunted innovation in curtain wall design.

No longer are curtain wall design details and performance attributes too expensive and unrealistic for large fa├žade applications. This breakthrough enables designers to enact a level of detail that was previously too expensive or too complex. In its short history, VS-1 has already achieved that goal and begun to transform the curtain wall industry at exceptional value to the building owners.

Example VS-1 Projects