Structural Glass Stair

A new glass stair, designed and built by my two affiliated firms, Thomas Roszak Architecture and Steelgrass, replaces an existing basic wood stair in a 39^th and 40^th floor penthouse residence. The glass is used as the primary structural material and only stainless steel is used for connection clips. The new glass stair allows light to pour deep into the home and creates a calming void in the space. The stair is so transparent, thanks to low iron glass, that it literally appears invisible and only a figure ascending or descending reaffirms the steps. The beautiful new building that the residence is contained in has floor to ceiling glass and exposed concrete, with simple and smart details throughout. It was only appropriate to insert an equally stunning installation with the same care for detail as the bigger architecture did. The city officials required public loads to be withstood on this residential stair and vigorous testing to be done on the glass mockup before a permit would be issued. The elegance of the thin glass and the few stainless buttons defy the fact that each tread can take up to 6,000 pounds before only the bottom third layer shatters. Sowlat was the structural engineer on our team. Rareform was the fabricator. The acid etch on the treads allows for minimum traction and just enough modesty. An open wine room is positioned next to the stair offering a unique view of the stair. The glass assembly of both tread and wall includes 3 layers of ½” tempered glass with an PVB interlayer and hinge-like connector under tread and at concrete opening to allow for rotation or vertical movement of up to one inch. The team of material suppliers were chosen based on their corporate ecological plan. The stair was studied as an object of art and one to be inserted into an existing space, it looks a little foreign, purposely an after-thought, better than the first.