A quest for thick glazed façades

After decades of glass thickness reduction and transparency in glazed façades, a whirl of glass translucency and weight is taking the architectural scene. You may have found it already in small places: building entrances, sculptures and the like. But the quest for thick, icy blocks of glass stacked in façades is here to stay, or at least that's my impression.

This post will discuss origins and directions of the 'thick glass' trend.

GE Building glazed entrance detail, seen from inside. Designed by Lee Lowry, 1933-34

Inspiration for this story came by chance during a visit to New York City some months ago. The main building at Rockefeller Center - RCA tower, now called GE Building - has a decorated main entrance finished in 1934 that called my attention. The top part of the entrance shows three stone low-relief panels conmemorating the spirit of the radio, named "Wisdom, Sound and Light" (see image below).

Sculpted by Lee Lawrie, the imposing central panel showing a bearded Wisdom figure, today an art deco icon, can be clearly seen from Fifth Avenue. But the top limestone pieces are only part of the story.

GE Building entrance at the Rockefeller Center - stone and glass low-relief by Lee Lawrie, 1933-34. You can identify Wisdom at the top centre, Sound at the left and Light at the right hand.

With golden rays crowning his head, Wisdom's right hand clutches a golden compass that measures the cosmic forces swirling in the 15 x 55 feet glass blocks screen below. Here comes the magic. Made of 240 glass blocks carved in cast Pyrex, the screen is a technical and artistic masterpiece.

Piccirilli's "Youth leadind Industry" at 636 5th Ave

The glazed bas-relief is a translucent wall of rectangular glass pieces (around 700 x 450 mm each), tied at their back to vertical bronce stripes, with a delicate front texture: calmed at the edges of the screen, agitated in the central axis below the moving compass. The attached images (see below) provide a pale impression of its contrasts: thick but slender, translucent from inside but almost opaque from outside, half part of a door and half part of a sculpture. 

Lee Lawrie was not the only artist using cast glass at the Rockefeller Center in the thirties. If you compare Lawrie's magnificent glazed entrance with Attilio Piccirilli's "Youth leading Industry" (see at left, finished in 1936) the contrast is clear. Piccirilli's glass low relief adorns the entrance of the International Building at 636 Fifth Avenue. Lit from behind but opaque if seen from the inside hall, it remains an evening spectacle on Fifth Ave. Piccirilli's bas-relief was cast in 45 Pyrex glass blocks, each hand-cast and different.

Good enough, but we will probably agree that Piccirilli's screen is merely decoration, not architecture. Glass here could have been marble and it would remain rather similar. That is not the case with Lawrie's screen, where glass and transparency go hand in hand as the following images taken from inside testify. 



Top to bottom: details of the glazed wall at the Rockefeller GE Building entrance. All taken from inside except the bottom right one.

 Seen from today Lawrie's glazed entrance is strikingly modern. In fact, a number of translucent massive facades could be linked to the images above. One of them, of course, is Rafael Moneo's Kursaal Auditorium in San Sebastian.

The Kursaal Auditorium is the combination of two translucent, twisted and slightly angled glass cubes located by the seaside - two 'stranded rocks which perpetuate the geography and underline the harmony between the natural and the artificial'. The cubes have curved laminated glass walls which protect them from salt-laden sea winds. The outer skin, a laminated 19 mm extra-clear, sandblasted glass with an external 5 mm fluted printed glass, transmits light to the interior by day; at night the exterior is transformed into a mysterious light source. 

Kursaal San Sebastian (Rafael Moneo, 1990-1999). Main Auditorium building looking outside through one of the big windows.

I like the view from inside the cubes (see above) because it explains the building concept better than the typical daylight external images. Of course there are differences with the GE building entrance. First in scale, then in layers: the Kursaal façade is a double skin wrapping the steel structure of the buildings. The outer skin is curved and fluted, the inner skin is flat. Both are slightly translucent to avoid direct vision of the encased steel structure.

Kursaal San Sebastian. The curved glass facade.

But there are a number of surprising similarities too. In both cases the glass grid is rectangular and horizontal, with continuous vertical joints - a stacked bond. The intention is not to read the facade as heavy masonry but as a light screen. Then the curvature: concave at the outside, flat at the inside. And finally the fixing system: a slender line of mullions from behind in both cases. Even the yellow light coming in is strikingly similar!

The images of the Kursaal facade during construction (see below) are as always very instructive. Isn't this Lawrie at a gigantic scale?

While I was working for Cupples - around 1992-93 - we visited Rafael Moneo at his studio in Madrid for this project. He was rightly obsessed with the quality of fluted glass he was looking after, and with the availability of suppliers for such a combination of fluting, lamination, extra-clarity, translucency and bending in glass. Cupples presented Moneo several glass samples and we prepared some façade details. The story moved on and finally Cricursa supplied the glass. The façade contractor was the Basque group Umaran, like Cupples a great but extinct dynosaur from the 20th century.

Kursaal San Sebastian. Images of the double skin façade during construction.

But Moneo's Kursaal use of glass is also an example of relative failure in translucency. Depending on the time of day and the sun position the structure behind the outer glass may become too obvious. In these occasions the visual impression is not of an ice block but of a thin veil: the game of scale is lost and the building fabric becomes too evident. The image below is one of those cases.

Thick glass can be more subtle and difficult to control that sheer transparency... but then, when is glass really transparent?

Kursaal San Sebastian. Aluminium mullions and main structure appear behind translucent glass as seen from outside.

Let's go back to New York in our quest for iced glass blocks. 11 Times Square is a new office tower (opened in 2011) located right beside Renzo Piano's New York Times building. Waiting for the green light at 8th Ave with 41st Street I was surprised by the contrast between a tall, thin, mullion glass-supported transparent wall and a back-lit stacked glass wall beside. Both are part of the main lobby of this tower.

11 Times Square lobby seen from 41st Street, NYC. FXFowle Architects LLP.

If you came from a time travel - right from the seventies for instance - you would be surprised by the height of this transparent glass wall, standing still without any apparent aluminium or steel support. And it's really impressive, even today! But after the last two decades of structural glass walls we are used to see large glazed walls supported by glass fins with bolted stainless steel spiders as the only connecting points.

What called my attention in this case was the yellow glass wall to the left of the lobby: a back-lit translucent wall made with flat, vertically fluted glass blocks, stacked to provide a screen to support the building name and its tenants. It reminds us the facade of the Kursaal or Lawrie's cast glass, except that this one is opaque and flat. A detailed view can give us more clues. The whole glass lobby was commisioned to Gartner Steel and Glass, part of Permasteelisa Group, and completed in 2010.

The transparent part has a surface of 1,040 m2. The glass fins project out of the glass plan into the walkway and are 16.4 m in height, helped by an intermediate connection at a back slab located at 2/3 of their total height. The special stacked glass wall - this is all I found at Gartner's webpage - is 120 m2.

11 Times Square stacked glass wall at the lobby. Images from outside (left) and inside (right).

A detailed view will give us more information about our next icy translucent wall. It must be a laminated glass with the outer lite cast in vertical stripes. The thickness of the stripes is wider than the one at the Kursaal, but its flatness provides an impression of subtle weaving. As in San Sebastian the glass is retained by a grill of parallel, horizontal profiles: here they are in stainless steel, those at the Kursaal are made in cast aluminium. What a decision of a master builder: cast aluminium supporting cast glass!

The stacked glass wall makes itself apparent in the evenings, when crowds rushing to attend Broadway plays mix with those running home from work. At this time the 'eleven' mark behind the glass becomes obvious and the tenants' names shine in darkness against the back-lit wall. Sadly, this is a sign of our times: gone are Wisdom and his colleagues; what matters now is company brand image...

11 Times Square tower. General image (left) and lobby from inside (right). The stacked glass is a screen supporting tenants' logos.

The list of recent 'thick glass' walls is endless and this post cannot be that long. From the examples above we have got a fair view of stacked, heavy laminated glass, but this is only one technique in many.

Let me list other techniques that are being used to obtain the impression - or the literality - of thick glass (some of the buildings listed here are shown right below):

1. Fused glass. A supplier of this technology is Fusion Glass Designs, a brand of the British company Chelsea Artisans. One of their recent jobs is the Louis Vuitton shop in Singapore, with kiln formed, curved and laminated glass. You can also look at this webpage for more info.
2. Molten cast glass. This is the way U-glass (or channel glass) panels are made. The European main name in this technique is the German firm Lamberts, with the brand name Linit, while its US counterpart (and business partner) is Bendheim Wall Systems. The exemplary building with a U-glass cast facade is of course the Bloch Building at the Nelson-Atkins Museum of Art in Kansas City, a project of Steven Hall Architects finished in 2007.
3. Slumped cast glass. Also called warm glass or kiln forming, a supplier of this technology is the British firm Warm Glass.
4. Cast glass. The general term; many of the examples here are somehow made of glass cast in a mould. A well-known supplier is Castglass and one of their recent jobs, the Diesel store in NYC, with cast glass molding in LED lighting. Another façade to visit is their Glassworks Hot Shop in Louisville Kentucky.
5. Pattern glass. A general expression for laminated or printed glass where an intermediate layer or screen is added, creating the impression of pattern and providing translucency. A high-quality European supplier of this kind of glass is GlasMarte from Austria. They are the glass suppliers and façade contractors for Peter Zumthor's acclaimed translucent façade of the Kunsthaus in Bregenz. They also have an interesting glass point ceiling fitting system, named GM Kub. Worth having a look...
6. Recycled glass. A new technique. When glass pieces coming from recycling are fused the result is a greenish, opaque panel with a promising application to façades. For most cases a 20mm thickness provides the required strength. See more at the British supplier The Greenhouse Effect.
7. Other techniques, worth exploring if you are interested: glass billet, heavy laminated glass (the buildings presented above), carved glass, extruded rolled glass, textured glass...

The Louis Vuitton facade in Singapore. Kiln-formed, laminated and curved 8+8mm glass.

Nelson Atkins Museum of Art, Kansas. Steven Hall architects. U-glass facade from Lamberts - Bendheim.

Nelson Atkins Museum of Art; Steven Hall architects. Detail of the double skin facade with U-glass at the outer side.

Kunsthaus Bregenz, Peter Zumthor. Austria 1997. Etched translucent glass.

The Kunsthaus at dawn with back-lighting.

We are entering a different ground here, that of glass as an artistic expression. But don't be afraid. If 'thick glass' in its many forms shall remain a trend for contemporary façades, there must be artists out there, chaps comparable to Lee Lawrie, from whose work we could get inspiration. You can find many names in this useful link provided by Lamberts. But if you wanted to meet only one name that must be Danny Lane, the best one to finish this post, an invitation to the artistic glass world.

Danny Lane posing at his studio in London.

Danny Lane (born in 1955) is an American glass sculptor living and working in the UK. Lane’s work is monumental as much as physical; his stacked and fractured glass walls are in a transition zone between scupture and architecture. His London studio is equipped to create works of considerable scale, in glass and in steel. Glass furnaces enable Lane to create works of fluidity and brilliant colour as the ones selected below.

Go and visit his webpage for more. Please click the Process tab: you will learn how these glazed, iced pieces were made.

Danny Lane, detail of stacked glass with a tensile rod.

Danny Lane, Presence of Seven. Allegheny College Pennsylvania USA (2002)

Danny Lane, Stairway. Borgholm Castle, Sweden (2005)

Danny Lane, Split Prism. San Francisco USA (2011)

Danny Lane, Borealis. General Motors HQ, Detroit USA (2005)

Danny Lane, Borealis detail. General Motors HQ, Detroit USA (2005)

Danny Lane, Ice. San Francisco USA (2011)

Is there materiality in glass? Plenty, as we have seen. Why then should we go only for the thin, transparent, ephemeral glass lites we have been using during the last century? Come on, cross the new frontier and be welcomed to the thick glass world...