Renovation projects often offer a kind of challenge and at the same time an opportunity to work with a previously existing design. 

In these kind of projects, as a designer one can respect and subtly alter the existing design without a very strong intervention. 

Or one may choose to completely disregard the existing and make a totally imposing new design to stamp one’s signature on the building. 

A third way is to do both, where the designer’s outstanding intervention actually respects and complements the existing design, whereby creating also a niche for oneself in contemporary times. 

This kind of design intervention is very successful in winning the appreciation of both the architects and the common public.

The Louvre Pyramid by I.M.Pei belongs to this type, where he chooses to put an iconic glass pyramid, in the front for the new entrance, which is transparent enough to not obstruct the existing renaissance architecture of the Louver palace.

UCCA was a renovation project for an Art Gallery with OMA as the architects.  

The reason for citing the Louvre Pyramid before is two-fold, one being a case as described before of the type of intervention involved, the other being even in this project the focus was the ‘entrance’ and how the building actually relates with the street.

In UCCA, the function of the building was an art gallery, the architects’ concept of showcasing glass façade as an art exhibit in itself was a fantastic idea.

Our scope was limited to the lobby and skylight. The project pushed the boundaries for what can be possible with glass as a façade element, geometrically and structurally.

UCCA, Beijing, OMA  

 2 FACADE DESIGN           

How does one imagine a glass façade as an art exhibit, exhibiting its imperfections, being organic as well as geometric in order to be reasonable? How does one panel connect to another seamlessly?

Sketch showing the façade flowing in and out of the building line

The glass façade was to flow in and out of the existing columns. The glass façade had to be seen as a seamless one, meaning avoiding any mullions in between.

Glass as a planar element is not strong enough to resist the wind without vertical supports for 4m spans, unless it’s super thick (like Apple stores). 

But the architectural concept of wrinkled façade and using the shape of the glass was beneficial for this, as once the glass is deformed, its inertia or ‘bending stiffness’ increases with the overall depth. 

This became the starting point to develop the façade.  There was quite a lot of freedom, with some constraints.

The first thoughts were：

1. to bend the glass along the edges ;

2. Do a bubble glass;

3.  Make ‘Rippled’ Glass.

We developed various options which could structurally be self-supporting for the span, by modifying the geometry of the glass in its depth, at the same time having discussions with manufacturers on what is the minimum curvature they could do. 

The final façade was optimized to be worked with five types of glass panels, with different combinations of placement next to one another.  

Final façade with five types of glass pannels 

Several suppliers were contacted to find who can produce such glasses. Normally when the quantity is large, many suppliers are willing to take the challenge as the risk of failed trials can be compensated within the repetitions involved. 

But in this project, the façade quantity was small, so few suppliers were willing to push their boundaries and experiment to get the design right. Luckily North Glass was willing to do it.

3   PRODUCTION   

North Glass factory visit was an eye opener in itself.        

Never had I seen 18m long glass stacked before! There were several other bespoke glass types in the factory. Normally it is more convincing to see if somebody is capable of achieving a bespoke complex design, if you see that they are really ambitious and quality conscious.

North Glass produced several glass samples which broke. In fact, North Glass made so many trials and broke so many glasses in the process, that I began to wonder at what moment they might withdraw from proceeding further. But seemed like every test was slightly better than the previous and they were confident of getting good results in the end. 

Bubbles within the laminated layer    

In the beginning, the problem was with the sharp curvature of the rippled glass. When that got solved, problems emerged with laminating such glasses together, as small bubbles started showing up. 

In the end, we came to an arrangement of what size of bubble in laminate can be visually acceptable, as it was not reasonable to waste all the well-made glasses if the bubbles are 2mm or less.

4  INSTALLATION    

The installation is another topic which is very interesting. 

To fit all the glass panels between 2 laser cut stainless steel profiles at top and bottom following the edge curves of the glass. The corners of the glass were designed to be cut, so that the transom is one laser-cut piece. 

Finally, the contractor changed a little our proposed method of installation, but it was reasonable.The final result is ‘FANTASTIC’ as expressed by Robert-Jan when he went to the opening ceremony. Although I have not been to the project yet after completion!

The final glass façade 

The final façade expressed several other optical distortions, which were anticipated partially. These imperfections enhanced the visual quality of the façade. 

5  EPILOGUE 

While the Louvre Pyramid is astonishing architecturally for its brilliance in terms of its gesture towards the old while being iconic, the UCCA by OMA does one more thing in addition- it drives a new technical research driven experimental glass façade to express the architectural idea. The project was finished within six months from finalization of design!

The project also makes one realize that although industrial production and technological advancements have made us desire more and more perfection in geometrical appearance, slight imperfections arising out of manufacturing limitations are worth accepting and can create interesting effects. 

Also, once these imperfections are not seen as impediments to quality, we are in a better position to create more challenging  facades- factory produced, technically advanced, hand-crafted like facades!       

It was a pleasure working on this project with the great team.

---------This article is transferred from VSA Group