Is building with glass sustainable?

I have recently joined London Sustainability Exchange (LSx), as a Project Volunteer and have been tasked to write a monthly ‘Sustainability in Architecture’ article to be included in the LSx news bulletin.

For my first article I chose the subject of glass and briefly assessed the rapid development of glass skyscrapers in the City of London. 

See my article below and view the LSx Bulletin via this link: http://charityemail.org.uk/CXK-2OWJM-B78OU91O20/cr.aspx

Sustainability and Architecture- Glass BuildingsPicture6

 

 

 

 

 

 

The recent development of iconic, entirely glazed skyscrapers changing the London sky line, including The Shard, The Cheese Grater and The Walkie Talkie, prompt the LSx to question how sustainable is building with glass?

Glass is a high energy, high cost material and as the construction sector develops towards transitioning to a more efficient design and building process we question is there still space for glazed buildings? The recent discussions led by architect Ken Shuttleworth and Arup engineers about whether the glass sky scraper is a thing of the past prompt the LSx to review the rapid development of glass skyscrapers in London, and wonder what the future holds for London’s landmarks.

In the 1920s Mies Van Der Rohes Glass sky scraper concept defied laws of materials and was a vision of a technological future. The Ideology of glass depicted then was of simplicity and ultimate modernism. Ninety years on we continue to heavily use glass, especially in iconic London landmarks. Despite glass being expensive and high in manufacturing energy it is still seen as modern and is vastly used in building today. In the current environmental context, the construction sector should be developing and using new innovative materials as an alternative to glass, that have a positive impact on our environment and society; materials that lay the foundation for a sustainable future.

Picture1Manufacturing glass is a high energy process and it requires extremely high temperatures. The energy used to produce glass for the entire facade of the Shard for example was on a tremendous scale. The shards white glazing means that the transparency of the building is a prominent feature however; the internal appearance appears messy and disorganised, drastically affecting its crystal shard like appearance. Furthermore, due to the particular white glazing used, the solar gains are vastly increased and require complex internal environment control.  However, The Shards glazing system is passive and is coated with a colourless solar-control coating, Ipasol made by Interpane and an integrated solar blind system claims to reduce solar gain by 95%.

Fundamentally, glass lets a lot of heat in and out. The preventive method to reduce solar gains and heat loss in glazed buildings is a tremendous feat of engineering and design. The Leadenhall building nicknamed The Cheesegrater, similar to The Shard, has a technical three tiered glazing system with integrated solar blinds. Despite being a very clever and innovative solution to overheating, from an Picture2environmental and economical viewpoint, it may have been better to design efficiency into the building rather than having to expend time, money and energy to mitigate the negative impacts on internal environment caused by glazed curtain walling. Architects are fixated on glazed facades; planners desire glazing and the public enjoy the iconic stylised designs. In order to achieve efficiency in building and develop toward a sustainable built environment glazing needs to be reduced.  

Despite the obvious environmental problems with building with glass, many more glass skyscrapers are planned to be completed in the City of London over the next five years. The reality is that iconic landmarks and quirky shapes dominate architectural design, prioritising aesthetics over efficiency and sustainability and it seems the vision for the future of the City of London is wholly ‘glass skyscrapers.’

 

 

Future glass sky scrapers in the City of London: 

20 Fenchurch Street- The Walkie TalkiePicture3

Completion:2014, overdue

 

 

 

 

 

52-54 Lime StrePicture4et- The Scalpel

Completion: 2017

 

 

 

 

 

 

 

 

 

Picture5

The Bishopsgate Tower- The Pinnacle

Completion: construction on hold since 2012

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3 thoughts on “Is building with glass sustainable?

  1. Absolutely. Glass buildings are enticing to architects, being able to construct diagrams for buildings that were once impossible. Developers like glass because curtain wall is a modular product that can be made off-site, shipped and erected quickly and efficiently–which is why even in the developing world we are seeing new glass spires on city skylines. Realtors like glass buildings because views are something that the market has told them they can sell. But the truth is that glass buildings are not all that sustainable, or at least not when compared to a building that has more solidity on its exterior wall.

    Another aspect of glass buildings that always seems to get slipped under the rug is the realities of curtain-wall glazing. Most curtain-wall suppliers warranty their products for around 30-35 years, namely the glazing seals that secure a watertight joint between the glass and the metal frame around it. so what exactly happens in 40 years when glazing seals start to fail? Remove the entire skin of a glass building? Cover the building with scaffolding to reglaze in place? It’s one of those big question marks that has serious implications to the lifecycle cost of a building.

    The Urban Green Council actually did a great study that points to the fact that both residential and commercial occupants turn out to use “views” out of all glass buildings much less than one would think–implying that what is paid for as an amenity actually becomes more of a nuisance. Worth checking out:

    http://urbangreencouncil.org/seduced-by-the-view

    • Thanks for the great comment T.Cane, its nice to have some feedback and you raise some excellent points.

      I have always believed in design for a reason. Every detail must have a direct use or a fundamental need to be there. Glazed curtain walling seems to defy this rule and The Urban Green Council’s research proves this. The research states that 56% of glazing is covered by blinds, in my eyes that is unnecessary waste and the design has therefore failed to not only provide its users with a suitable internal environment, but also failed in efficiency of material, which leads to unnecessary mediation of over heating/cooling. Simply the design should have had 56% less glazing.

      Having said that, I look back at my architectural designs whilst studying part one and despite my efficient design outlook I still used a lot of glass. It seems to just be the modern way of designing (im not saying the right way). Im sure if i was tasked to design a building with a small percentage of glazing i would find it difficult (maybe not, the idea actually excites me). In fact i would probably burry the north elevation under earth and have a glazed curtain wall to the south…….

      Ultimately there is drastic need for a change is design outlook and process in order to begin creating efficient buildings and spaces, and the reduction of glass in designs seems to be an obvious stepping stone.

      • Agreed. I would say a lot of the tall buildings that come out of our office would start with the assumption of a glass tower, despite the fact that we are considered to be a sustainable firm. Modern or not, the default inclination to glass buildings is probably something that should be revisited–especially in the parts of the developing world where temperature and heat gain are even more of an issue for energy use.

        A better example of a conscious glass building is the Heron Tower in London by KPF. They use some nice moves to add to the efficiency of the building. Another example would be something like 300 Layfayette St by COOKFOX. Indeed it is a glass building, but glass that is shaded by deep recesses that support exterior green space.

        http://intercongreen.com/2014/04/21/green-buildings-300-lafeyette-street/

        Another great one still is the addition to the Cambridge library by William Rawn & Associates. Their solution was a double-skin wall with integrated, programmable louvers.

        At the same time, I don’t think modern has to be synonymous with glass. A look at Masdar City in Adu Dhabi points to what an architect like Norman Foster can do with very little glazing in a very demanding environment. The result is still decidedly modern.

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