Christopher Johnson is a Vice President, Building Envelope, and New York Regional Representative at Entuitive. Recently, we sat down with him to discuss the state of façades with a focus on high-performance glass.

Chris, thanks for sitting down with us. What do you see as the direction of façades today?

Hi Alison, my pleasure. That’s an interesting question because at first it sounds like an impossibly broad query, but actually I think there is a simple answer that is being driven both by legislation and overall design trends, and that is: “high-performance”. And I do mean that on several aspects, ranging from structural performance to environmental performance, and of course cost-efficiency.

In your opinion, where does high-performance glass rank as a material choice for enclosures?

For me personally, glass is a favorite material. It’s so versatile and can be used responsibly and effectively in so many different ways. That doesn’t mean, however, that it’s always the right solution, and I do feel that one has to use the correct material in any specific application. But again, because the term “high-performance” can refer to so many different aspects of a building envelope, there are myriad ways to use glass to achieve performance: laminated glass fins or transoms, three-dimensional formed glass panels, vacuum insulated glass panels. The list goes on for ways that one can achieve an energy efficient, innovative, and beautiful façade using primarily glass as the material.

Even if a client doesn’t want to use glass as the primary enclosure material, it’s rare that glass doesn’t make an appearance on a building in some way. And in those cases, the glass still has to perform to some degree.

Glass abounds at the Comcast Innovation and Technology Centre in Philadelphia.

Are there special challenges to using glass in New York?

I would say that the main challenges in New York are related to cost and codes or standards. With respect to cost, glass as a raw material is not particularly expensive, but when you begin to process it into boundary-pushing design solutions then you start to see costs rise. These premiums come from a variety of places: increased handling costs due to oversize elements, lamination or IGU processing, higher quality control tolerances, etc. The cost of using non-conventional glass in the US is further pushed up due to the limited number of fabricators of specialty glass assemblies and lack of competition. This typically forces one to look overseas to source materials, and that adds time and shipping costs.

An example of pushing boundaries – structural insulated glass at the Canadian Canoe Museum.

Codes and standards can also present challenges, particularly relative to structural glass and quality control. As a structural material, glass is still not as widely guided in the codes as other materials like steel or concrete, so many times structural glass solutions need to go through a lengthy and/or challenging process to be accepted by the municipality, for example.

On the quality control side, the US glass industry is still largely guided by ASTM, AAMA, and GANA which might be considered in some cases too conservative (i.e. when it comes to structural design factors) or too liberal (i.e. allowable distortion) depending on the issue at hand. One reason for this is that the domestic glass industry is still heavily weighted by the residential market, which typically deals with smaller lite sizes and more conventional glass applications.

What’s something unique related to your approach to working with glass?

I still love to think of glass in terms of its alchemy. Even though I understand very well the chemical and physical reasons why this happens, there is still something magical about how we take opaque raw ingredients in granular form (sand and lime), add a whole lot of heat, form it in some way, and when it cools is born this glorious transparent solid that is paradoxically quite strong and delicate at the same time.

I don’t know exactly how that poetry finds its way into my resulting work, but it’s definitely something I think about.

How do you factor energy and daylighting performance into your designs? Is sustainability a consideration?

Sustainability is always a consideration for Entuitive, and for me, too, it’s a top a priority. That said, and although it’s getting better, glass as a material is not terribly sustainable at the moment. This is due to two main factors: the difficulty in recycling architectural glass, and the amount of energy and emissions that go into producing float glass. The latter point is likely to be addressed more easily as renewable electricity gets even cheaper and factories upgrade their facilities, but recycling glass after being laminated, coated, adhered, etc., is costly and laborious.

When it comes to energy performance and daylighting, the technology and available products out there offer so much, it only takes the will to implement that into a project. There is no silver bullet, however, and many designers feel there are sometimes aesthetic trade-offs that have to be made when a certain level of performance has to be met. I think this is a matter of perspective though; beauty comes in many different forms. So, maybe the glass on your building has to be 5% more reflective; it could be saving thousands of tons of CO2 per year in building energy usage, which is a beautiful thing too.

A climate circular – an example of our energy modelling capabilities.

This question of aesthetics versus performance is of course subjective, but it comes down to the philosophy of the designer. What is it worth to the project (and my conscience) to forsake the overall performance of the building envelope, and therefore its impact on the Earth, in order for my original artistic vision to be fulfilled? Would I similarly sacrifice the functionality of the building itself? Now, these rhetorical questions assume that design is a zero-sum game, and I don’t actually believe that; I’m a proponent of the “win-win scenario” rather than the “trade-off”. What I mean is, there are always ways to keep the project beautiful and highly performing at the same time. I think of these as design challenges rather than disappointments, but it helps to also be thinking about this from the beginning of the concept design phase rather than waiting to consider how well the building is performing until the end of design development.

Interestingly, this whole discussion is the reason that we started our Advanced Performance Analysis group here at Entuitive. This brilliant group of engineers and data scientists work with the project teams to look at every aspect of a building’s performance, from radiant heat to reflectivity to human comfort, and the information we gain from this is fed directly into the design process in an iterative way. It’s just another way for us keep working towards making buildings as highly performing as possible.

Are there any upcoming trends or changes in the world of building envelope that you can forecast for us?

I think I’d rather answer this as a wish list rather than a prognostication:

I hope to see more recyclability of building façades, and more recycled products going into them. I hope to see a design trend where zero- and even net-negative emission buildings are the pinnacle of status, with the envelopes playing a primary role. I hope to see further developments in certain business models in the industry that begin to incentivize high-performance materials, methods, and designs.

To this end, Entuitive’s increasing work in areas such as mass timber, modular construction, and composite materials is helping to push innovations in building envelopes in tandem…so hopefully, some of those wishes aren’t too far away.

And, finally, a lighter one. What’s a super memorable project you’ve worked on?

The very first built design I ever worked on was for a private house for a bison rancher. It was a long single-story house in a shotgun-plan that floated above the rural site, with one full length of it enclosed by a 16’ high window wall so that from every room the owner could always see his fields, the sky, and the horizon…so simple; I think about this one a lot. Too often we think that strong design concepts need complex solutions, but I think we forget that sometimes a simple answer is both easiest and more beautiful.

Thanks for taking the time to sit down with us, today, Chris. We learned a lot!

If you’d like to reach out to Chris to discuss this article or your building envelope needs, you can do so here.

Earlier this year, Chris gave an interview to I