Making the Case for Slate

The following transcript was made in part by an automated service, in some areas it may contain errors. 

Avi: [00:00:00] Welcome to Deep Green. I'm your host, Avi Rajagopal, the editor, gen Chief of the Architecture Interior Design Magazine. Metropolis. Here at Deep Green, we often shine a spotlight on traditional building materials that have fallen outta favor for a variety of reasons, but that we think should be reconsidered by architects and designers who are working today, especially those who are concerned about the environmental and social impacts of their projects.

In this vein, a few weeks ago, we had a really in-depth conversation about clay tile, and you can find that in your deep green feeds. But today we're gonna talk about a gray, flaky signifier of 19th century luxury that we think deserves a second look slate. Now, before the 1930s when asphalt composite shingles became the most [00:01:00] common roofing materials in North America, our middle class was actually rushing to build Victorian style homes or to renovate their Georgian or colonial style mansions with slate roofs.

And there was a reason slate was easy to maintain. It was elegant in color, and it had excellent thermal properties. And as many beautiful buildings all around the world, proof lasts for hundreds of years. No wonder that there was a slate boom in the 19th century here, and in many other parts of the world where slate roofs have been constructed for a couple of thousand years at least. But what makes Slate a great choice today? And what new possibilities have opened up for this really ancient material? Here with me to talk about that is Drew Ford, the USA regional sales manager for Coupa Clad, who's one of the major slate providers all over the world. Drew, thank you so much for joining me [00:02:00] today.

Drew: Thanks for having me, Avi. It's great to have this conversation with you.

Avi: from your point of view, why do you think architects should be looking at Slate again today?

Drew: Yeah, so Slate is a great option that a lot of architects have seen on those historic projects. Castles, cathedrals. A lot of different projects have utilized it over time. And I think there's a lot of perception about Slate being a high quality, long lasting material, but we're here to really kind of dive into some of the sustainability factors and that economy for the material.

It's not gonna be the most expensive, but it's gonna offer a lot of value for that designer.

Avi: certainly it has this, you know, artisanal quality to it. how does Cooper clad bring that into the modern era?

Drew: Coupa CLA is a part of Coupa Group and Coupa Piz, the world's largest slate producer. One of every two pieces of slate installed in the world is one of ours. So we do have that [00:03:00] capacity for a lot of different sizes of projects. But the Coupa group has been producing Slate under that name since 1890.

So a lot of those projects that we might have seen on those castles and cathedrals is actually that Coupa slate that we're still still producing today. So we're looking at that history and Coupa Clads taking that history, and we really looked at the benefits of the slate, the longevity, the low water porosity, and the high density of the material.

Really allowing it to perform very nicely in a variety of different climates. And the Coupa clad takes to that tried and true slate material and applies some of that rain screen technology to kind of get the best of both worlds with a very long lasting and high quality material on the outside of the building with some of that performance characteristics that that rain screen's able to offer with thermal performance, moisture management of that entire assembly.

So. It's not only taking that beautiful, sweet material, but it's using [00:04:00]building science to get the longest and highest performance system that we can outta the material.

Avi: I noticed that I've been talking about roofs, but you just talked about a rain screen system as well. So there's two things we're talking about here. One is, you know, how do we optimize this material for the building performance standards we have today? But two, also, how do we expand its use from roofing, which has been the traditional use to a rainscreen facade system.

so. Take me through what makes Slate actually a pretty high performance material. Um, and let's also talk a little bit about the, the carbon footprint of this material.

Drew: The material starts three to 400 million years ago. And the crust of the earth as those raw materials. What happens over that period of time is an intense heat and pressure really changing the chemical nature of those raw materials to get a very low water porosity. High density material that we see is that Coupa slate or that Coupa clad.

Now slate is a broad term [00:05:00] for a classification of rock, so it is very important to understand. Where that quarry's located, what do those raw materials went through over that three to 400 million years and the characteristics of that material today? So we really take a lot of pride in the testing and certification that we have on our material.

for the longevity and durability in a variety of different climate zones. So we know that that material is going to last no matter where it's installed. The slate has a great sustainability track record. We do have a carbon neutral certification from Carbon Trust on our production, and that's something that we really embrace is that carbon kind of journey with the material, understanding what that production is taking to produce the material and what the longevity of that material is.

So not only is Slate initially a great sustainable product, but with the longevity of the material and the 100 year warranty that Coupa Cloud offers. We can really look well into the future about the [00:06:00] longevity of that material lasting on that project. And one of my favorite things about Slate is the reusable nature of it.

So if a project after 70, 80, a hundred years decides that they wanted to change that material. We can actually take that slate down and reuse it on another project. So it really extends the life of the material and that cohesive conversation about sustainability initially for the product. But when we look at the long-term impact of that being on the building.

The low maintenance characteristics of the material ensure that we're not spending a lot of money and effort to maintain it, but we're not also impacting that environment on the maintenance of the material.

Avi: True. There's a lot we're gonna unpack in what you just said, but I just wanna take a quick moment to talk about How the stone is actually treated and prepared, for use in buildings after it comes outta the quarry. Can you talk about some of the processes that you use?

Drew: Yeah, definitely. We take out of [00:07:00] our 20 quarries in Northwest Spain. A diamond studded steel chain to cut large blocks of S slate out of the mountain. We then take those large blocks, make them to a more manageable shape and size, Then every piece of S slate we do produce is hand split with a hammer and chisel One of the great things about that production process is no two pieces will be exactly the same. A lot of other products will use a mold or an image technology, so you might have a repeating texture or image. That suite's gonna be unique piece to piece, but the consistency of our quarries is gonna make sure that that color is very consistent and that texture is quite consistent.

Slight variation as a natural product. That gives us that natural beauty, but it is really a handcrafted product that is unique and kind of an ode to that historic slate production that's been done the same way for hundreds of years. Okay.

Avi: [00:08:00] I'm really intrigued by reusing slate. And one of the ways that that's possible is your facade system, right?

The actual system by which, uh, slate is attached or affixed to the building. Tell me about how you develop that system and how it allows for, for this material to be easily replaced if you know. If there is an event of any kind, but also for it to be taken away and reused at the end of life of the building.

Drew: with the company being based in Europe, we did develop the system for the European market initially where a lot of rain stream products have really captured that design community. A lot of benefits with using rain screen materials and systems. So we really were looking at some of those other systems and the performance that they were garnering out of them and wanted to take that slate and kind of combine the benefits that we see with using natural slate with the benefits that we had seen with that rain screen assembly.

So we kind of [00:09:00] developed that initially to give us the best of both worlds And then when we brought that to the US we really saw a lot of excitement for that system. While in the US market, we do see a lot of wood frame construction, so we did develop a system that we refer to as direct apply.

Which includes that mechanical attachment of the slate to an OSB plywood sheathing. that direct apply allows designers and architects to bring slate.

To their projects at an affordable price point with as much performance as possible. that direct apply is going to include slate with pre-drilled holes, Really makes it an efficient install for the product.

And then we're putting a neoprene shim on the backside of that pre-drilled hole. That fastener is gonna penetrate through that shim. Helping prevent vapor moisture from traveling down that fastener. It's also gonna provide a thermal break from the slate to the wall, as well as a small rainscreen cavity behind that material.

And we have partnered with Vapor Shield for the water resistant [00:10:00]barrier and the neoprene shim to really give as high performance of a system as possible for that direct apply assembly. so we can really customize our assembly to the needs of the project.

Avi: you've taken the kind of expertise that say a Slater in the 19th century would have, and then. Added this layer of engineering and ingenuity to it, um, to create a really flexible system that today's installers can work with. it allows commercial and residential projects today.

to access those amazing qualities that Slate has. You know, its thermal properties, its maintenance, um, ease and, and all of that. such a fantastic journey that you've taken with this, with this material. I wonder if you can, um, give us an example of maybe a project in the US where, the system has actually been put in place and how it's performing.

Drew: Yeah. I have two different projects that kind of come to mind when we think of the benefits. One is [00:11:00] a direct apply project They had initially looked at using a painter's brick on the project. We introduced the Coupa clad material to them. Kind of explained the benefits of that slate and the simplicity of that direct apply system. And I think that's something that really kind of perked their ears up a little bit was the ease of that install your average siding contractor can install Coupa clade without issues.

and we were able to install for less than that painter's brick for a couple of dollars a square foot less.

Not only saving money initially on that project, we were also able to save money on the long-term maintenance of the material. a beautiful facade day one year 50 year 100 and beyond. So Not only saved money, but was a more environmentally friendly option for the long-term maintenance of the project. Now when I look at, uh, a Rain Stream project that we had in the Chicago area called the Conservatory Project, this was a very interesting one.

[00:12:00] They used actually our 2 0 1 Vanguard system, which is an exposed clip. That exposed clip is a little bit different than the system that we've been talking about. Where you screw in the piece of slate with a clutch drill The system supported with a clip. Exposed with a stainless steel gives a little bit of an architectural detail and an o to that traditional slate install Now this project was an affordable housing project in Chicago and they did want to achieve passive house with their performance characteristics on it. So it not only met the needs of the project on a me measurement But it did give that longevity with low maintenance that really saved the efficiency for them on the project. And then with the ability of that full rain screen system to accommodate continuous exterior insulation, we were able to aid in that performance characteristic to achieve that passive house certification and was the largest affordable housing, passive house project in the Chicago area. So [00:13:00] really proud of that project and the suite being incorporated in there.

Avi: going with a. traditional material can often be such a simpler route than, dead ends. We work ourselves into trying to get, you know, color and, and performance out of, uh, you know, cheaper but composite materials and as you said in the end.

Slate turned out to be more economical, but also have this great maintenance life. And we don't think of traditional materials like slate as high performance materials. And you're talking about a passive house project that has very high standards for thermal insulation and Slate actually has amazing thermal property.

So it's working with that installation under the rainscreen facade. And I love that, you know, you, you shared that project with us we've kind of lost our ability to work with a material like slate.

We don't, often, have experience and the [00:14:00] understanding that that's needed, and we need to look to providers like you to provide that expertise. So how do you support teams? How do you help them discover the best way to use Slate on their project?

Drew: I think one of the most important things that I can offer to the architectural community. Our A I A Lunch and learn presentations, they do give a a great opportunity for me to get in front of their office, their whole team, and really dive into natural slate in general as a cladding material, but get into some of the specifics with that assembly for the full rainscreen system, the direct apply, and some of those characteristics that make it a great material for their project.

So a lot of times it's that initial conversation. because a lot of architects, when I talked to them initially, they're like, Hey, I love Slate. I just don't think I can afford it. And it's an exciting conversation because we get to educate them on the cost of slate siting and the benefits that it has I really like to get engaged with that architect. Make sure that we're really [00:15:00] specifying the best system for their project, for performance and budget. And then as we get to that bid stage with the gc, since a lot of people haven't worked with sleep before or they've, it's been a long time since they've worked with it, I really like to engage them to make sure that they're comfortable with the material, how that system comes together, and what the vision the architect had in mind for that assembly.

So they're very comfortable as we get those installers bidding that project. So I like to get initially with that designer to make sure that they're comfortable with the characteristics of Slate. One of the things I really like about the Slate is even though it is a dark charcoal gray or black and direct sunlight, it will have a very nice silver metallic shine and shimmer to it.

It's really gonna pop depending on the weather. And that's some of the character of that natural material. It's not gonna look the same every time we approach the project. The lighting, the weather is really gonna impact that look and feel. So getting them excited about what Slate can offer them. At the same time educating them on the performance that we have [00:16:00] with the material.

But that cost effective nature because at the end of the day, if the project can't afford the material. Then it's not gonna go up. So we not only want to show them how beautiful, natural, sweet can be for their project, but how it can be a very cost effective option as well for that project.

Avi: I. Started this episode talking about, how a slate has often been a signifier of, of, you know, luxury and class. but it's not lost on me that the example you gave in Chicago is an affordable housing project, which typically have very, very stringent budgets as well. So, you know, that's the other thing you've done is make this material accessible.

Drew, is there anything else that you'd like to tell architects and designers about, using Slate on their projects? Um, any new possibilities coming up or, you know, any other piece of information to share?

Drew: Yeah, I think one of the great things about Natural Slate, we do have some of those standard systems, some standard patterns for them to take a look at. [00:17:00] But we do have a lot of flexibility with the material to create custom patterns, custom shapes, with the slate. So it gives them a lot of design flexibility to be creative, to think outside of the box with the orientation of the material, the shape of that slate.

And on some projects, we'll see a pattern as the majority of the facade, and then they'll want to emphasize a certain area of a project. With a custom pattern or a custom install of the material. So I think that's something that's always exciting is, you know, we're willing to explore what options we have to meet their vision and really work in as a team with them to find out the best options, get as close to what they want as possible.

And that's what it really excites me about working with the design community is seeing their creativity with. Something as old as late. We can look back hundreds, sometimes thousands of years with that material's usage, and we still have new [00:18:00] patterns, new ways to utilize that material and modern design.

Avi: Absolutely. drew, thank you so much for being such a great advocate for, for Slate and Materials. Like it. while. We shifted our industry, you know, especially in the, post World War II period to working with plastics and composite materials. Given what we know about the environmental impacts of some of those materials as well as their performance capabilities, I think it's time we look at.

simple, noble, honest, authentic, as you said right at the start, materials like slate, which inherently have great performance properties and with a little bit of engineering, support can be deployed on modern projects. Um, so thank you so much Drew for educating us today. I really appreciate it.

Thank you for joining us.

Drew: Yeah. Thank you for having me, Avi. I appreciate it.

Avi: deep Clean is produced by the Surround Podcast Network. This episode was created in [00:19:00] partnership with Cooper Clad.

You can find out more about their incredible slate offerings in the link in our show notes. This episode of Deep Green was produced and edited by Rob Schulte, with support from Rachel Santo, Lauren Volcker and Barry Te Lister. We're talking to experts in sustainable architecture and design all this year, and a new episode of Deep Green Drops every few weeks, so catch the next episode of Deep Green wherever you get your podcasts.