Stone World

Architects Roundtable: Studios Architecture

October 1, 2002


Since its formation in 1985, Studios Architecture has grown both in size as well as in its scope of completed and ongoing projects. And over the years, the firm - which currently has offices in San Francisco, Washington, New York, Los Angeles, Paris and London - has also seen its use of stone increase over the years.

Moving from its early interior work for high-tech firms, Studios is currently working on a broad range of civic and urban building projects. At the time of Stone World's visit to the firm, two of the major projects in progress were Foundry Square, a speculative office complex in San Francisco which is using a broad range of stone materials; and the City Hall building in Milpitas, CA, which is being clad in limestone.

Last month, Studios Architecture received the 2002 Firm Award from the American Institute of Architects, California Council (AIACC), the highest award a firm can receive from the council. According to the AIACC, the award recognizes distinguished architecture consistently produced over a period of at least 10 years, along with mentoring, continuing collaboration among individuals and significant contributions to the advancement of the profession in the areas of design, research, planning, technology, practice and innovation.

Stone World's roundtable included the following members of the firm's San Francisco office:

  • Charles Dilworth, AIA, Principal
  • Julia Campbell RIBA, Associate Principal
  • David M. Johnson, AIA, Associate
  • Clifford A. Wong, Associate


Stone World: Describe the type of work done by your firm.
Dilworth: We were founded in 1985 in Washington and here in San Francisco, and we have other offices that are an outgrowth of that. Our practice really began with corporate interiors. Most of the people who founded the firm had been affiliated with a previous firm called EPR - Environmental Planning and Research - which was a large, nationally based firm that did predominantly interiors. Within about five years of our founding, we had expanded into doing quite a bit of architectural work, but it was all in the private sector, because that's what we wanted to do.

In the last three to five years, we have been expanded into institutional and civic and academic arenas. We are doing both interiors and buildings, and we have also been doing some campuses in some cases. The commercial work has also continued, and an obvious example is Foundry Square. So we have diversified.

I think if you look at the first 10 years of our work, you might have a hard time finding any stone. The first was Norwest Tower in Minneapolis, MN, and there were a few other high-profile projects that had a lot of stone. But the typical project was for the high-tech industry, and there wasn't much stone because of the association [of cost] with the material. They might be putting in materials that cost just as much or more, but the association is very different.

Stone World: Was there a perception that stone was an "old" material that would be more appropriate for banks and law firms, but not for new high-tech firms?
Dilworth: Yes. I think there was stone on some of those projects, but it was used in unconventional ways. Of course, there was the occasional slate floor or something like that, but much of [our more extensive stone use] came later.

One example would be the City Hall that we're doing in Milpitas, CA. In that case, the same association of stone that made it not work for high-tech industry made it work [for a municipal project]. We had a City Council that function as the client, and they basically had a preconception in their mind to use stone from the word go. They liked that it would convey an impression of permanence, solidity and so forth.

Stone World: But the stone was used in more of a modern application.
Dilworth: Yes, and that was why they chose us. It was a combination of Studios [design style] and stone. We used a limestone, and I believe its source was Egypt.

Stone World: How did you find that stone?
Dilworth: Through the stone contractor. They had actually showed us two limestones from Egypt, and we had originally selected a stone which we had understood to be Egyptian, which would be finished in Italy. It turned out that the stone was being quarried in Lebanon and finished in Egypt. And when the City Council found out about that, they decided to go with the other stone. So when you're talking about a negative issue about stone, there is the issue of distribution - particularly from Third World nations. You have a client who is in love with a stone that has been marketed to them, but for all intents and purposes, it is unavailable.

Stone World: We've seen a lot of that, particularly for companies that are just starting to export to the U.S. Since the U.S. has become more a user of natural stone, we're seeing more overseas producers and exporters just beginning to market their stone here. In some cases, the distribution network is well established, but in others, more work needs to be done.
Campbell: We had a lot of issues with an onyx that we selected from India for the United Airlines red carpet lounge at Heathrow Airport. I had to go to Carrara, Italy, three or four times. Each time, it wasn't ready or it had to be cut some more. And we had to select the onyx and match it, and there seemed to be a lot of issues with the entire process.

Stone World: This brings me to another question. When you bring in stones from areas like the Middle East, are they usually fabricated in a more traditional place, such as Italy?
Campbell: It seemed to me that everything went through Italy, wherever it was from, and it would be cut there.
Johnson: Recently, we're seeing China as not only a source, but as an area for stone cutting. And so we're seeing a lot of stone supplied for projects that is being cut and fabricated in China.

Stone World: Over the past 10 years or so, China has brought in a lot of the Italian machinery, and so the quality has improved. What is the level of craftsmanship that you're seeing?
Johnson: It's been very good.
Dilworth: I did my bathroom at home in a very inexpensive Chinese green marble, and it was cheaper than ceramic tile. It's a dark, highly figured stone, but the background color is all the same. One of the tricks, though, is that it has some curing problems, so you need to use an epoxy-based mortar.

Stone World: Having done much of your early work in the private sector, can you describe the move into doing institutional work?
Dilworth: I think in terms of client relations, it was very different. Certainly, the process of getting the work is extremely different. But the actual work really is not. We considered what we were doing in the private sector to be innovative, and [we felt] it actually had a lot of application in public sector projects - particularly certain types of public sector projects. I think that has actually proven true. The work in the end doesn't seem that different. Getting there was a bit different, though.
Campbell: I would say the approach to the interiors - for instance Corey Hall at UC Berkeley - is definitely about [achieving] much more of a timeless feel, rather than a "now" approach. We know that in Corey Hall, maintenance is at an absolute minimum, if at all, and they are not going to do anything to it for 20 or 30 years. So, therefore, the materials you select need to be durable and are not necessarily fashionable. We specified a quartzite.

Stone World: You mentioned that the firm's use of stone has increased over the past few years. Has that been because of a change in the project types that you're working on, or are all project types using more stone?
Dilworth: I think it's a change in project type, personally. It's very hard to say with what the economy is doing right now. I think if you were doing a typical commercial project right now, the likelihood of it being more budget-conscious is extremely high. I think that would not reflect well on the use of stone, either actually or perceptually. I think the perceptual aspect might be the greatest [obstacle.] I can imagine right now that if you were doing an interior for a bank or a law firm, even though the stone might be cheaper, you could very likely be told, "Let's not use stone right now because it sends the wrong message in these tough times." That hasn't happened yet, but I could see it happening.
Johnson: In the recent past, material selection has been driven by what is appropriate on site for exterior cladding or interior work. In Julia's case, stone was chosen because it is durable. On Milpitas City Hall, it is a civic or urban gesture. This was the same concept for Foundry Square; it's the idea of a formal facade in an urban context. It's really project specific and value based; what is appropriate and what is right for the project.
Wong: Stone has a perception of value and impact. It is going to provide durability. And that perception is very important. A lot of our clients selectively use stone, whether it is on the stone or on the wall. We don't need miles of stone, but it's still a statement.
Campbell: We use it in the important areas, where you want to make a statement.
Wong: We often have clients who just want stone from the beginning. They know that it is a durable product, even for a desktop. If you have a wood top, and you place a binder on it, maybe it will scratch. So they would rather pay for the stone up front than to pay for refinishing the wood top.

Stone World: In your progression from manmade materials to stone, what are some of the practical lessons that you learned?
Campbell: Don't use granite where you have orange juice. We used a black granite for the bar at United Airlines and it stained terribly. There was a milky film that just looked awful. We ended up having to put stainless steel over it. We should have used glass, but they wanted a stainless steel that they could just take off and clean.

Stone World: Was the stone sealed?
Campbell: Yes, but it just ate right through it.
Johnson: On the exterior side, I think the firm has been exposed to a lot of different cladding technologies. At Milpitas, the stone is on a strongback or a stud wall. And Cliff has done some different applications.
Wong: We have done a variety of applications -- a masonry wall behind a veneer with a cavity; anchoring systems onto metal studs; truss systems.

Stone World: How do you go about choosing the different systems? Are they suggested by the contractor?
Wong: Mostly, it comes from the application and the knowledge of the height requirements. Also, it depends on what the substructure is. If you are working on an interior project, then it's just light-gauge metal stud framing. We're going to look at the economics. We won't put a structural steel frame wall back there. We'll use the metal studs and sheath it with plywood and then attach [the stone].
Johnson: At Foundry Square, we have about 55,000 to 60,000 square feet of stone on precast. The stone was put in a mold with rebar and a concrete cast on top of that. That was a design/build system that was brought to the table by the contractor, Clark Pacific. They have worked with us on a design/build basis to engineer and document the systems, and now they are building two of the four buildings.

The first stone was Burlington Stone out of England, a slate. The second building is primarily red granite from India. The third building will be a yellow limestone from Pakistan, and the fourth building will be a Jerusalem limestone called Ramon Gold. All of the stone is 2 cm, and at the base of all buildings we have honed Absolute Black granite. Except for the Burlington Slate, Clark Pacific has been sourcing the stone for the exterior from Carli out of Italy.

All of our plazas are 3-cm Impala Black from China. We had all been dubious of it, and it had been selected at a huge savings. There was a new technology used there, which was stone on foam. It's an open-joint plaza system, which is stone on wire-cut foam that has been glued together. That's a common installation out here now. The concrete slab is sloped to drain and waterproofed, and they set foam blocks that are oversized on top of that. And then with a proprietary system, they wire-cut them and place the stone with spacers.

It's a very large collection of four plazas, and then we carried that stone into the lobbies as an interior stone. Inside, the stone is traditionally set on a mortar bed.

Stone World: What are some other practical lessons with stone that you've experienced over the years?
Wong: You try to learn and to figure those things out before the application. It's just like looking at the substructure. There are a lot of different substructures, and you use economics in designing the substructure. Then you come into how you anchor or secure or assemble the stone onto the walls.

Just as there is a variety of stones, there is a variety of techniques to anchor and secure it. A lot of the time, it's based on the type of stone that you're using. And sometimes you just don't have that information available. The appearance of the stone is one thing, but how to use it is another.
Johnson: Because we don't understand all of the cutting and milling technologies, we make decisions early on about how it's going to be done. I know there are new technologies out there that allow more complex shapes or cuts to be done efficiently and economically. The only downfall, though, is that by choosing a more complex method, there may only be one or two people in the world that can do it. But there is a lot of new technology out there that we can explore more.

Stone World: Since the stone industry is growing so quickly in the U.S., there is a concern that there may be some new suppliers in the field who don't have much experience or knowledge of stone. What separates one supplier from another?
Johnson: Service is making a difference. People that can communicate well and quickly, and can serve you in the fast industry that we work in are the ones that win. Although much of it is cost, it's more than that. One of the lessons learned recently was the use of the Internet and photographs to quality control stone. Digital photography is very easy to use, and sending photographs over the Internet is easy. You solve problems where the stone is being cut, rather than solving problems once the stone is on the job.

Stone World: Is the color reproduction of the stones accurate, or can it vary depending on the computer's monitor and how it is tuned?
Johnson: One thing that we learned is in photography, the camera reads different that your eye. Also, wet stones show differently. But through experience, we learned the kinds of differences between a photograph of a stone and a real stone. But it's something you have to learn through hard experience. There's no table that says, "Back down the red and increase the white," or so forth.
Wong: One of the things about the stone industry is that there seems to be no stone standard. There are other industries - particularly wood - that have definite guidelines. The American Woodworking Institute can tell you what types of finishes to use - a gloss; a sheen; whatever.

When you're talking about stone, you have the ASTM standards for testing. But because the stone industry is so broad, there are many places where stone is brokered from. So when you ask for the test results, they may not have any. That makes it very difficult to work with different manufacturers because they cannot produce the information you need, and we don't know if the stone will meet our standards.

Stone World: Do people look at the Marble Institute of America as a source of technical information? I know that they have a design manual that offers some standards for specification - not just for marble, but for all stones.
Wong: They look at [the Marble Institute] for guidelines, but then they have to expand on the aspects of how applicable those guidelines are for the stone. It's a good guideline, but you can't just use those specifications for a marble and then make them applicable for a granite or a sandstone.
Johnson: You also have to look at who paid for what. I know that even the ASTM gets lobbied heavily by certain groups and not by others. So when a standard is generated, it shouldn't be a huge surprise when it happens to have a bias towards something. If somebody happens to have a truly independent source, I would like to know about it.

Also, how you measure rupture or flexure on certain stones can really change the results. We wanted to use a Brazilian slate for Foundry Square, and it offered a huge cost savings. But there were issues with the stone that could not be measured with standard ASTM tests. Because of the way that the stone was formed in the earth and then quarried, it had an issue with eruption on the plane of the bed, and there is no test for that. There is no test for the kind of failure that we were afraid of. We really wanted to use the stone, and there was a great cost savings, but that's an issue for emerging markets. They have to find ways of measuring things like this. There could be completely different issues of a Chinese marble or something that no other stone has ever had.
Wong: It depends on how knowledgeable the distributor of the stone is. Are they just a broker, or do they really know the stone and whether it will meet the specifications?

Stone World: What level of knowledge are you typically seeing from stone suppliers who come in here with samples?
Wong: The people who come in here are knowledgeable, but sometimes the sources where they get their stones from are not nearly as knowledgeable. We'll find out right away when we open the specification and give them standards. They go back and ask their suppliers, and they may not be able to get a positive answer.
Johnson: My experience is that the industry is very good in the U.S. There are very few bad experiences where people are trying to sell you or use inappropriate material.
Wong: It would be a big risk on their part to do that.

Stone World: How do you go about finding new materials? Do the suppliers come in and tell you about them, or do you go to them and say, for example, "We have a project where we will need a tan stone."
Wong: It varies. You know what products you are looking for, and you can call up your sources and ask for a match. But until you bid the job, somebody else can literally take it away at the last second. There is another matching stone out there in the world, and as long as it meets our specifications and our appearance factors, our clients are looking at the bottom line.

You are still specific to the appearance and all of the features of the stone, though. Take Absolute Black granite, for example. Everyone is calling it Absolute Black here, but maybe there's something with another name that's the same thing.

Stone World: In the end, who is responsible for switching the stone? The general contractors? A common complaint that I have heard from the stone industry is that a company will work hard to get something specified for a project, and then they get switched out for a few cents per square foot.
Wong: That usually comes from the subcontractors, not the general contractors. The general contractors are pretty knowledgeable about stone, but they won't have the specifics. They will go to their subcontractors and say, "Here is the stone and the specification." And [the subcontractors] know who the competitors are, and they may find something that is cheaper.
Johnson: I think that the MIA color plates are good for that reason, because everybody has them. So it's a fast way that you can communicate the direction that you are going in. The Internet is also a good resource. There are some sites with stone libraries, and that is becoming a better resource. You can find out about Spanish slates or Spanish limestones very easily, for example, and you don't have to go through a middleman to do it. And by searching wide early and using your networks early, you are not faced with a subcontractor who may have a better idea.

But if you are on a cost-sensitive project that doesn't have a particular allegiance to a stone for some other reason, it's really hard to defend the people who have worked with you up to that point. There are no guarantees.

Stone World: Coming more from the stone industry's point of view, the stone suppliers feel that it's unfair that they work to get a material specified, and then they are switched out at the end.
Johnson: But general contractors and subcontractors are smart enough to know that those alliances and networks and allegiances get you where you want to go on the next project. You may save somebody a couple bucks on this job, but then you've lost that contact for the next project.
Campbell: Also, if something goes wrong, you need solid relationships to make it right in the field.
Johnson: There's a value to those things, especially on larger jobs. Some people get it and some people don't.

Stone World: What do you find is the most challenging aspect of working with the stone industry?
Wong: Stone has almost always been used as a veneer. How often do you see a cubic stone? And every designer is trying to make a veneer stone look like a cubic stone. It has to look like a solid piece of stone, and that's the most challenging aspect of it. If a stone is on a wall, and it's turning corners, then you're putting a lot into the detailing to try and make it look solid.
Johnson: We often have to push stone to its limit - either in size or thickness - and then mount it on a wall and trust what we have been told about the test data. One of the challenges is being cost responsive, which squeezes everything down, and then having to believe all of the test data. You have to be comfortable with the liability issues.

A lot of the technologies were developed for traditional buildings, and when you want to do a modern building, you may use stone in a new way. And you may start asking stone to do something that it may not be able to do easily. That's when you get into trouble or into interesting situations.

Stone World: You've done work for a broad range of clients. Do different types of clients want different amounts of influence on your design? What is the difference between working for a developer as opposed to a City Council?
Johnson: Charles can speak towards a City Council, but I would say the client type is probably a lot like a build-to-suit client. There are some items or materials or issues that are going to be non-negotiable in a build-to-suit project. In a spec market, there are fewer things that are not negotiable. Everything is negotiable.

Stone World: What would be an example of something that is non-negotiable?
Johnson: On Milpitas, it was limestone, because to them, it meant civic and timeless. It achieved the stature that they wanted to portray.

Foundry Square is more than a million square feet of spec office space, and there we have stone facades. That was done because it was believed by the owner and by the city to be the appropriate urban response. To characterize spec projects and developer projects as insensitive and not friendly to stone would be wrong. They hire us to sort out what is appropriate.

The market on the West Coast is really changing, and design/bid/built projects are becoming more and more rare. A lot of civic, city and institutional projects are being done by developers for that entity, so the whole project delivery is changing out here. Developers aren't just doing simple office space. They are delivering projects to other public and institutional entities.

Stone World: When using stone for a project, how closely do you work with the stone contractors - the fabricators or the installers? You had mentioned going to Carrara for one project.
Campbell: That was for United Airlines, so getting back and forth was obviously easy. Since it was their red carpet lounge at Heathrow, it was a very public place, and they wanted to make sure the quality was consistent with our design. I think that is why they saw the value of us going and checking the onyx. We had also used a White Carrara marble for the paneling, but that was more consistent. We knew we would get a certain quality there.
Johnson: If the slabs can be sourced locally, then it's a no-brainer. You can just go there. But if the slabs or blocks need to be sourced elsewhere, I think that's where we have interaction with the quarries or the fabricators. But I have found that in Italy and also in England, using local independent quality control personnel saves everyone money. There are some old hands that you can hire in Italy that are quite capable of monitoring the process more frequently for you.

Stone World: Has anyone ever needed to visit the stone quarries?
Wong: For a sizeable project, someone will be on site to see the stone and how the process is going along.
Campbell: A lot of it has to do with timing as well. You want to make sure that everything is on schedule, and that you're going to get the product when you need it.
Wong: It's interesting, though, how much the subcontractors have to do with where they obtain the material. Even from a fabrication standpoint, they'll go to different sources because they are more familiar with their techniques of anchoring.

Stone World: What else drives stone selection?

Wong: We worked on a project 10 years ago near Flagstaff, AZ, and the stone was right there. And since it's in their backyard, it's an economical material. We built a planter wall in Arizona sandstone and we even used it for tables. People in Arizona are able to really use a lot of that stone, even residentially.

Stone World: Is it always economical to use a local stone, though? I just wrote about a project in Arizona where they used an Indian sandstone to replicate the local material. Also, I recall that at Denver Library, which was designed by Michael Graves in the mid-'90s, they ended up using a limestone from Germany to replicate the tones of Colorado sandstone because it gave them a great cost savings.
Johnson: There are so many factors in the cost of stone, though. To narrowly talk about color and cost isn't enough. Some sandstones have an iron vein that goes through them that makes them very hard to make into slabs. Or they become very fragile. Or maybe there is a sandstone from India that can easily be quarried in thinner sizes to suit the design.

I don't think that you can ever know all that you need to know about stone. There is so much that drives

the cost. It's not just that the stone is local or big or small. Every stone has a story, and every stone has unique characteristics. And until you learn about that, you don't really understand the stone.