Terracotta Troubles: How a Fifth Avenue Co-op Faced the Challenges of Facade Repair

Many apartment buildings with terracotta details are beautiful to look at, but with beauty comes expense if the material needs repair. Dane Barnes P.E, partner at Joseph K. Blum, was hired to do a façade inspection at a prominent Fifth Avenue co-op and found multiple cracks on the terracotta cornice. Small cracks often signify dangerous conditions underneath. “When we see these kinds of conditions our heart sinks because we know we’re going to have to give bad news to the board.” In this episode of Problem Solved, Habitat editor Paula Chin interviews Dane Barnes to learn how the bad news was delivered, what materials were proposed for the fix, how the project passed all the regulatory hurdles, the project cost and the final outcome.

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Transcript

Paula Chin: Welcome to Problem Solved, a conversation about challenges facing New York co-op and condo board directors. I'm Paula Chin of Habitat Magazine and with me today is Dane Barnes, partner at the engineering consulting firm, Joseph K Blum. Facade repairs are a never ending headache. For boards, especially at older buildings.

Repointing or replacing brick or limestone are challenging enough, but when you are dealing with terracotta, things can really get complicated. Dane, you work with a building or you are working with a building where the terracotta cornices were literally falling apart. Can you tell us about what happened?

Dane Barnes: Sure. And nice to meet you and nice to speak with you today. We're working with a building on the Upper East Side on Fifth Avenue, a prominent pre-war structure, and we were hired to perform the Facade Inspection and Safety Program report and submit it for Cycle Nine with the Department of Buildings.

This is a law that requires any building over six stories tall to have an inspection every five years and evaluate their facade for potential conditions that need to be repaired, or are unsafe. On buildings with terracotta, this is always precarious inspection because terracotta can be a difficult and expensive material to replace.

So in this particular instance, unfortunately we found a number of cracks on the cornice and there was a lot of street frontage of that cornice-- about 150 or 200 linear feet of that. And when we did these inspections, we actually followed it up from a boom truck and had the board join us and we FaceTimed with them so we could show them what we were looking at because they were relatively small cracks if you don't know what you're looking at.

But I guess we soon explained to the board small cracks with terracotta can actually imply much more significant and dangerous conditions underneath. 

Paula Chin: Dane, can you explain to us what a cornice is? What did that comprise in this building and what exactly is terracotta?

Dane Barnes: Sure. So the cornice is the highest point of an elevation, the top of the building, right?

Many people think of them as parapets. It's the part of the masonry that sticks up above the roof. And a cornice in particular is an additional component of that parapet that actually cantilevers out and sticks out over the sidewalk. Lots of them in New York City, especially in these pre-war buildings.

They're a decorative design element. Primarily adding aesthetics to the facade and beauty. Terracotta itself is really just, you can think of it as like clay pottery. When you might look at a design element on a building, like a column or a coping or a water table, oftentimes those are made of limestone or granite or a different natural stone material, and they're solid.

In the case of terracotta, it's actually hollow on the inside and the entire object or stone that you are looking at from the exterior is actually only about one inch thick all the way around. And on the inside you have a bit of a honeycomb structure to keep it structurally strong. But unfortunately what that means is when you start to see cracks, those cracks probably penetrate through the entire thickness of the terracotta.

Paula Chin: And then does that become not only a problem of the terracotta itself crumbling, but is there some structural potential for damage underneath that? 

Dane Barnes: Yes. So the terracotta cannot support its own weight, so it's not up there holding itself up. Underneath it is a steel substructure, usually comprised of angles and threaded rod that are tied back to the building steel skeleton or the structural skeleton.

And over time water gets through that terracotta through the joints typically and the steel substructure becomes exposed to water and storm water, and over time it rusts. And when steel rusts, it increases in volume, it pushes outward. This is known as rust jacking. And when that happens, you can get cracks in the terracotta, and unfortunately that can cause pieces of terracotta to fail suddenly and unexpectedly.

When we see these kinds of small cracks, we know we have to take them very seriously. 

Paula Chin: Unexpected failure meaning things crumbling and falling down onto the street. 

Dane Barnes: Correct. The particular building we're working on is about a 20 story building. And, a piece of terracotta that can fall from the building could easily weigh 10, 20, or 30 pounds.

These are things that could be lethal. 

Paula Chin: So what are you seeing? You mentioned small cracks and it sounds like you FaceTimed with the board. . What do you see and what were you showing the board to help them understand what it meant? 

Dane Barnes: So I was explaining in very much the same way I'm explaining to you.

Again, we were on a Zoom. I had one of my employees on the boom. I'm the partner and the engineer of record for the project. And then we had multiple board members and I would direct him to ask the boom truck operator to move to various points where we had seen some concerning conditions, and I would explain what was going on there underneath the facade. So I would say, listen, there's a small crack here, but you can see that this crack wraps around or under or through this piece of stone, and it shows up on the other side, and this tells us that we know there's a piece of rusting steel underneath that.

And this piece of steel could fall. And in fact, in a number of locations, we were able to remove pieces of terracotta with our hands. 

Paula Chin: So there was obviously in some cases very dramatic damage . Were there chunks coming apart or things crumbling actually in your hands as the people touched them?

Dane Barnes: Yes, correct. And we are, gentle with it. When we're doing this, we're not causing this damage. People often think, stop doing that. You're causing damage to the building. Unfortunately, once we see these cracks there the damage is already done and this clay material is very brittle.

Now terracotta is a strong, good and durable material. This is happening after this terracotta has been on the building for a hundred years. But once it starts to fail, there's really no good options for repair. You can patch it, but I really don't like to patch this material.

'Cause remember, it's hollow inside and so it's really hard to be sure that you are creating a sound patch. It's easier to patch solid stones like limestone or cast concrete because you know that material is solid all the way through its thickness, and the patch has a good bond to the rest of the stone.

It's hard to be assured of that with terracotta. 

Paula Chin: Was this a landmark building? I understand a common problem or further challenge with terracotta is that when you have to replace it, it obviously has to be approved by the Landmarks Commission. 

Dane Barnes: Yes, that's correct. Often these pre-war structures with terracotta design elements are landmarked buildings and in general, landmarks wants to replace those kinds of historical materials with identical matching materials. When you have to replace terracotta with terracotta in kind, it adds a lot of time and often costs to the overall project. There are different ways you can repair or replace a bcornice once you've come to the conclusion that a cornice needs to be replaced because the damage is that extensive. You can replace it with cast concrete stone.

You can replace it with GFRC, which is a material known as glass fiber reinforced concrete that has a steel substructure and has a similarly thin shell. To the layman these materials almost look identical. And then another option is fiberglass. I don't often specify fiberglass because I feel like it fails a little bit sooner than these other materials.

In this case, we were able to work with landmarks to get approval for GFRC, which we were very happy about. It's going to make the project go a little bit faster than it would have otherwise. 

Paula Chin: You mentioned that generally the Landmarks Commission wants terracotta to be replaced with the same material.

So how did you therefore convince them to go with something different? 

Dane Barnes: So we had originally proposed replacing the cornice all the way down to the window head of the top floor apartment below, which also had terracotta design elements over them, these decorative semicircles. And there is masonry in between.

And by eliminating some of that and proposing GFRC, which is a lighter material, we could explain that. We could tie this. GFRC back to the structural skeleton and weld it in place and not impose any structural load onto the material below, thereby preserving it. Terracotta block has to bear in some capacity and some of the stones have to bear directly on the stones below in a load-bearing fashion. And by eliminating that, we were able to preserve some of the other existing older material which Landmarks liked. 

Paula Chin: Now, if you had gone with replacing it in kind how is that done? Or how even is this done? How do you create the pieces to replace it that obviously are the same as the original?

Dane Barnes: Yeah, so this is one of the big struggles with replacing terracotta. There are only two manufacturing facilities in the United States that produce and manufacture and replicate terracotta for architectural facades. One is Gladding McBean in California, and the other is Boston Valley, located closer here in the Northeast.

But they have long lines and long queues to get in line. When you produce those stones, often it takes six to 12 months to get the materials back to the building after you take them off. When you take off a terracotta stone, you have to pin it back together or glue it back together any way you can to keep the original shape and then the original stone and you ship those on a truck out to one of these two manufacturing facilities.

They then make a mold of it and make the new stones and then ship them back. And it's really like making clay pottery. They make the mold, they fire it in a kiln. They put a glaze on the outside and send it back to the site, but that manufacturing facility often shuts down a construction project for 4, 5, 6, 7 months while the demolition and all the other repairs on the building were completed and we're just waiting for stones to arrive.

Paula Chin: So in this building, you ended up replacing, I think you mentioned 150 linear feet, a whole band of cornice. That's a big job. 

Dane Barnes: Yeah. It's a very big job. And when we see these kinds of conditions, again, they can look minor to the untrained eye, but our heart sinks when we see this.

'Cause we know we're gonna have to give bad news to the board. We don't have any interest. In finding big and expensive and difficult projects for buildings. But at the same time, our obligation is always first and foremost to the public safety and to the people walking underneath these facades.

And I always explain to buildings, listen, who are the people that walk underneath your buildings, more than anybody else? The people who live there. So usually get on board when I say that. 

Paula Chin: How much was this project and does using the replacement material, the substitute material, did that bring the cost down?

Dane Barnes: Yes. So this project is going to cost the building of about $1.8 million all in. That's, there's a number of different costs that are involved there, but by being able to use GFRC instead of terracotta, we probably saved somewhere in the order of three to $400,000, 

Paula Chin: Not an insignificant amount.

Dane, any final takeaway for our listeners? 

Dane Barnes: One, I would just make sure that these every five year inspections are on the board's radar. They know that they should know that they typically result in facade repair projects. And if you live in a pre-war structure or one of these beautiful old buildings that we have all, all over New York City that have decorative terracotta elements on them. Be aware of what that might mean for your bottom line and start saving money for future projects. 

Paula Chin: And from your end in regards to convincing boards of how serious a problem is and your Zoom use, seeing is believing. 

Dane Barnes: Yes, absolutely. I really like to encourage our staff to use modern technology.

I say take videos, not pictures, right? Always take pictures. But if you're up there on a scaffold, a moving image helps people understand scale. And when you know lightly tap a condition and a piece of stone falls off, it becomes very obvious what the problem is. It's not them just taking our word for it.

Paula Chin: Dane, this has been really informative. Thank you so much for joining us today. 

Dane Barnes: Thank you so much, Paula.