Laser Scans and Leaning Towers: How Technology Is Revealing Facade Faults

What happens when a multi-million-dollar condo conversion hides serious structural problems in plain sight? Restoration architect Hannah Sebastian, co-founder of Mayta + Sebastian Architecture, walks board directors through a real-world case involving a landmarked former church near Washington Square, where leaks, failing marble, and a visibly — but not obviously — leaning spire sparked years of debate with shareholders. Board members will learn how advanced tools like laser scanning and BIM modeling helped cut through skepticism, clearly communicate risk, and ultimately build consensus for critical (and costly) repairs. The conversation offers practical lessons and concrete strategies on how data-driven visuals can defuse shareholder resistance, and why accurate records and phased capital planning are essential — especially in landmark buildings. Habitat’s Emily Myers conducts the interview.

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Transcript

Emily Myers (00:39)
Welcome to Problem Solved, a conversation about challenges facing New York co-op and condo board directors. I'm Emily Myers with Habitat Magazine, and I'm joined by Hannah Sebastian.

co-founder of Mayta and Sebastian Architecture. Thanks so much for being here.

Hannah Sebastian De Mayta (00:54)
Thank you for having me.

Emily Myers (00:55)
So we're gonna talk about facade and exterior restoration and we'll discuss why it's so important not to put off repairs and how boards can deal with these issues proactively. So let's kick off our conversation with a look at a unique co-op that Mayta and Sebastian are working with. Originally a converted church and then turned into high-end apartments in 2006. Can you explain what the problem was, Hannah?

Hannah Sebastian De Mayta (01:21)
Absolutely. So this was a very unique challenge for us. We had never seen or been involved in a renovation or an adaptive reuse to this scale yet interesting conclusion. There was a sponsor that purchased this old church and turned it into six apartments, six very large apartments. And they originally reached out to us because there was water infiltration coming in from the stained glass windows.

which was one of the few areas where the sponsor had not put an entire interior skin, I guess we will call it, to the building itself. So water was coming into those stained glass windows causing mold and moisture infiltration. And our office came to address the two sides of the building. But throughout the process, we did a plan review of the prior developer's drawings and everything. And we came to realize that

there was some inconsistencies with the exterior restoration project and the interior renovation project, essentially that not much was done to the exterior envelope. So little by little as we were inspecting and investigating, we became aware of actually so much larger issues that the building wasn't really thinking of. And it turned into a long standing relationship where now we're the building architect, which is great, but where we started to have these conversations about

what's the long-term effects of what you're doing? What can we do to immediately address this problem? And then what are the underlying effects similar to as if you went to a doctor that give you medicine to make you not have a headache, but we need to figure out why are you getting the headaches in the first place?

Emily Myers (02:56)
So what were then some of those larger issues that you uncovered?

Hannah Sebastian De Mayta (02:59)
The most prominent ones that we found was really general maintenance and repair of the Tuckahoe marble stone masonry. The stones themselves were of course showing signs of wear, but because they were so massive, they were still structurally sound. However, like the mortar and the underlying structural systems, particularly in some of the fenestrations, some of the spires, and some of the detailing near the top of the church was

far deteriorated and over time they had done things like put metal straps to hold things together that was working but was clearly causing sources of infiltration to the building that were going to continue being exacerbated.

Emily Myers (03:39)
So how did the shareholders react then when you realised that the extent of the problem was perhaps much larger than they had thought?

Hannah Sebastian De Mayta (03:47)
Obviously, initially, it was kind of when you get a bad health diagnosis, they were they were pretty concerned. they were very frustrated because coincidentally, the timeline of this was such that it was shortly thereafter the expiry of the sponsor and the builders warranty. so clearly, they were why are we dealing with this?

junk and everybody was frustrated about that. But the thing that really helped us out was because we've dealt with problems like this over the years, we were able to provide them with a two, a five and a 10 year plan for the project. So we were able to say, these are your immediate emergencies. This is obviously what the shareholders are seeing that's affecting their day to day life. Like I've got drips coming from my ceiling. I've got mold on my wall and then provide them with, okay, this will address the immediate issue. But then the next five years, you're going to have to do this.

We actually didn't have anything on the 10 year plan. It ended up being like a 7.5 year plan, but we went through all of that. And then further to that, because of the way our team works, because we had already laser scanned the entire building, because we had modeled it in Revit, which is our BIM methodology of choice, we were able to actually provide them with a bunch of diagrams and a report that really explained with photos and with graphics what the issues were.

They still pushed back a little bit, but little by little we were able to slowly work our way around the building to deal with the progressively more emergent issues. And eventually we actually were able to do a full restoration of the entire front facade, which was the most beautiful one, but the one that had kind of been able to linger a little bit with repairs. And then eventually we did do the spires. But I think that that communication with the board members

is what eventually put them at ease because they knew they didn't want to spend the money. But once it was explained with a thorough and thoughtful way, they were able to understand the value of addressing things now and then not leaving things later.

Emily Myers (05:41)
Okay,

were phasing the repairs over multiple years and presumably starting with a stained glass window, sorting the leaks out and then moving through to, you mentioned spires

Hannah Sebastian De Mayta (05:47)
Mm-hmm. Correct.

Mm-hmm.

Emily Myers (05:58)
perhaps compromised.

Hannah Sebastian De Mayta (05:58)
Yeah, so

the first phase was essentially the two sides of the building, which was the stained glass windows. Interestingly enough, as is a typical New York fashion, buildings had built up on either side, so you could not even actually see the stained glass from outside of the building anyways, but because it was presenting the most issues inside, that was the first order of business. The second order of business was the front facade, which was not presenting as many issues inside because of the nature of the design. So there was a lobby.

there was a stair tower, there was an elevator that was kind of buffering the tenants from seeing that front facade and not realizing that there were still moisture issues. But what really called our attention was even from the street, we were able to see that the spires themselves, two of the spires on the west side were significantly leaning. But because of the perspective that you get when you're looking at the street, was.

arguable that it was leaning or not. But again, we went back and had the conversation with them, showing them our laser scan and the rectified BIM model and explaining to them, this is the angle of inclination, this is what you have to do. So that was the phase two that we completed about a year and a half ago. And then now we're actually at the back, which is an exciting one because it's actually upgrading the building a little bit. This portion of the building had been done

With EFAS, the EFAS was failing. When it was done, it was more experimental of an application that was done. So actually at this point, we're able to remove the EFAS and provide a new system that's more waterproof, that has better insulation for new energy codes. And that part is actually getting upgraded now and we're wrapping up at this time.

Emily Myers (07:34)
And EFAS is a form of cladding that has a gap between the original facade and the perhaps new facade that gives added insulation and protection.

Hannah Sebastian De Mayta (07:43)
Correct.

Yeah, and interestingly enough, the reason that the back facade was able to wait for so long is because actually it is new construction. There's a portion in the building that's internal of the current building now that is the original back wall of the church, and then there's a new back wall of the church. So what is the reason that the rear, I think, was able to sustain or wait for repairs so much is because that was the one part that was

fully constructed interior and exterior as new. So it presented the least signs of moisture and air infiltration because the other three walls, the front and the two sides, were still original masonry and didn't have the same level of insulation or waterproofing inboard.

Emily Myers (08:26)
Wow, it sounds like a really interesting structure. So what's been the cost of the repair project?

Hannah Sebastian De Mayta (08:31)
We are, I think, all in, We're looking at about two and a half million. The front facade was because of the nature of it being a landmark building, because we restored some of the original architectural details that had been dropped off over time and everything. That one was the most expensive. That was about a million. And then the other three elevations are comprising of the rest of the repairs.

Emily Myers (08:53)
And can you provide any more detail about how you repaired or replaced the spires?

Hannah Sebastian De Mayta (08:58)
That was a very exciting one. So it was one of the joys of doing a restoration and a renovation because you go in there with a preconceived notion of how you think it was probably constructed or how I would construct it today with modern technology. Like I mentioned, they had at some point in the renovation or in the alteration, they had put metal strap ties around in a few locations of the spires in an effort to essentially hold it together.

which was generally working, but it was still kind of shifting as a whole. So once we were immobilized, once we had protection and everything, we took the straps off and the stones were heavy enough that just by sheer gravity, they were kind of staying in position. But once we opened those up, we saw zero signs of structural steel reinforcement.

There must have been because there were evidence in the stones of little holes where probably hooks used to be. But over the years, because of the moisture infiltration, they had just completely dissolved, for lack of a better term. And then the brick masonry that was infilling the inside of the column was also basically just dust at that point. So we just took them all down piece by

And then we cleaned out the entire inboard brick.

masonry infill and any remnants of possible structural reinforcement took all of that out and what we ended up doing was putting a new four by four steel column that was tied back down to the lowest portion of sound masonry. We built a new steel column in it, we put metal plates to receive those stones and then the stones were replaced and then we filled the whole thing with concrete.

So that reconstructed the spire. But the thing that we were very excited about as far as aesthetics of the building was that in the original photos that we found from landmarks, there used to be these beautiful copper finials on top of the spires. And that was an interesting conversation because the building did not want to put them because they were an unnecessary decorative cost. However, once we explained to them that in fact, the way that that finial was constructed, it basically was a little cap or a hat.

and the top of the spire was four stones, so there were joints, there was a cross joint. By having that cap on it, it was waterproofing that joint so that water wasn't getting down. But over some course of time, I believe, when we looked back at photos, it seemed like sometime around the 60s or 70s, those came off, that was allowing all this moisture to get in and causing the delamination and the deterioration of the steel and the brick masonry.

So by explaining that to the client, again, with these diagrams and these pictures and everything, we were able to convince them, okay, there is in fact, although beautiful, there is in fact a value to it. So we were able to put them back on, the conversation, if you will, and actually return the building to a more beautiful state than it was when we got there.

Emily Myers (11:50)
⁓ amazing sort of historical detective work these buildings present. So what lessons then do you think boards can learn from this experience? I mean, this is obviously a very unique building, but there are definitely lessons here in terms of being proactive and perhaps going the extra step.

Hannah Sebastian De Mayta (11:57)
It's always a fascination.

Absolutely. think for us as generally as building architects, there's a few things that I see that happen that always breaks my heart on behalf of the buildings. When is your warranty up? So for example, good record keeping like your roof warranty is always going to end six months to 12 months before you find a leak.

So making sure that your management company or your building architect has clear records of not only the drawings and the construction, but also the timeline of prior repairs and prior warranties is very helpful because we always recommend if you know a warranty is expiring, get it checked by a professional. Get a physical conditions report so that then you can go back to whomever is the warrantor and ask them, hey, come check this out. We found this issue.

please take a look at it so they can fix it before the expiry of the warranty. I think that one is something that happens a lot, especially with the transition from a sponsor-owned building to individual unit owners. If you're an individual unit owner or a board manager, you should always ask that sponsor for all the records that you can possibly get. And if you're just an individual unit buyer, I think it's important to always ask the building management and the board for these same documents because you want to know

Are you getting into a building that might have a capital improvement plan coming up in the next two to five years that are potentially going to raise your shareholder dues? Maybe there's an assessment that's going to be given that you don't want to be surprised with. In theory, all of these things are disclosed as part of the sale, but it's not necessarily common sense to look for all of those things. And then the other part of it, I think, is just if those records are not available.

it might be worth an investment to ask a design professional to come out and survey your building to give you a physical conditions report to pull the records from the DOB and compile that all for you. Because I think planning is the key in New York City building management. You know that you're going to have to fix things. There's a freeze-thaw cycle. Nothing lasts forever. But to be able to proactively coordinate those things so that, for example, if you're mobilizing scaffolding,

you can get the most done with the cost of that scaffolding versus doing scaffolding now and then two years from now doing scaffolding again. In many cases on a project of this size or even smaller projects, your scaffolding and sidewalk sheds could be more than the cost of the actual repairs. So if you can group together some repairs and capitalize on that investment, it can really go a long way. It might mean an assessment now, but it means now you did repairs that last 10 years.

Emily Myers (14:46)
Gosh, amazing tips for our listeners. Thank you so much, Hannah.

Hannah Sebastian De Mayta (14:51)
Absolutely, it's a pleasure.

Emily Myers (14:52)
Hannah Sebastian, co-founder of Mayta and Sebastian Architecture. Thanks so much.

Hannah Sebastian De Mayta (14:57)
Thank you.