Terra Cotta Facades: Assessment and Restoration – 2017

Erik Valentino, Masonry Preservation Services, Inc. (MPS)

This year, Erik Valentino continues his participation in the AE 537 (Building Performance Failures and Forensic Techniques) visiting practitioner lecture series with an encore  presentation titled “Terra Cotta Facades – Assessment & Restoration”  This topic is a part of the masonry module for the course and comes after a very interesting campus site visit to Old Main to see the restoration and rebuilding work MPS is doing in conjunction with the WJE led east stair restoration and Old Main assessment project.

Mr. Valentino’s has presented several masonry related topics to the class over the years.  You can view the summary, reference material and discussion of one of his previous historic masonry presentations by going to the Building Failures Forum post: Historic Mass Masonry Restoration. You can also find some good tips on all forms of masonry restoration including brick, stone and terra cotta (the subject of this post and discussion) by visiting the Masonry Restoration page on the MPS website.

As noted in the National Park Service Preservation Brief 7 summary (see below for link to full brief): “Today, many of this country’s buildings are constructed of glazed architectural terra-cotta. However, many of these are in a state of serious deterioration and decay. Glazed architectural terra-cotta was, in many ways, the “wonder” material of the American building industry in the late 19th century and during the first decades of the 20th century. New technology and methods of rehabilitation now hold promise for the restoration and rehabilitation of these invaluable and significant resources. Restoration/rehabilitation work on glazed architectural terra-cotta is demanding and will not tolerate halfway measures. Today’s preservation work should equal the spirit, attention to detail, pride in workmanship and care which characterized the craftsmanship associated with this widely used, historic masonry material.”

Unfortunately there are fewer craftsmen with the skills to repair and restore terra cotta than ever before. In addition, many architects and engineers are not familiar the performance and special techniques needed to investigate and execute terra cotta restoration projects. A good start in educating yourself on the topic (especially if you were not fortunate enough to have attended Mr. Valentino’s seminar) is to read and study Preservation Brief 7 (provided below) and enter into the discussion that follows at the bottom of this post.

For more detailed information and extensive references on architectural terra cotta:Download the Bibliography of Architectural Terra Cotta

Additional reading on the topic of Terra Cotta preservation and restoration can be found by using the link provided below to Preservation Brief 7

Preservation Brief 7

The Preservation of
Historic Glazed Architectural Terra-Cotta

National Park Service

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29 Responses to “Terra Cotta Facades: Assessment and Restoration – 2017”

  1. Josiah M
    November 12, 2018 at 8:29 pm #

    Mr. Valentino’s presentation on terra cotta gave great insight into a material that, until now, we haven’t had any exposure to. One of the major takeaways that I got from this presentation is that a quick fix isn’t necessarily the correct fix. Mr. Valentino mentioned that quick fixes are not only ineffective, but they could possibly even accelerate the damage. One of the examples that was presented was a building with deteriorating terra cotta on the roof, the deterioration was a result of water intrusion. As a quick remedy to this issue, someone made the decision to apply a spray roof membrane in hopes to slow down the deterioration and save money. However, the membrane acted to lock the moisture in which will only degrade the terra cotta further. This will probably end up costing the owner even more than it would have to properly address the damage.

    It’s interesting to see how these quick fixes can end up in a more involved and costly solution to the issue. If owners were a little more hesitant to take the easy way out of these sorts of problems, the may end up saving extra expenses.

  2. Clayton T
    November 12, 2018 at 8:27 pm #

    Mr. Valentino’s specialty in terra cota facades combined aspects of failure investigations, structural engineering design and architectural design. Although there is a surge in the implementation of terra cota into new buildings, historic restoration is a major piece of the industry deterioration within the material itself as well as the supporting structure. What I found to be most interesting was the quantity of specialty engineering that new needed to be incorporated into the original design of the supporting structure and the way it ties in the building it is attached to. Along with this the investigation of preliminary design and repair being able to analyze the existing system or what little may be left of the exist system and understand how the load was transferred to redesign components that act similarly to the original. In a perfect world, the original design would be well documented and readily available in the future but this is rarely the case, as Mr. Valentino explained, design often is pieced together from common attachment methods used in that time period and possibly destructive investigation if need be. However, the retrofit design won’t always work perfectly with the existing conditions and often need to be changed in the field emphasizing the level of communication between designer and construction parties.

  3. Abby S
    November 12, 2018 at 5:43 pm #

    I enjoyed Mr. Valentino’s lecture, especially his discussion about the terra cotta restoration process. I think it is very interesting how people are able to recreate historic terra cotta elements to match damaged or failed elements. The effort and detail involved in the process is very impressive. Mr. Valentino spoke about the coordination involved with ensuring all pieces fit properly so that the repair is not noticeable, and he mentioned that sometimes pieces need to be reshaped if they are too large to fit within the design. I would be curious to see what measures can be taken if a piece is smaller than intended and does not fit. I also found it very interesting to learn about the process of matching the terra cotta finishes and how slight differences, such as surface reflectance, can greatly affect the outcome. If the wrong finish is used, this can be a costly mistake. Another concern with the restoration process is using materials that are incompatible with the existing materials. These examples show that even the smallest details and choices in terra cotta restorations can impact the result. I think this is especially important because of the historic weight that many terra cotta buildings hold, including the ones on Penn State’s campus.

    • Katie W.
      November 14, 2018 at 7:40 am #

      Hey Abby, I think you brought up some valid concerns with the restoration process in your post. The job of exactly matching what was constructed a hundred years ago is no easy task. Of a piece is smaller than expected, I imagine that unless the difference is very slight and can be filled with mortar/sealant, the piece would have to be remade. Matching colors exactly is probably a tricky process and it is important to remember to clean the existing terra cotta so you can have the actual color of what you are trying to match to. Though after looking at some of the examples presented in class in not just the terra cotta presentation, there are many instances where the new repair is obvious because of how clean it is in comparison to the rest of the building. I wonder whether they take this into account and ever purposely try to match the dirty materials so it will fit in better.

  4. Jackson H
    November 12, 2018 at 10:59 am #

    Terra Cotta is a unique material that has many issues that are similar to masonry and concrete. Water penetration, corrosion, spalling, and cracking are all issues shared between these materials. Although terra cotta fell out of fashion in the 30s-40s, there are an abundance of buildings that use terra cotta elements, and many of them are in need of rehabilitation. Rehabilitation is important for aesthetics but one thing that I noticed from Mr. Valentino’s presentation is that a lot of this decorative masonry repair should be completed for safety reasons. Chunks of terra cotta falling off the sides of buildings can cause major injuries to pedestrians below, and seeing how easy it can be to just remove chunks of deteriorating terra cotta by hand can make one nervous to hang around the walls of these buildings. Netting can help prevent pieces from reaching the ground, but as shown in the presentation, netting isn’t always used properly. In the case of the Radisson Hotel in Scranton, the wing of the terra cotta eagle above their main entrance is ready to fall off, and instead of performing the proper repairs, the owner has opted to cover the wing in netting. According to Mr. Valentino, the netting they used to hold the wing back would not be sufficient to stop the entire piece from falling off, which is dangerous and a liability for the owner. Most of this terra cotta work is extremely detailed and requires in-depth knowledge of construction methods from almost 100 years ago. Restoration of these elements is an important task because it is a part of our architectural history and because deteriorating facades can pose a safety hazard to occupants.

  5. Steven B
    November 10, 2018 at 3:00 am #

    The building envelope encompasses all the elements of the outer shell of a building that maintain a dry and insulated indoor environment. Although Terra-Cotta is primarily an Architectural material, it is still part of the envelope and is often called open to aid the other elements. What is surprising is how much the issues and mechanizes of concern when designing your building envelop manifest themselves within terra-cotta members. You must use materials that compatible with terra-cotta. Using the wrong mortar or the wrong support material could possibly create undue stresses in a material that is not good in tension. Of course, water is the great nemeses to yet another construction material. Small flaws in the finishing of the terra-cotta piece such as cracks, finishes or even small gaps may lead to major failures from water intrusion.
    Unlike most other building failures, terra cotta failures may be more of a safety concern for the public outside rather than the occupants of a building. Perhaps this has to do with the fact that if an architect is going to spend the time and money to design and make a feature out of such a labor-intensive material, that feature is likely going to be a prominent part of the overall look if the building. That feature must stand out which usually mean that it is hanging out over high traffic areas so that they can be seen. This means that when there is a failure, there is a high risk of such a piece falling and hitting someone below.

    • Clayton T
      November 13, 2018 at 8:48 am #

      You made a good point with the time spent into architectural design and terra cota as a labor intensive material with it being usually a prominent architectural feature. What surprises me is the lack of maintenance and very often the implementation of quick fix to save the building owner money. Understandably not all repairs can be done immediately and some take precedent over others but as you explained the terra cota is not only an major architectural feature but can result in life safety issues if not managed and repaired property. It seems to be that if the repair is postponed, the greater the failure becomes ultimately resulting in more loss to to the building owner. However, I feel that many building owners are not aware of the the kind of prolonged damage and terra cota and wonder of ways to educate them of the dangers and pitfalls of avoiding repair.

  6. mkev
    November 8, 2018 at 6:11 pm #

    Now for the challenge. Who can be the first to identify which buildings on the UP campus have Terra Cotta. This includes facade elements and roofing (basically historic clay tile). Most of these by definition are historic buildings. Terra Cotta (in simple form) is making a comeback in the USA and there is at least one newer building where Terra Cotta has been used on the facade so include that one if you can. Prize for the first person to get the entire list. Post answers under this comment for all to see.

    • Smithr
      November 13, 2018 at 3:41 pm #

      Two buildings that I walk past every day that appear to be terra cotta are the Armsby and Weaver buildings. They have some of those trim pieces that are “fake brown stone” and have a lighter color behind the chips in the masonry. Patterson is also of similar style but I couldn’t find any of the identifiers that was presented in class.

      • mkev
        November 13, 2018 at 4:11 pm #

        Good start Smithr. Armsby and Weaver (in the area referred to as Ag. Hill) have clay tile roofs so we count them in the broad category of Terra Cotta. There are at least three more old ones and a newer one, one of the old ones which is a text book case of the way Mr. Valentino described how to tell if something is Terra Cotta.

    • Katie W.
      November 14, 2018 at 2:59 pm #

      I was looking at facade details around older buildings on campus, and i think the cornice detail along the roof of Sparks and Burrowes buildings might be terra cotta. It is colored like stone but it has a lot of small details and was built around that time that it was in use.

      • mkev
        November 15, 2018 at 4:09 pm #

        Katie,
        You are correct. I have seen documentation that the area you are discussing on Sparks has some Terra Cotta and some cut stone. Hard to tell from the ground.

        So the list so far is:
        Armsby
        Weaver
        Sparks
        Burrowes (likely and and I have seen some during the renovation)

        Still two more traditional ones to go and one relatively new building. Updates or new guesses welcome!

  7. Smithr
    November 8, 2018 at 2:45 pm #

    I am glad that Mr. Valentino came in to present to our class about Terra Cotta Facades because it is a relatively unique facade that I have little to no knowledge about. For starters, Terra Cotta is a “cooked earth”, similar to a hardened clay. Terra Cotta is more durable than brick and inexpensive compared to stone, I am a little surprised that it is no longer very popular.

    From a construction standpoint, it is great that Terra Cotta is able to be molded, because this can greatly reduce the amount of repetitive work for tradespeople. We can see these similarities with cast stone which create a faster construction than historic methods of architectural masonry.

    One point that we have discussed earlier in this class was reiterated by Mr. Valentino. Short-term fixes end up adding on to long-term issues and can even promote an exponentially faster deterioration. I think the best way for us in the construction industry to avoid these short-term fixes is by educating owners about the realities of “kicking the can down the road”. If we are able to present information about the concerns with short-term fixes to owners in an effective way, I think it would give all of us an upper hand towards our reputations in the industry.

    • Josiah M
      November 13, 2018 at 8:37 am #

      You make a good point about the importance of proper repairs and how they can be better for the longevity of the building, when compared to the quick fixes that are normally employed. I think that another way to get owners more inclined to make proper repairs is to inform them of the long term costs that could result in a quick fix, it may seem that a fast solution is cheaper on the surface. However, that type of repair may cause more damage than it fixed and could possibly not even fix the original issue properly. All of this will lead to anoter, more expensive solution later on. If owners knew this, I think they might more inclined to make an informed decision on how to properly adress the damage.

  8. Ryan L
    November 8, 2018 at 12:42 pm #

    When I was younger, I didn’t understand or value the effort put in to preserve historic architectural building systems or materials. I thought that cost considerations and function were the only real “value added” components of building repairs and renovation.

    As I’ve worked on multiple historic renovation projects for DoD facilities, my attitude has definitely shifted and I appreciate the story that buildings can tell, and also how they interact with users, community and context that they exist in.

    Mr. Valentino’s presentation on Terra Cotta is a great sign that even though the expertise to maintain and repair these building components is hard to find, it is still being addressed and even improved upon by addressing common component failures in these systems. There are two buildings in Buffalo that have great terra cotta features that I pass by most of the time when I travel there: The Guaranty Building and Elicott Square Building. Both of which have had extensive repairs done to maintain the original architecture. Hopefully dutiful owners and preservation societies continue to drive the importance of maintaining and improving building components like Terra Cotta

  9. SamZ
    November 8, 2018 at 11:31 am #

    The presentation about terracotta given by Mr. Valentino was very informative, before this presentation I had limited knowledge of terracotta enclosures and architectural features. Terracotta offers an incredible amount of flexibility in color, shape, and ornamentation for building facades and exteriors at a considerable discount compared to an equivalent in stone. Although having many similar applications as stone it has different maintenance and deterioration issues. Many of these issues stem from corrosion of the steel supports and hangers, that can have varying degree of section loss from 0 to 100%. A notable thing about the steel corrosion is that there is little or no indication of whether the next unit over from a failing unit is totally fine or has significant loss of section requiring most if not all units in question to be taken apart to verify their condition. Another aspect from the presentation that I appreciated was Mr. Valentino stressing the importance of conducting a proper and worth while repair. He showed many examples of bad patches that were purely cosmetic to cover up a crack or spalling that didn’t address the reason it failed in the first place. This type of repair is destined to fail again and or compound the issues, all it does it waste time and money. It is always better to fix the root of the problem correctly and as soon as possible.

    • Sierra S
      November 9, 2018 at 8:32 pm #

      I believe the idea of applying only a cosmetic “patch” to a building could never produce a positive result. This applies to what Mr. Valentino was saying about the architectural finishes. The details failed due to a reason and until that reason is addressed the problem will not be solved. To a more extreme end this could also apply to the structure. Today in our seismic class, we observed the failure of a eccentrically loaded brace frame. This system “failed” properly based on its design. A small section of the beam deformed and caused some paint to chip instead of a failure of a major structural member. After the earthquake, however, that section of beam is intended to be replaced. This painted finish can’t just be touched up in order for the system to perform for the next earthquake.

      It is important that building owners understand the need to provide regular maintenance and repairs to their building. While the patch “fixes” may work short term they just lead to expanded problems and higher cost down the line. Not only is there higher costs but their is also safety problems. Architectural details can fall off the side of the building or members can fail. I wonder if there is a way to regulate building maintenance and care.

  10. Eric I
    November 8, 2018 at 10:16 am #

    Mr. Valentino gave a very insightful presentation on the unique material of terra cotta. Terra cotta came to light in the late-nineteenth, early twentieth century due to its relatively lightweight, low cost characteristics compared to natural stone. Terra cotta was also popular because it was able to be produced in a wide array of colors, mimic stone materials, and be adapted into very ornate architectural features. News of wide-spread deterioration started to make its way around the industry and its popularity declined dramatically. As for today, a great deal of historic buildings utilize this material and the art of restoring and understanding the causes of deterioration has become a valuable practice.

    As Mr. Valentino explained, a large portion of these failures are caused by water infiltration, induced stresses and insufficient repairs. It is very common to find that original designs lacked proper water management systems such as flashings or weeps. This creates a domino affect where cracks can form from the freeze/thaw cycle or the steel supports corrode from long term moisture exposure. Stresses induced by building movement or thermal loads can cause the cracking as well. In order to effectively repair terra cotta, the forensics engineer must be able to identify what is the root cause.

    One thing that Mr. Valentino brought up multiple times, which seems to hold true with all of the topics we have discussed in class, was the necessity of wholistic, long-term preservation efforts over “quick fixes.” Terra cotta is a complicated material to work with and it requires a deep understanding of the small details. Many of the preservation efforts involve historic, one of a kind structures that are otherwise irreplaceable. Maintaining these buildings and their unique components is essentially working to preserve history.

    • Sam Z
      November 12, 2018 at 8:43 pm #

      Eric, I appreciate your comment about failures caused by water infiltration. This has been a reoccurring theme for the entirety of this course, but it is something that I don’t think can be over stressed given how common this issue is. Terracotta is good example of a material that can have a long service life, but attention must be given to the details and how to manage water. This was something that terracotta facade designers were doing later in the material’s adaption with flashing to shed water away and weeps to remove water that gets inside. The incorporation of weeps I think was very beneficial because it just is not a reasonable assumption that an enclosure over its life time will be always water tight. A better design is to anticipate leakage to some degree and have a plan to mitigate this built in. It is too bad these lessons were not learned soon enough to prevent terracotta from falling out of favor given it can be versatile and durable material.

  11. Katie W.
    November 8, 2018 at 8:32 am #

    Though I did not have the chance to attend the lecture, I read up on the references and the powerpoint presented in class. I find it astounding that originally people believed terra-cotta was waterproof and needed no flashing or weepholes. Water infiltration and subsequent deterioration of the supports and reinforcement is a common theme in building failures. It is especially important to maintain the mortar and sealant joints so water cannot get in. In terra-cotta it can sometimes be difficult to detect the full extent of the damage hidden behind the facade. Often the damage is too severe when it is found and can pose a danger to the public. If a piece falls off, it can be a sign on underlying problems. It is important to investigate the connections and flashing and treat the source of the problem and not just the exterior issue.

  12. Jordan O
    November 8, 2018 at 2:26 am #

    Mr. Valentino’s Guest Lecture on Terra-Cotta facades was one that I was very interested to hear about since part of my most recent summer internship involved the inspection of terra cotta and detailing the repair of defective areas. It is a very prominent material found on facades in NYC, but as Mr. Valentino suggested, it began to fall out of favor in the mid 1920-30’s due to deterioration issues. It is a very useful material when properly detailed and installed, and allows for extremely intricate levels of ornamentation for buildings that would otherwise be bland. Wide varieties of colors are also able to be used in terra cotta, allowing for much more freedom in expression for designers when using this as their chosen cladding material.

    The main issue noted in this lecture is the frequent issues with detailing when used in combination with steel anchors. Often times either the detail is not drawn or executed properly, leading to steel exposure to water which in turn causes expansion when it corrodes, and ultimately the failure of the connected terra cotta. Proper flashing must be detailed and installed along with weeps to allow for drainage. The installation of these pieces must be carefully executed and checked throughout the process, and having a commissioning agent on site would greatly reduce the possibility of future failure.

    The assurance of this process going smoothly has the potential to save the owner a significant amount of money, as well as ensuring the facade maintains its original look. A big positive of terra cotta is the ornamentation that comes along with it. When a detail is designed, the same mold is used over and over to guarantee the same detail throughout the facade. In the event of a failure, an owner will most likely want the facade to be restored to original conditions, and this will be very difficult without having the original mold, proving even more how important it is to get it right the first time.

    • Smithr
      November 8, 2018 at 2:48 pm #

      I agree with Jordan that verification during construction is a big part of ensuring quality of work. This is especially true in systems that are somewhat unique, where workers may not have experience working with this material and therefore can make errors without even knowing that they are wrong. I would encourage this process to take place with the help of a building enclosure consultant as opposed to a commissioning agent to ensure that inspection could occur before the building was completely constructed.

      • Jordan O
        November 13, 2018 at 2:00 am #

        Smithr,

        I’m not sure how significant the difference is between a consultant and a commissioning agent, but my interpretation of this was that the most important thing is to have someone there to guarantee proper construction. Another less viable option could potentially be to require a base level education of the workers higher than the current level so they are guaranteed to be competent enough to prevent simple mistakes that could lead to failures. The effectiveness of either of these probably comes down to how much it would cost to put workers through that base level education compared to the total amount paid to a commissioning agent/ consultant throughout the life of the project. If the education does prove to be effective in the long run, it could be an incentive to owners while also keeping buildings in better shape more often.

    • Eric I
      November 9, 2018 at 8:03 pm #

      Jordan,

      I think that you brought up a good point in addressing the versatility of terra cotta. The variety of color choice, appearance, and design freedom provided makes it a truly unique material. While all of these are great things, it must be designed properly to last. This requires careful detailing and installation efforts that may go beyond the knowledge of your average engineer or contractor. With so many historic buildings containing terra cotta in disrepair, highly specialized efforts are often required.

      I agree that restoring terra cotta is an excellent opportunity to utilize commissioning agents on site. With so many small, intricate parts involved with terra cotta construction, having someone around to verify quality is a worthwhile investment. Restoration is a complicated process but maintaining the original look of these structures is a benefit to us all.

    • Abby S
      November 12, 2018 at 5:57 pm #

      Jordon,

      Your internship experience with inspecting terra cotta sounds very interesting. I think you make a lot of good points about the freedom and flexibility of using terra cotta in a design. Mr. Valentino discussed how they create the molds used for these designs, and it seems like a very detailed process. I think the use of terra cotta sounds like it can create a lot of challenges and require significant upkeep, but the aesthetic rewards seem to make it worth the effort.

      I also agree that bad details can lead to a lot of failures with this material. Mr. Valentino showed a detail and the way their assessment found it was actually built, and they were very similar, which I found very impressive. I think this demonstrates the importance of designing and constructing these details. I agree that having someone on site for inspections would greatly reduce the amount of terra cotta failures.

  13. Sierra S
    November 7, 2018 at 3:20 pm #

    In many ways I found the failure of architectural terra cotta similar to concrete failure. Both materials are not strong in tension, therefore when water penetrates the material and reaches the steel it is only time before the section falls apart. The reaction the water has with steel causes the steel to corrode and expand, exerting stressed onto the surround material. This creates a need for special attention for detailing of these finishes. This need was recognized an caused the creation of the National Terra Cotta Society which produced industry standard details. These details were applied in construction, as indicated in Mr. Valentino’s cornice repair example. The industry is constantly adapting to meet the new demands.

    As a side note, it constantly amazes me how the building industry is constantly trying to make structures look like something they are not. From faking different finished to hiding the true structure. For example, the U.S. Capitol Building has a steel structure but it is covered to give the impression that it is a made up of concrete, similar to the Pantheon. This “mask” is the same for trying to find cheap material to simulate high end products, as done with terra cotta.

    • Jackson H
      November 12, 2018 at 10:15 pm #

      I was also interested by the wide uses of terra cotta that I had never seen before. I had always thought of terra cotta as the red-orange material that some roofing shingles were made out of. I didn’t realize that it was used so extensively as an alternative to stone carvings. I always thought that intricate façade work like the examples that were shown in class were either actual stone carvings or cast concrete. For a material that seems to be fairly durable, lightweight, and versatile in terms of finish, it is unfortunate to see how it dropped out of popularity after a rocky start, even though means and methods were developed to remedy many of the initial issues.

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