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

  1. Dennis B
    November 12, 2017 at 8:46 pm #

    Mr. Valentino’s presentation brings forward a lot of interesting discussion about a building product that is rarely used in modern construction. Although it can be stunning and do a great job at accenting the architecture with amazing detail the product is rather outdated and can be done much more efficiently with the newer technologies we have available today. That being said it is still extremely important to understand the construction of structures using this material as many historic and well known structures use this as a material and as they age will need more attention to repairs.

    Mr. Valentino made his point very clear that in order to provide the appropriate remedy for any failure the root of the problem must be found. In the case of terra cotta and many other masonry products tension is a likely cause of the failure and this can be caused in a lot of ways. The most common of these tension failures is due to water and moisture infiltration into the terra cotta that begins the corrosion of the steel suspension systems within the material. This corrosion causes the steel to swell and put the masonry material into tension and therefore crack. This is the case in a lot of terra cotta failures and because we know this we are able to develop a solution to this problem. That is to prevent moisture from entering the terra cotta that causes the corrosion, and when it does make its way into the system provide weeps to drain the system around the steel suspension system.

    With new developments in the protection of steel against corrosion there are ways to help prevent these issues from reoccurring after repair. However in new construction terra cotta is normally not the preferred building material as it has become more expensive than other materials.

    It is easier to notice terra cotta in our everyday lives now after our discussion with Mr. Valentino. I have been able to find terra cotta located on the Carnegie building, the Old Botany Building. I also know that the roofs of the Armsby and Weaver building use terra cotta tiles. The HUB addition project also used a terra cotta facade.

    • Richard T.
      November 13, 2017 at 6:32 pm #

      Dennis, I agree that terra-cotta is getting quite expensive these days. Do you think terra-cotta can be used in a modern setting? Why do you think it’s not as popular? Mr. Valentino said that terra-cotta is quite durable but compared to modern alternatives is that still the case?
      You bring up an interesting point about the materials used for repair. How the use of stainless steel as a replacement for what was there before. In a way what’s being placed in the building is of higher quality. Maybe the repair calls for such high-quality materials because it ends up being a weak point in the system. That if the system where to fail again it would fail in the same place. Why would you put better materials in the repair when rest the building isn’t gonna last as long? If you do a repair that last 10 times as long as rest of the buildings life is it worth it to put high quality materials? Why is the repair material better than what would be in the new building construction?

      • Keunhyoung Park
        November 13, 2017 at 11:45 pm #

        Richard, I am interesting your question that why there a few of Terra-cotta in a modern building. I think the building in these days does not have to express some story or identity by using Terra-cotta to include some typical symbol or shapes. Even when they need to set a symbol sculpture or pattern on its wall, there are more advanced modularized panel which is more easy to use. Furthermore, as we seen previous class, installing Terra-cotta by penetrating to wall may be weak point of moisture or air barrier of a building.

  2. Geoffrey T.
    November 12, 2017 at 3:17 pm #

    First of all, I would like to thank Mr. Valentino for his time on Tuesday. Mr. Valentino gave a very valuable lecture on Terra Cotta preservation. In his lecture, there were 3 main topics that he discussed: identification, cause of failure, and repair process. Mr. Valentino used a lot of case studies, which helped me to understand how to differentiate terra cotta with natural stones and possible cause of failures. Similar to other enclosure failures that we learned throughout the semester, water intrusion is one of the major cause of failures in terra cotta wall. Most terra cotta systems are not load bearing. Terra cotta is a lightweight façade system that is used to mimic natural stone. Thus, terra cotta façade is usually anchored to the structural wall with mild steel. When water gets into the system, it will cause the mild steel to rust, causing it to debond from the terra cotta. This debonding causes the terra cotta to crack, shifting the load path of the system, causing the failures to worsen. In one of his case studies, Mr. Valentino showed how water intrusion caused the steel to be completely decomposed.

    One of the biggest challenges in preserving terra cotta system is to ensure that the restoration matches the existing system as close as possible. Mr. Valentino shared with us the importance of the mold and how it could affect the restoration process. Masonry shrinks over time. Thus, if the manufacturers build the mold to be the same exact size as the sample, there is a chance that the finished product will not fit in the field as it already shrinks. To account for the shrinkage, the manufacturers build their mold 10% larger than the sample.

    Overall, I really enjoyed the talk by Mr. Valentino about terra cotta preservation.

    • Dennis B
      November 12, 2017 at 8:52 pm #

      Geoffrey,

      I thought this was very interesting as well. I found that the restoration process for some of his case studies were very extensive. It would be interesting to see how more of these restoration projects could be done using more modern technology. Although some terra cotta projects last an extremely long time, i believe there are more modern materials available that are light weight enough and can mimmic the same characteristics as natural stone and terra cotta. I would like to know more about how these materials that replaced terra cotta could be used in the renovation process to help keep costs lower for clients and still maintain the appearance and longevity that terra cotta provides.

      • Geoffrey T.
        November 13, 2017 at 7:07 pm #

        Hi Dennis,

        I’m not exactly sure about the materials since the reason why people go to terra cotta in the first place is to substitute the expensive natural stone. Reasons why natural stone are expensive is not only caused by the labour alone, but also the transportation. Even though terra cotta is a lot cheaper compared to natural stone, the manufacturing process (color matching, mold creation, etc) can be expensive, since there are not a lot of companies that offer masonry preservation. I think one of the ways to increase the efficiency of the mold creation is to use 3D printing. With the current technology, we can pretty much print anything in any shape (there is a case study where construction company 3D print a house with concrete material). So, I think that we can also 3D print any parts of the terra cotta facade that require restoration. In terms of materials, I think we can maximize the materials’ composition that will give the client maximum performance with minimal costs.

        3D print house: https://www.youtube.com/watch?v=GUdnrtnjT5Q

        • Perry H.
          November 14, 2017 at 12:32 am #

          Geoffrey,

          If I remember correctly Mr. Valentino said that back when terracotta was first starting to be used in the 1890’s it was a cheaper alternative to natural stone which is why it became popular. However today natural stone is cheaper, this is why repairing terracotta can be so expensive if large quantities of blocks need to be replaced. The idea of 3d printing the replacement blocks sounds like it could be a very effective solution to this problem. I found this project built by architecture department at the University of Hong Kong where they 3D printed about 2000 bricks all of different size and shape and completed the project in three weeks. This is a huge improvement since the only way to mass product terracotta is if the blocks are the same size so that a mold can be used over and over.

          https://3dprint.com/187577/3d-printed-pavilion-hong-kong/

    • WangjaeY
      November 13, 2017 at 7:47 pm #

      Geoffrey,

      I also enjoyed the lecture by Mr. Valentino. I noticed that the restoration of the existing terra cotta is very hard to accomplish as Mr. Valentino explained. It looks like most of restoration works caused by the water damage to the steel that constructed long time ago. However, I am sure that the newer application of terra cotta would take a advantage of using newer materials or application to steel to prevent the corrosion in steel. It would last longer to maintain and reduce the chance of failure in the future.

    • Jared P
      November 20, 2017 at 9:00 am #

      I agree the restoration use of Terra Cotta is very interesting. The process behind as you mentioned is very important to bring to light when talking with clients who don’t understand why Terra Cotta restoration can be expensive. Modelling the molds is often done by scratch for every unique shape. The cost can be exponential as the variety of pieces increase.

  3. Megan F.
    November 9, 2017 at 5:41 pm #

    Mr. Valentino’s presentation was very interesting and informative. He gave us good insight into terra cotta as a building material. Terra Cotta used to be used as a lighter and cheaper alternative to natural stone however, it has been decreasing in popularity over time. Mr. Valentino provided examples of terra cotta failures and repairs. It is interesting because water is the common issue with terra cotta like many of the other materials we have studied so far. Back when terra cotta was widely used, proper flashing and waterproofing techniques were not used. This has caused many problems with the historic terra cotta on buildings. Once the water gets into the façade, it will cause the rebar to corrode causing the terra cotta to spall. Many of the facades of historic buildings are not maintained well so the required repair can be very costly. A lot of times the repairs are short term but ultimately prove ineffective creating a larger issue in the future. It is important for the terra cotta to properly be repaired to ensure that the problem won’t arise again. I am surprised that the owners of these beautiful historic buildings allow the short term repairs that are not aesthetically pleasing and effective.

    • EllenW
      November 14, 2017 at 12:14 am #

      Megan,

      I think that it is very interesting that even though waterproofing and/or flashing was not used during the initial construction of terra cotta facades, they have lasted a long time before having serious structural issues. Modern curtain wall facades can have water infiltration issues within a few year of construction, but the terra cotta has lasted for 80+ years before needing to have the embedded steel bars replaced. I think this shows high durability of terra cotta as a weather resistive building envelope component.

      • Shangmi X.
        November 14, 2017 at 8:59 am #

        I am very agree that terra cotta is a very durable material. This remind me about the historical monument “Terracotta Army” in China which is a collection of terra cotta sculpture from the third century BCE had been buried underground. It is a very long time for terra cotta to last. Although the color are all disappeared but the general sculpture are all in a good shape. This really shows that terra cotta is not only free to form any shapes but have a very long durability.

  4. CamilleS
    November 9, 2017 at 11:24 am #

    I really enjoyed learning more about decorative terra cota on facades from Mr. Valentino’s lecture. There is obviously a lot of detail orientated issues with existing terra cotta anchorage, deterioration, and replacement that takes experience and knowledge to correctly tackle. I think it was very informative how Mr. Valentino compared some “fixes” done by non professionals with terra cotta issues, such as trash bag netting and wire supports, that are non sustainable repairs but may become long term. I though it was super interesting to hear more about the manufacturing of replacement terra cotta and how few manufacturers there are anymore. That means that each piece of decorative terra cotta is that much more valuable to not just the historic fabric of the building, but from a monetary value as well.

    I don’t believe there is decorative terra cotta per say on Old Main, but I do believe there is structural terra cotta in the floor system. I have seen terra cotta blocks used as infill in concrete slabs in historic buildings before. I would have loved to learn more about the use and the rehabilitation of failed structural terra cotta. Even from a load analysis perspective I think it is a very interesting historical structural system to learn about, since we don’t design structural terra cotta floor systems in modern building.
    Otherwise, I hope to be able to at least identify terra cotta elements in buildings now, instead of getting duped into thinking it is real stone elements. I appreciate having the opportunity to learn more about this historic material.

  5. Jared P
    November 9, 2017 at 8:50 am #

    I was very interested with Erik Valentino brief presentation on terra cotta. It was a vague topic of discussion for me before I heard this. I am familiar with cast stones being used to mimic stone facade and terra cotta is more or less the predecessor of that technology. I have had experience detailing cast stone projects in my internship. From what I took from Mr. Valentino’s presentation, the differences in the two material is the manufacturing, cost, and quality.

    Both cast stone and terra cotta are made from a mold; however, terra cotta like brick is cooked with heat to achieve stiffness where as the cast stone is concrete that cures. This difference effects the expansion properties, over time terra cotta will gain moisture, cast stone will lose moisture. Cast stones are typically one solid extrusion into a mold but terra cotta is cooked as hollow shell with inter webs to give stiffness. The terra cotta, while it was far less expensive than stone, is still relatively costly compared to cast stone. The true benefit of Terra cotta is the variety of chromatic color schemes you can do with the glazings which are more unique than what cast stone will produce. Terra cotta will stay in the industry because I think there will still be a project, new or restored, in the future that will want the look only terra cotta can give.

    • David K
      November 13, 2017 at 10:39 pm #

      Jared,

      I also see a place for terracotta facades in the current industry, however, I question the extent to which it is used. Historically, terracotta was used for large components of a facade such as a cornice or column capitals. The details that were shown in the presentation suggested that terra cotta was used as bulk elements supported by steel members within. In the current industry, since we have moved away from mass masonry, do details show terra like brick veneer wall construction or as more traditional construction as seen in these historical details? One could take many factors into this question such as current day cost, constructability, and resistance to deterioration.

  6. benP
    November 9, 2017 at 8:47 am #

    I found the reasoning that Terra Cotta was used to be the most interesting part of the presentation. Terra Cotta is lighter and in the era was cheaper to make. A lot of Terra Cotta is made with hollow cores to cut down on weight. This helps the people handling it and the structure has to resist less load. I did not realize that it could come in so many colors and forms. Since the presentation I will now look at all masonry type structures to try and determine if it is Terra Cotta. I wish he would have covered more of how the Terra Cotta is made and installed. Perhaps at some point in industry I will come across some of this and learn more at that time.

    • Pete Pitilis Jr.
      November 10, 2017 at 12:20 pm #

      I agree, Terra Cottas use was very interesting. The lighter/cheaper material and the ability to create molds really improved the construction process which made the product very efficient. The fact that Terra Cotta comes in so many variations of color/finishes really set the standard for design. Although the complex designs later led to expensive repairs. I too would like to learn more about the manufacturing and installation process.

  7. HarryB
    November 9, 2017 at 8:42 am #

    Mr. Valentino’s terrocotta lecture focused on failures and repairs of terracotta. I noticed many similarities of the techneques talked about in the lecture are we heard from other professionals. For example, the water keeps reappearing as the number one enemy and cause of failure in buildings.
    Another similar theme is the difference between a good repair, a temporary repair and a bad repair. From Mr Valentino’s lecture it seems that what sets a good repair apart from the other two is a understanding of the existing terracotta and its mode of failure. Therefore a good repair often takes a much more methodical approach than a bad one. Some of the repairs require new structural tie ins for the terracotta. If a repair in an older building requires an new tie in how do you know the existing structure can handle the new weight?

    • benP
      November 11, 2017 at 4:47 pm #

      Water seems to be a common agent in making structures and facades fail. But, one must not forget what MKP calls a load: EXPANSION. The following is a link to an article that states the following: “The National Terra Cotta Society published substantially different standards for installation between 1914 and 1927 after finding that initial recommendations did not adequately account for expansion, structural support and water migration” So my question is, can we go back into these old structures and correct these problems efficiently?

  8. Shangmi X.
    November 9, 2017 at 7:47 am #

    From the presentation provided by Mr. Valentino, I learned about the special material Terra Cotta. It a material made from enriched clay mixture and fired at high temperatures with surface glaze. There are many advantage about this material that It has lighter weight than the nature stone. And it is adaptable to ornamentation with many colors and forms. Sometimes terra cotta can be hard to be recognized from just looking at the building surface. Terra Cotta became a popular material which is a cheaper alternative from nature stone long time ago. However, now it is an expensive material for building facade and failures happen on old buildings. Failures are mostly due to the water infiltration and steel corrosion. Then, the building failure will occur when the terra cotta shifts and cracks which will change the loading path where terra cotta cant carry the load. Therefore, it is very important to have good repair of terra cotta.

  9. Tyler J
    November 9, 2017 at 7:31 am #

    Terre Cotta is one of the many topics discussed in this class that I knew very little about prior to this presentation. According to the lecture provided by Mr. Valentino, Terra Cotta is essentially “cooked earth”. Prior to this presentation, I was familiar with terra cotta garden pots and terra cotta roof tiles but had no idea how prevalent Terra Cotta is in architecture today. I also found the history of Terra Cotta interesting. Popular in the early 1900’s Terra Cotta is used to look like stone at a fraction of the cost. Terra Cotta is also often used because of its light weight relative to traditional stone.

    Terra Cotta is almost indistinguishable to the untrained eye. I am certain I have been fooled on many occasions in thinking that a façade is stone, not Terra Cotta. This material can be glazed with an unlimited amount of colors and textures. However, looking only at the glaze of a façade is often misleading. To determine if a material is indeed Terra Cotta, one must find an area that is cracked or chipped to see the base of the material.

    I also found the variety of repair techniques, both good and bad, interesting. As a person with little knowledge of Terra Cotta repairs, I can understand why the common person would simply use a wire or glue to “fix” a failure. Correct repair to Terra Cotta requires extensive knowledge as evident by listening to Mr. Valentino speak.

    It did appear however that often these “fixes” may fix a problem in the short term, but only cause additional problems later. This was evident by the example that used grout to fill a crack in a Terra Cotta façade, but did not maintain the joint between the original pieces of Terra Cotta. While this did fix the immediate problem, it only creates additional problems in the future. Similarly, there was an example where an eagle wing failure had been “fixed” by netting. While this does prevent the wing from falling off the building, it certainly does not look as the architect originally designed the building.

    • JeremyS
      November 13, 2017 at 8:47 pm #

      Tyler,

      I, like you know very little about terra cotta and I appreciate how both of us acknowledged our ignorance. I agree with you statement that terra cotta requires extensive knowledge not only to recognize but to repair. However it seems as though the bad repair jobs we saw in Mr. Valentino’s lecture were more cover ups and repairs. In my opinion they did not look like they had any intention of fixing the problem. To expand more on what you said about the short term repairs creating long term problems; I think that’s when the problem can’t be covered up anymore and that when an owner will call someone like Mr. Valentino to come and fix it. Overall it seems as though many problems in terra cotta and perhaps building envelopes in general just get covered up into the problem become too much to ignore.

      • CamilleS
        November 13, 2017 at 11:11 pm #

        I believe you can tie back this point that Mr. Valentino made in his lecture that you reference above to the same point made by Mr. Pirro in his lecture on concrete deterioration and repair. Owners that may not realize that just by fixing the visible problem, they are not solving the root cause of the failure. Over time instead of making the initial repairs that may be more expensive at the time, they are causing further deterioration of the structure, or the terra cotta facade. In case studies shown by both Mr. Valentino and Mr. Pirro, minor issues that are untreated throughout the years become major problems that require very costly repairs. In concrete, it could require the demolition and repair of entire floors, and in terra cotta it could require the dismantling of an entire facade followed by rebuilding the structural back up and reordering new terra-cotta pieces.

  10. Keunhyoung Park
    November 9, 2017 at 1:07 am #

    There was the lecture about Terra-cotta was delivered by Mr. Erik Valentino from Masonry Preservation Services (MPS). It was so informative time since there were so may valuable knowledge from various project cases he has experienced.

    First of all, I felt shame at that I have not heard about Terra-cotta. Although there are so many building has its Terra-cotta facade, most people has no idea what is going on its inside, even engineers in architectural engineering fields. And I was the one of the people has any knowledge about Terra-cotta system. Mr. Valentino shows so the principles in the working for Terra-cotta’s repairments very easily. I appreciate his kind and humorous explanation such as he talked to the people has no background in the field.

    Terra-cotta has the advantage of cheap price, free-form shapes, light weight, and durability. However, due to some failures of Terra-cotta in early twentieth century triggered off diminishing its using. That is the reason why we can see that most Terra-cotta facade are belong to old aged buildings. And the other reason why more precise and delicate techniques are required to repair them than other systems.

    The other interest thing in the lecture was variety failure types of Facades are related to the corrosion of embedded steel. From many courses including AE537 take the count of preventing water infiltration to the building system. Most of the failures of Terra-cotta showed at the lecture also suffered from them.

    Lastly, fixing of Terra-cotta has more sensitive and accurate process than I expected. Especially, considering volume shrinkage while its baking to fabricate the Terra-cotta to main structure precisely in improving manner.

  11. Shubham K.
    November 8, 2017 at 11:10 pm #

    Mr. Valentino’s presentation on terra cotta was very interesting and informative. I learned in great depth about terra cotta and was surprised by the wide range of buildings it is used on. It was also interesting to learn how is made about 15-20% larger than the original size as it shrinks during the process of drying. Most of the failures are caused due to rusting in supporting steel from water infiltration, which is caused by poor built quality and poor maintenance.
    As mentioned by Mr. Valentino, recreating terra cotta pieces is an expensive process. I was wondering, if there is a cheaper alternative to replace terra cotta?

    My guesses on on-campus terra cotta buildings are Old Botany, Carnegie, Sparks, Burrowes building

  12. David K
    November 8, 2017 at 11:06 pm #

    The lecture that Mr. Valentino gave to the class provided an introduction to the repair and restoration of terra cotta building facades. Personally, I believe this provided the class with a much better understanding of what exactly the material terra cotta is, its uses, and its current popularity in the construction industry. This lecture has given the class the insight into identifying terra cotta facade materials versus similar materials such as natural or cast stone.

    Some of the benefits of terra cotta that Mr. Valentino spoke of included material weight and the ability to produce large quantities of identical facade elements. The material itself has a much smaller density than that of stone therefore when the use of terra cotta was popular, it was easier to handle and build with. Since the material can be formed in a mold, it is easy to create large quanities of idential facaded features compared to carved stone.

    • David K
      November 8, 2017 at 11:15 pm #

      continuation of above post:

      When terra cotta was popular, it was inexpensive to produce and was therefore used for large portions of building facades. In modern day, this material is very expensive and not practical to construct entire building facades of, rather it is more commonly used for the replacement of deteriorated terra cotta units.

  13. WangjaeY
    November 8, 2017 at 10:24 pm #

    It was great opportunity for us to have Mr. Valentino’s lecture on Tuesday. As he mentioned, the materials he covered were not the stuff that we cannot get from other classes. I was never thought of many stone works as terra cotta since I have not exposed to learning terra cotta. It was great to learn the detail framing/structure of terra cotta application. Like other failures, terra cotta is very susceptible to water since the framing/supporting structures are mostly steel/metal. It is critical to prevent the corrosion and water infiltration into the structure. It was very informative that cost of installation of terra cotta is cheaper then natural stone work. However, it requires great maintenance to prevent expensive repair. I would like to learn more about how expensive the repair and maintenance of terra cotta after initial failure compared to natural stone work. I also remembered during the site visit for masonry class that apartment in Bellefonte used the cornice made out of the polystyrene foam with painting, not terra cotta. I thought this was interesting way to imitate the natural stone work. After the class, terra cotta is catching my eyes closely now.

  14. EllenW
    November 8, 2017 at 9:55 pm #

    The Terra Cotta lecture given by Mr. Valentino was very informative. I know that terra cotta was used for elaborate architectural details and features on buildings, but I did not know that the glazes could be so varied and colorful. I also found it interesting that the dome on the roof of the PA Capitol is made of terra cotta glazed to look like aged copper. I live near Harrisburg and until Tuesday I would have said that the roof was copper.
    I was wondering, what are the possible bisque colors for terra cotta? I am familiar with the red/brown of a standard terra cotta flower pot which matched Mr. Valentino’s samples. It this the only possible color with the type of clay required or is it just the most popular?
    Thank you Mr. Valentino for taking the time to speak to the class as well as showing us the staircase construction for Old Main.

    As far as campus buildings with terra cotta, my best guesses are Carnegie, Weaver, Armsby, Steidle, and Sparks.

    • Tyler J
      November 9, 2017 at 7:56 am #

      Ellen,

      I too was amazed at the variety of colors and textures that Terra Cotta can become through glaze. I also found the term “bisque” as Mr. Valentino mentioned it interesting and a term I was not familiar with. In doing some research, it appears that the term bisque is a specific type of unglazed porcelain. Similarly, biscuit (in reference to pottery) is any type of pottery that has been fired but not yet glazed. As Mr. Valentino mentioned, in order to determine if a material is indeed Terra Cotta, one must look beneath the glaze to see the bisque. This doesn’t completely answer your question, but I believe there are many possible bisque colors depending on the base material that is fired prior to the glaze being applied. Bisque refers to the initial firing process and thus the interior of Terra Cotta.

      I remember creating clay mugs in middle school. We first formed the mug out of the clay, then placed it in the kiln. After several days, we were then able to apply the glaze and again place the mug into the kiln. The bisque color of that clay was different than some of the examples in Mr. Valentino’s presentation. I do not know if this was because we were making mugs instead of buildings, but I would guess the process is similar and the unfired clay can be modified to create the physical properties desired from the fired, unglazed pieces.

  15. JeremyS
    November 8, 2017 at 6:49 pm #

    Mr. Valentino’s presentation, like many presentations, was extremely informative. The lecture gave a more in depth look at the common problems with terra cotta and how to fix those problems. Before the lecture I thought terra cotta was like any other architectural stone in that you had to sculpt it. I didn’t know that terra cotta is similar to concrete, meaning that it can poured placed and cast. This is most likely why it was so desired because if you have similar cladding elements the design and construction becomes modular and thus inexpensive. Unfortunately like concrete terra cotta can crack and spall as a result of water intrusion. According to the preservation brief 7 terra cotta, in its heyday, was thought to be a “highly waterproof material”. It was not surprising hearing from Mr. Valentino that 30 years after the terra cotta craze there were issues deterioration. There was however a published booklet (from 1914) that detailed some ways in which to reinforce terra cotta assemblies. Unfortunately time and water intrusion has caused issues with most terra cotta elements and thus repairs need to be made.

    One of the last topics that Mr. Valentino talked about was how to repair terra cotta. The bulk of the methods described were managing the way water interacts with the terra cotta and, similar to concrete, protecting the reinforcing steel. Thus I think terra cotta repair is very similar to concrete repair. The main difference between the two is the level of ornamentation and detail that is more common amongst terra cotta than concrete.

    My guess as to the three buildings with terra cotta are
    -Millennium Sciences Complex
    -Hub expansion
    -Botany Building

  16. Richard T.
    November 8, 2017 at 9:36 am #

    I want to thank Mr. Valentino for coming to campus and lecturing about terra-cotta and its use in the industry. From his lecture one can truly see that he is well-versed in this topic.

    One interesting point within his lecture that I’d like to mention is how he taught us to identify terra-cotta opposed to other stone materials on the building. Although most owners prefer their buildings to be cladded in stone, terra-cotta can achieve a lot of the visual features that natural stone can. This can be done for relatively cheap and looks almost the same.

    I was amused find that most architects can’t tell the difference between terra-cotta and natural stone. The fact that they specify a stone repair when it’s actually terra-cotta repair is very interesting. Mr. Valentino mentioned that to tell the difference between the two all you do is look underneath the surface. From the outside terra-cotta looks a lot like natural stone, but if there is a chip in the material it will reveal discoloration and from there you can tell that it’s not actually stone.

    I also found his talk on terra-cotta repair to be very interesting. The fact that most owners find that netting is a permanent repair is also intriguing. I think it’s should be the responsibility of the owner to fix the building as soon as they can. To leave a piece of netting up for 10 years or more sounds ridiculous. I understand that repairing masonry is very costly due to manufacturing custom pieces, but this is something you have to take into account when you take on a venture of this magnitude. Otherwise, I learned today that there are imbedded steel rods in a lot of masonry pieces that hold them to the building. If the rods were to rust, necessary repairs would need to be taken right away.

    One last note. I enjoyed the overall presentation from a visual standpoint and I think that it’s implemented in a way where you can explain to people who are not well-versed in buildings about why certain things have to be done in order to fix them or why you have to fix them in the first place. I hope that Mr. Valentino can come back in the future and teach the students about masonry and terra-cotta in the building industry.

    Of the buildings on campus that use terra-cotta, I only know of the recent hub expansion.

    • Nick S.
      November 9, 2017 at 8:40 am #

      Richard,

      I agree with your initial statement about identifying Terra Cotta as a facade component. I can say I was guilty of not know what Terra Cotta was and would not of been able to tell the difference between it and natural stone. I also agree that this can be said for many people, as we heard and saw from the various examples of incorrect fixes. This just shows that people don’t understand how to handle and install Terra Cotta. On my construction project the masons we are using do not work with this material because of the complication it brings. Overall Terra Cotta is an extremely nice finish to a building envelope, you just need to be sure that you have the proper details, installation techniques, and the money to pay for it.

  17. mkev
    November 7, 2017 at 4:57 pm #

    As I am sure you will agree, a lot of great information delivered by Mr. Valentino this morning that you would not be able to easily compile on your own. As a follow up to the talk, including the item on how to confirm you have Terra Cotta, I am challenging you to find / name the Penn State buildings that have Terra Cotta or other clay tile products mentioned in the lecture. Hint: There are at least three that have historical architectural Terra Cotta features, one newer / modern application and several with Ludowici or similar clay tile roofing. Post your answers on this site and I will add hints as necessary to keep the challenge going. Prize to the winner.

  18. Nick S.
    November 7, 2017 at 2:56 pm #

    On Tuesday, November 7th, the AE 537 Building Failures class had the pleasure to hear a presentation by Mr. Erik Valentino. Mr. Valentino is a Penn State graduate from the Architectural Engineering (AE) program. Currently, Mr. Valentino is working for Masonry Preservation Services, Inc. (MPS) where he is Vice President. Mr. Valentino handles corporate and client development, field studies to evaluate building envelope deficiencies and failures, development of repair recommendations, and implementation and management of remediation efforts for MPS. As a company MPS specializes in architectural maintenance and restoration.

    After Mr. Valentino gave a brief introduction began to discuss his presentation topic of Architectural Terra Cotta Facades. This presentation consisted of four (4) main topics of Terra Cotta; rationale, evaluation, failures, and repair. The first portion, rationale, gave us a short background on the use of Terra Cotta as a facade component. I found this to be an interesting way to start the presentation because I never realized that Terra Cotta was once an inexpensive material. The second, evaluation, looked into the forensic evaluation of existing Terra Cotta facade assemblies. Third, failures, went through a variety of areas/way Terra Cotta facade assemblies fail. Finally, repair, went into the restoration/preservation techniques.

    Overall, Mr. Valentino gave an extremely informative presentation on a material I did not know much about and one of the main points that really stuck was how important it is to divert the water out of the envelope. This is something that Mr. Valentino stated repeatedly throughout the presentation and showed a variety of different photos showing the failures that occur due to water infiltrating the envelope. A second topic the stuck with me after the presentation and reading “Caring for Glazed Architectural Terra Cotta” by Hoffman Architects Journal (see link below) was how too often improper repairs are done. Both the article and Mr. Valentino stated that owners bring in contractor who try to fix the issue, but in reality are just putting a “band aid” on the problem. The article states “Often, repair materials are not durable and are incompatible with the existing Terra Cotta, creating a poor visual match and a short-term fix, at best. Where repairs fail, they tend to make deterioration worse.” These types of fixes make you wonder why as an owner you would be allow for this to take place? These incorrect repairs end up sometimes costing more than what a proper repair would. It seems that so often people look for the quick fix instead of taking the time to correct the issue the first time, especially when fixing and issue in the building envelope.

    Another interesting item discussed in the article was the replacement materials that could be used to substitute for Terra Cotta. These include precast stone, glass-fiber-reinforced concrete, glass-fiber-reinforced plastic, and micro-cotta. Each of these has benefits and concerns that need to discussed before being implemented.

    In conclusion, Terra Cotta is a building envelope material that is no different than any other. It requires proper installation and maintenance on the part of the contractor.

    Article URL: https://www.brikbase.org/sites/default/files/Journal-Vol-32-N1-Terra-Cotta-LOW-RES.pdf

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