Wall Water Barriers 101 – 2016

Emily Wychock, P.E.,  a Penn State AE alumnus, continued the tradition of presenting a Simpson Gumpertz Heger (SGH) lecture on the topic of waterproofing and water management to students in the Building Failures and Forensic Techniques class in Architectural Engineering at Penn State.  This year the title is Wall Water Barriers 101, a follow up to the traditional and highly popular Waterproofing 101 seminar of the past.  This is the longest running visiting practitioner seminar in the AE 537 class.    Ms. Wychock covered the fundamentals as well as showing a number of case study  examples of her projects to reinforce the various lecture points.  Ms. Wychock covered design, construction, material defects and maintenance issues in her discussion.

Students interested in information that complements the SGH lecture may also want to look into some of the resources recommended by Michael Palmer, Building Envelope Specialist with Dow Building Solutions  who has lectured and consulted with AE  537 in the past.  Mr. Palmer recommends the following links for more information on wall control layers and related topics.

Another excellent resource recommended by Professor Parfitt related to this topic and building envelope design and  failure review in general is the Whole Building Design Guide.  More specifically, it is the Building Envelope Design Guide that relates to waterproofing.  The Building Envelope Design Guide is an excellent reference for this discussion post but it does cover a lot of ground from a topic perspective so you may have to be selective.  On the flip side, adding and relating information to this discussion should be fairly easy due to the amount of information in the guide (and associated references).  Students are encouraged to incorporate information from other sources as well as long as it has a bearing on the discussion.

Another good set of references that go into detail on a number of the items mentioned in the lectures, particularly the physical construction and inspection of wall systems are the  Brick Industry Association (BIA) Tech Notes.  In particular:

BIA Tech Note 7: Water Penetration Resistance – Design and Detailing BIA Tech Note 7b: Water Penetration Restance – Construction and Workmanship BIA Tech Note 7a: Water Penetration Resistance – Materials

The BIA documents explain some of the unique issues related to cavity wall construction that were mentioned briefly in class during our discussions and campus search for mass masonry wall structures.  This reference will be revisited by MKP later in the semester during the planned lecture on masonry movement joints.

Additional Related Publications for Background and Discussion

Two publications that also relate to this discussion topic of interest are:

Fleshing Out Flashing Options,” by Derek B. McCowan, PE, The Construction Specifier, November 2011.  You need to open and use / click on the icon for the article in the table of contents to skip to Page 18 for the full article.  The author is from SGH.

Flashing from the Masonry Perspective” by David Sovinski and Patrick J. Conway, CSI, AIA (both authors from International Masonry Institute), The Construction Specifier, February, 2008.

Built-in wall flashings– through-wall systems and the like– are often modified, reduced in quality or even partially eliminated as part of the value engineering (VE) process. Although these hidden components add little to the building’s visual appearance, wall flashings are essential parts of its weather protection system. Decisions made in the name of VE often provide very modest monetary savings when compared to the resulting degradation in reliability and durability.  That said, many field problems in this area are a result of installation problems or poor detailing…sometimes all of the above.

Featured Photo for this Post:

The featured photo for this post is the IST Building (Soon to be renamed Westgate) on the University Park campus of Penn State.  Investigation of brick facade problems for IST by a forensic firm in conjunction with the Penn State Office of Physical Plant (OPP) revealed primarily construction related problems.  You can easily see from the photo or simply by viewing the building facade that the cost of repair of simple items such as brick shelf angles and flashing etc. is extremely disruptive and costly.  Although you can’t tell from this photo, I believe that in at least some areas, the waterproofing and flashing continuity was disrupted and the flashing did not extend through the brick face…all items that Ms. Wychock warned you about as typical problems in maintaining a properly functioning cavity wall.

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43 Responses to “Wall Water Barriers 101 – 2016”

  1. YusufA
    October 3, 2016 at 9:29 am #

    Comments on here has not only given me an understanding of the topic being discussed but also points to various issues which are being faced in the building industry which I may or may not already be aware of. Failure in construction may necessarily not be immediate or obvious but most of it can still be prevented during construction.

    I can imagine in this particular case, unless the construction job is being done and supervised by a Biologists for instance rather than a Building Engineer, Failure due to the movement of water from the exterior wall face to the interior of a building will occur slowly over the life span of the building and therefore will be unexpected.

    In previous comments, it has been widely accepted that a proper installation of the barriers and flashings is key to the avoidance of this. It may be very important to take note and put the supervision of this installation in the hands of well-trained operatives and this may not necessarily be a single individual as also mentioned by ‘Joe’ in his comment. This could add an extra cost and time to construction but would go a long way into avoiding the failure due to water.

    At the same time, there are several materials manufactured for this barrier purposes and knowledge and experience is needed in order to decide on the right material for a job site. I would believe that several factors are needed to be taken into consideration which includes but not limited to the function of the building, Climate of the building region and the climate at the particular time of installation which I would believe is preferred to be during the dry weather for proper gluing of the barriers.

    Contractors should pay close attention as they pay to structural system construction to this wall water barriers especially at joints to prevent them from having to come and repair at a later date after failure.

    The Whole Building Design Guide, WBDG also has some guidelines with relations to the installation of this barrier systems and in the article ‘Integrity Testing for Roofing and Waterproofing Membranes’ which should guide in testing the integrity of the barriers installed.

  2. Di W
    October 2, 2016 at 11:17 pm #

    After the lecture I have searching some other articles that relates to moisture prevention in building envelops. And I have learned the moisture that forms on condensation planes can be drained away from the wall if the location of the condensation plane is properly designed and appropriate drainage system is in place. However, since condensation can also form on surface (condensation plane) where no drainage system can be used, it is important to consider and design for diffusion drying. Otherwise it is possible for moisture to get trapped and not able to dry out, which can then lead to corrosion, rot, mold, etc.

  3. Yamile R
    September 29, 2016 at 2:31 pm #

    From the presentation, I remember the mention of the perfect wall, and the right way to layer up the walls.
    I took a webinar last year about building science and wanted to share this article about it. https://buildingscience.com/documents/insights/bsi-001-the-perfect-wall
    I like the expression “the perfect wall has to keep the outside out and the inside in”. It gives example of the details, layers, and the ways to build it. Also gives a suggestion on the ideal section for commercial, institutional, and residential use.

    • Yingzhe You
      October 3, 2016 at 12:00 am #

      Yamile,
      Thank you for the reading material. I really love his opinion about the importance of the building envelope-“A point to this importance thing here, if you can’t keep the rain out don’t waste your time on the air. If you can’t keep the air out don’t waste your time on the vapor.”

      The rain penetration is really a big problem. I’ve read some material about the failure of BE. If there is a crack and causes the rain to go inside the house, there will be not only instant damages but also long term damages. The damages of carpet, furniture and other things in the room can be easily seen and repaired, but what is really annoying is that you do not know the condition of the wall. Water can penetrate into the wall and cause long term damage which maybe rot or corrosion. That can be really difficult to be noticed and may take more money to be repaired.

      I also heard of a wall that is described as “wall that can breathe”. I’m not sure if it is one of the walls described in the article.

    • Yemi O
      October 3, 2016 at 8:54 am #

      Yamile,

      Very good read. It is interesting to know that different building assemblies are more efficient/ideal depending on the sector i.e residential/commercial. However, the article states for the “commercial wall” that it “works everywhere in all climates”. As I mentioned in my earlier post, and as Emily confirmed, that may not necessarily be true.

  4. philr
    September 28, 2016 at 12:06 pm #

    Some of you may or may not be old enough to remember the notorious issues with “Dryvit” …which is a foam board used on many homes which looked like stucco. The intent with Dryvit was to provide a stucco look, but do it without the intense skilled labor required to apply traditional stucco finishes.

    In the late 90’s lawsuits relating to Dryvit were in abundance. In short, most experts agreed that the product itself worked well, when applied as the manufacturer dictated, and properly maintained. However, many contractors did not bother learning how to property install the system, assuming that a semi-skilled (at best) labor force could take the materials provided and “figure it out”. All of the lawsuits related to moisture intrusion leading to wood rot in the frames of the homes. Many attorneys made a lot of money over Dryvit in the 90’s, and there are many people in the construction industry that still cringe at the name. However, like we learned in Ms. Wychock’s presentation, the product can be good, but unless it is installed correctly, even the best product can fail.

    Here are some links to Dryvit (also known as EIFS in more general terms) discussions. Please note that some of these references are not necessarily intended to be neutral about the subject.

    https://www.exterior-design-inst.com/eifs-moisture-intrusion-problems.html

    http://www.dryvit.com/home/default.asp

    http://www.nytimes.com/2002/08/18/nyregion/nj-law-behind-some-stucco-like-walls-problems.html?_r=0

    • Yamile R
      September 29, 2016 at 2:22 pm #

      Thanks Phil;
      I agree with what you, Ms Wychock, Rebecca and few of the others emphasize, on being the proper application of the material the most important part of the system. If this is wrong from the beginning, it does not matter the quality of the material, the material can fail.

  5. Prateek Srivastava
    September 27, 2016 at 6:43 am #

    Emily’s presentation was very insightful shedding light on the usage of wall water barriers. It was helpful in knowing that how some small things which people don’t care about much can lead to bigger consequences as improper placement of flashings, window perimeters etc may result in replacement of full cladding.

    She told us about the types of wall, ie, masonry, bearing, cavity walls.

    She discussed about one of her cases on which she had worked, it was a school ‘Waddle Buillding’ where there were leakage issues as the flashings were not properly placed and there were huge spaces/cracks between the walls which led easy movement of water. This case also gave an idea as, being an engineer you can suggest remedies but its the client who needs to decide as in what level of repairs do they want, ie, full, half or nothing. The school decided to do the mid level of repairs according to their budget so as to be safe for a longer time rather than overall restoration.

    She also showed us joints and water proofing sheets which was helpful to physically touch and see the material.

    It was a holistic lecture with physical samples of material present to enhance the comprehension.

  6. Ishan Uppal
    September 27, 2016 at 12:55 am #

    As a Structural Engineer, we look at various parameters that affect the safety and stability of our buildings. Emily Wychock’s lecture was a revelation at how water also needs to be managed within a structural system for the long term safety and usability of the system.

    The lecture was an education introduction to the various kinds of building envelope systems, their various mechanisms, advantages and installation methodologies.

    Seeing as how the building enclosure typically makes up 20% of the new buildings cost, due importance has to be given to its planning and construction. This demands proper knowledge of the detailing and understanding of the wall system. This talk highlighted how the way the enclosure is set up decides how well water is kept out of the system.

    It was very informative to learn about the various types of wall systems, I.e. barrier walls, cavity walls. I wonder how the upkeep and maintenance of a surface sealed barrier wall is done, especially as the joints are sealed with sealants applied into quarter inch gaps.

    The Waddell case study was particularly interesting for me. The water testing techniques using spray racks and nozzles to identify the leak path was something I had never read about before.

  7. Shubham
    September 27, 2016 at 12:48 am #

    Emily’s lecture really enlightened about the necessity of waterproofing.
    Her key points, labelled – ‘Keys to success’ covered several counter-measures of possible problems.

    I think she left an interesting point for us to think upon. How to pick exploratory openings in cladding during an investigation?

    Is there any way to prevent efflorescence without sealed barriers? I mean treating root cause, instead of preventive measures.

    One can conclude, while using fenestration a skilled workmanship is much required.

    • Alec B
      September 28, 2016 at 11:01 am #

      Shubham,

      I did some additional research into efflorescence and ways to prevent efflorescence that don’t necessarily deal directly with sealed barriers. I referenced an article from the Masonry Institute (https://www.masonryinstitute.org/pdf/612.pdf).

      Of course, for efflorescence to appear, moisture serves as the driving factor in which alkali sulfates emerge to the surface. Aside from the obvious of developing efficient and effective architectural details, the Masonry Institute recommends consolidating the grout with mechanical vibration. This reduces any voids in the grout and improves bonding; minimized voids in the grout helps for natural pores in the wall to be reduced which makes it harder for salts to migrate through the wall assembly to the surface. Also, the Masonry Institute mentions grout admixtures that help to inhibit efflorescence. According to the manufacturers, grout admixtures improve the flow of the grout mix while decreasing the water content; this also helps to reduce voids in the grout due to shrinking since less water content is required. Also, dense tooling of the mortar joints also helps to consolidate the grout and minimize pores.

      Another thing I read up on in the BIA Technical Notes related to Construction and Workmanship is parging. I was unfamiliar with parging until reading this article. Parging basically is the process of applying a coat of portland cement mortar to masonry. From what I understand, this covers up the brick which may not be desirable in all cases for architectural reasons, but it may be an option for walls that may not be completely exposed. Parging helps to damp proof which reduces rain penetration and air leakage. BIA recommends that parging the back side of the exterior wythe is not performed for drainage-type walls because debris in the air space is increased which is of course not desirable.

  8. Brendan B
    September 27, 2016 at 12:48 am #

    Emily’s presentation was very informative as building enclosure is something that we haven’t really touched on yet in our classes. It is something that seems to have been neglected even though the enclosure is critical to the overall aging of the building. As we have learned, the roof and facade contribute the most problems towards a buildings structure, and the biggest culprit is water damage to the facade. Flashing is used to help combat this water damage in cavity walls, but does not always succeed.

    This brings me to the point Emily made during her presentation how workmanship is the component of success that is generally ignored the most. It seems that a common theme in this class has been failure during construction of the building, whether its miscommunication between the engineer and contractor, or pressure from the contractor to finish by a deadline. If greater caution was taken during the construction phase, then there would certainly be a decrease in these building problems. However, that is certainly easier said than done when money and time are always priorities.

    • Joshua Z
      September 27, 2016 at 1:42 am #

      Brendan,

      I agree with you that quality of work is extremely important in preventing a failure, and that it is a common theme in our class. Too many times have we seen examples of buildings failing because of poor workmanship and failure to follow shop drawings, as well as miscommunication.

      I also find it interesting how much of an impact the building enclosure has on the structure of a building. We have not learned much about building enclosures and how they impact the functionality and longevity of a building. This is a topic that I hope we get to explore as time progresses.

      • Shane M
        October 2, 2016 at 9:46 pm #

        Josh,
        It truly is fascinating how so much could go wrong with a structure if it is not properly protected from the natural elements. Water, as basic as it is, can have very powerful effects on things it comes in contact with. Mixing water and cold temperatures is a recipe for disaster in many cases, and that applies beyond just buildings. The tiniest infiltration of water in a structure means that there will be more and more water that will repeatedly enter and cause damage in that same location until it is fixed. We want to build our structures to last many years, but if the building envelope cannot perform then this will leave other parts of the structure, parts not meant to see water, vulnerable to corrosion and unwanted fatigue. The effects of water on a wood structure can be the most noticeable because they happen so fast. When wood comes in contact with water it begins to swell up. When this happens, the force of the expansion can be more than enough to loosen the connections by simply pulling them apart. In Walt’s wood design class you will probably discuss these effects in more detail. A little interesting fact about the power of wood swelling goes back to ancient Egyptian times. When they needed to cut large slabs of granite they cut a slot in the granite and inserted wooden wedges which they soaked with water. The wood swelled creating pressure that was able to split the rock. So you can say that water would be a bad thing to see in a wood structure.

        • Brendan B
          October 3, 2016 at 1:01 am #

          Shane,

          It’s interesting how you bring up water’s effect on wood. In fact, we have discussed in Walt’s wood design class that a higher moisture content decreases the strength of wood. This is especially important to consider when designing the building’s enclosure in areas of the country with the highest rainfall precipitation.

          The common theme on this discussion board is questioning why owners are choosing to minimize the cost of the building at the expense of the building’s longevity. If repair/restoration is needed on the facade every 15-20 years, how cost effective is the building actually? When building with wood in heavy rainfall areas, this question is even more important.

        • Joshua Z
          October 3, 2016 at 7:20 pm #

          Shane,

          I agree that it is impressive as to how much damage water can cause a structure. Your note on the effect of water on wood is interesting. I also find it important to note the effect that water has on concrete structures as well. It’s the reason we build foundations a certain depth below the frost line, so that frozen water does not have any up-heave on the foundation. When water freezes and thaws, it expands. Movement of the foundation could have disastrous results, and could compromise the entire structure. Continuous exposure of water to steel members can also cause rust, which weakens the strength of the member and consequently, the longevity of a building. And, as you mentioned, even the smallest amount of water that enters the building can cause a great deal of damage, which is why it is important to catch the problem and fix it as early as possible. I also find your comments on the Egyptians fascinating, as they were some of the brightest minds in history and paved the way for engineering in the future.

  9. MichaelB
    September 26, 2016 at 8:01 pm #

    Emily’s presentation was very informative. It is amazing how many mistakes are made all the time. I wonder if it would benefit the owner more in the long run to pick a higher bid from a contractor who is more likely to install barriers and flashing the correct way to avoid long-term water issues. Most of the costly repairs shown could have been easily avoided if the building enclosures were installed correctly.

    I guess it comes down to how far in the future the owner is willing to look compared to how much he or she wants to save up front.

    • Alec B
      September 27, 2016 at 7:45 pm #

      Michael,

      The involvement/decision-making of the owner is a unique contributing factor of building performance failures in relation to facades/building enclosures. Owners want to minimize cost but at the same time, owners must keep in mind the longevity of the building.

      My dad runs into similar issues all the time with some of his customers in the auto body repair business. Customers will come in with rust on their vehicles in need of repair to stop the rust from “spreading.” My dad’s way of fixing the rust the correct way to minimize the possibility of the rust coming back is often deemed too expensive by owners. While some auto body repairmen will offer a cheaper manner to fix the rust, my dad turns down the work if customers aren’t willing to repair the rust the correct way. The reason being is that oftentimes if the rust is not fixed correctly, it will quickly come back and my dad’s work and business is given a bad name (even if the repair was done with the customer knowing it was only a “temporary fix”). That leads me into an interesting thought: I wonder if (and if so, then how often) contractors turn away work if owners aren’t willing to pay for the solutions that aren’t “half-assed.” I’m sure contractors don’t want to put their name on work that may not perform as well as it should. And I’d imagine some owners may legally go after contractors if “short-term” repairs don’t hold-up as long as the owner would like them to.

      • mkev
        September 28, 2016 at 10:50 pm #

        Can your dad help me fix my 68 mgb? I need it done right!
        Seriously though, good analogy

    • Emily Wychock
      September 28, 2016 at 8:35 am #

      Michael,

      You bring up a couple interesting points. There are good contractors who gain a reputation for producing quality work, without cutting corners in some of the ways we discussed in class. As a consultant, we are sometimes able to make recommendations to owners for contractors that we’ve worked with in the past that we’ve had good experiences with. Unfortunately, as a designer, we don’t always have that luxury and will occasionally run into contractors that require us to keep a much closer eye on things during construction. Sometimes this will lead to bigger disagreements down the road. For example – in my second case study I discussed the windows at balconies that leaked when tested during construction. The investigative work to determine the cause of leakage, the repair work, the re-testing of the windows, and repeating this repair work on all the windows throughout the building is expensive, and is certainly not something the contractor planned on doing. Who do you think is responsible for this extra cost?

      Another interesting point – how far into the future is the owner of a building looking? This certainly plays a role in the design, construction, and how a building is expected to perform. For example, a university that’s constructing a new building on campus that they will own and operate for a long time, is hopefully thinking about how the building will perform 50 years from now. They may put a lot of time and effort into QC during construction. Alternatively, a developer who is constructing a new apartment building and plans to sell the building in 3-5 years probably has a much different mindset.

    • Prateek Srivastava
      October 1, 2016 at 8:15 am #

      Michael,

      As you said, that it depends on the cost cutting the owner is looking at and his/her forsightedness towards the longevity of structure but i feel it also depends on finding the right people to do the work.

      Even for lower costs there are contractors and subcontractors who are knowledable enough to do good work. Owners generally tend to hire people who have higher publicity in the area and who have done bigger projects.

      So, if i am not wrong keeping design and material quality intact when an owner is looking for cheaper options he/she can save money by hiring smaller contractors and getting the whole work done as necessary rather than hiring a bigger contractor and not fixing the problem as a whole and just getting partial work done.

      It’s always good to hire the best but incases of less funding we can always hire second best people as long as their past work records are good as workmanship is one of the key aspects in civil construction.

  10. Shane M
    September 26, 2016 at 4:56 pm #

    Upon entering the structural option I never gave much thought about the importance of the enclosures and building technology side of the industry. I am glad that I have had the multiple opportunities to learn more about this subject. Growing up as the son of a contractor, I have had the chance to do hands on repairs for many single family homes that had leakage issues, primarily in the roof. I have also constructed some exterior walls for these residential structures, so I am somewhat familiar with this topic on a small scale.
    It seems like there are too many cases where the envelope of a building is either constructed wrong or improperly designed. With all of the components that need to come together in order to make a building envelope function properly, there is bound to be a mistake at some point. I would say that most envelope failures are due to constructability issues. If a designer does not have enough experience with building envelope design and construction, then they are easily prone to making unclear or incorrect construction documents. I also believe that time and money play a major role in the downfall of envelope performance. Rushing construction is never good for any part of the building, unfortunately the more complex features like facades are drastically affected by this.

    • Emily Wychock
      September 28, 2016 at 8:39 am #

      Shane – You bring up a good point. As an engineer or an architect, designing something that is actually build-able is key. Physically building something yourself, or seeing it done on a construction site, is a great way to see how what’s drawn in 2D on paper actually comes together, and to understand the difficulties and conflicts people in the field will run into.

    • Rebecca M
      October 2, 2016 at 1:39 pm #

      Shane
      I also didn’t think much on the building technology side of structural engineering until I realized that the repair and rehabilitation of buildings depends greatly on this knowledge. Because the greatest issue buildings have during their lifetime is water penetration, the construction of wall water barriers is incredibly important.
      During the discussion of key points of success in wall water barriers, it was noted that workmanship was the most critical, however like you mentioned, sometimes the design doesn’t come across clearly enough for the contractor to understand. Sometimes it seems like the lifetime of the building depends on what solution the contractor comes up with in the field.
      Because I think we understand the factors that go into the level of workmanship, I decided to review the Brick Industry Associations technical notes on the design and detailing aspect on wall water barriers. It didn’t occur to me that design also included fire resistance, heat transmission, and sound reduction. In addition to knowing the type of wall the building will have, the designer needs to understand the sources of moisture surrounding the building like ground water, wind-driven rain, and condensation. After looking into the requirements of consideration for water resistance, no design can really adhere to the design standards and still perform as expected. Location, moisture content, and other situations drive changes in detailing, which then changes the way contractors understand how it is to be installed.
      While the workmanship of the water barriers is the largest area of concern when installing, the details of the design need to be chosen carefully and explained fully to ensure the contractor achieves the highest level of quality for the lifetime of the building.

  11. Yingzhe You
    September 26, 2016 at 3:49 pm #

    Emily’s presentation was really enlightening. With several cases presented, I can get to know why building envelope failed.
    I took building envelope design course last semester so I started to know what we need to focus on when designing. But when it comes to the actual construction, there are always more we need to pay attention to. The failure caused by improperly installation of flashing impressed me most. I used to pay attention to the condensation problem but never took the path that can lead water out from BE as an important thing to consider. But if the flashing length or angle is not appropriate, there will be big problems. So I really appreciate the chance to study actual failure cases after learning the theoretical knowledge.

    • Di W
      September 26, 2016 at 8:16 pm #

      I agree with you.

      Before listening to this speech, I only knew theoretical ways of controlling the moisture such as if whatever moisture enters the assembly leaves the assembly, moisture cannot accumulate and potential problem can be dealt with easier; on needs to consider the extent and duration of wetting, storage and drying in order to evaluate the potential of moisture damage; conventional moisture control strategy consists of reducing the amount of wetting by increasing air tightness, vapor resistance, reducing the volume and rain water penetration, and absorption. Now I have learned ways that are basically used in industry like those different protective materials and the reasons of failures in moisture control.

  12. Yemi O
    September 25, 2016 at 7:18 pm #

    Emily’s lecture was very informative. Prior to this talk, I never gave much thought to water leakages through building exteriors, how they are caused and even how they could be prevented or limited. I found it interesting that something that seemed trivial such as missing or badly designed flashings could affect a building very negatively and could even cause problems with the law.

    However, what I really started thinking about was how these different materials used for vapor retarders, cladding, etc, work together under different climatic regions. For example, would the same building assembly used for a building in a hot and humid climate be as efficient in a cold climate?

    • Emily Wychock
      September 28, 2016 at 8:56 am #

      Yemi – Great question. The quick answer is no, the same exterior wall assembly does not necessarily work in every climate zone. You can imagine that in Alaska the majority of the year is spent heating buildings (warm on the inside, cold and dry on the outside), where as in Florida the majority of the year is spent cooling buildings (cool on the inside, hot and humid on the outside). Pennsylvania is more of a mixed climate, we have both heating and cooling. The correct placement of the air/vapor barrier and insulation within the wall assembly is critical, depending on the climate and the direction of vapor drive (moisture naturally moves from areas of high density to low density). We can analyze wall assemblies to determine the temperature at each point within the wall, and if there is risk of condensation forming within the wall (which can lead to mold growth, deteriorating structure, etc.).

      As for cladding – some materials may only be fit for certain climates and some may work everywhere. Cladding in many coastal areas must be able to handle hurricane force winds and impact loads from debris, while northern climates must be able to withstand freeze/thaw damage.

      • Mehrzad
        September 30, 2016 at 10:46 pm #

        Talking on the same note as Emily’s, the following article is interesting for hurricane-prone regions in the southern and eastern coasts of the US with high basic wind speeds. The upward movement of the rain water forced by the high wind may behave similar to the uplift suction effect of wind on roof components with respect to more common negligence of design and specification requirements. As with specific requirements such as ties usage to counteract the uplift force on the roof components, this upward water infiltration likely requires more strict specifications and construction consideration in the coastal zones since upon insufficiency of the waterproofing mechanisms, this water might be able to remain in the wall system after transporting through. The vapor generated due to heat in sunny times may further push the entrapped water, and water condensation in cold days may lead to cracking or spalling. Depending on the duration of the water being able to remain in the wall system, peeling paints and mold growth may occur.

        http://www.jlconline.com/how-to/exteriors/weathertight-exteriors_o

  13. Rebecca M
    September 25, 2016 at 3:56 pm #

    I found Emily’s waterproofing seminar to be incredibly insightful and helpful introduction to the systems in building science. One of the most interesting parts of the presentation was that, like all other building failures, failures in the wall water barrier are also unique. Despite there being, at a basic level, three types of wall construction, each project that shows signs of water leakage is a special case for how or why the leakage is happening.
    The three keys to success in wall water barriers also factor heavily into the service life of the system. As discussed in class, between materials, design, and workmanship, the component that fails most often is workmanship because of constructability issues, a lack of knowledge, or the pressure to finish the job on time.
    The selection of compatible materials, design of the system as a whole, and correct installation create questions for the investigator if the system shows signs of failure. In the original post for this discussion it is even brought up that some through wall systems are modified, reduced, or partially eliminated, likely because of the value engineering process. Because one of the most common types of building failures deals with water penetration and water barriers, it leads me to wonder why these systems are affected by value engineering? The application, installation and general success of these systems are crucial in the durability and life expectancy of a project.

    • Joe H
      October 2, 2016 at 5:01 pm #

      One of big patterns that seemed to repeat itself in some of the early, more general readings is that there is gap between designers, repairers, and installers that is very hard to bridge. Many designers will not check up on their buildings during installation or after completion, so they don’t know if their error led to the mistake. Then on the next design project, they do the same thing because they don’t realize what their previous error was.

      On the same note, repair engineers often do not do much new construction, so even though they understand what goes in to the mistakes, they are not in a position to make an adjustment and fix it on the next project.

      To me it seems that bridging this gap requires extra time and communivation, something that a lot of engineers are not able to spend with their demanding workload, so it just gets scathed over because it has for so long

  14. Mehrzad
    September 24, 2016 at 7:51 pm #

    As most non-performance occurrences of non-structural elements of a building and its envelope, water damage is most likely to initiate from mismatched bonds or connections between distinct materials/elements and not from within a certain element. This results from improper/inadequate detailing or installation of water transport mechanisms, and as Ms. Wychock categorized, the solution lies in improvement of Materials, Design, and Workmanship. The mismatch inadequacies could happen at masonry walls’ joints leading to efflorescence (salt crystallization due to evaporation of water that transports salts from mortar’s cement into the surface of the wall), as discussed in the lecture, or to cryptoflorescence (build-up of salt crystals below the surface causing wall spalling). Other critical points are at metal coping on top of the parapet and its transition to the top of the exterior wall cladding, cant strip (angled roofing along the meeting points of roof floor and wall/parapet) to direct water away from the wall, usage of various geometries of joints to more appropriately guide the water to outside of the envelope, insulation and a minimum required depth for the bottom of the foundation to be underneath the grade to prevent frost damage [not as a water penetration issues], vapor barrier under slab (on grade), waterproofing below grade plus a minimum elevation from top of wall foundation (above grade) to grade, various flashings and sealants at cavity and barrier walls (discussed in the lecture), etc.

    As discussed, with building enclosure comprising about 20% of new buildings’ costs, one of the most important aspects is diligence in utmost coordination between trades and consideration of sequencing requirements to minimize future non-structural or structural defects caused by water infiltration. This is achieved by the general contractor bringing together subcontractors involved in the construction of components of the building envelope and communicate design or material ambiguities with the design team and manufacturers.

  15. Ommar E
    September 23, 2016 at 8:16 pm #

    Stucco Woes—The Perfect Storm

    Eastern Pennsylvania is the stucco failure capital of the United States.

    One of the good examples for things go wrong with the building envelope or outer shell of the building so to speak is the Stucco failures that has increasingly becoming worrisome specifically in Eastern Pennsylvania. This is one of the issues that has widely been blamed on new materials. As the building envelope gets tighter, the chances for the building to breath as it used to do in older leakier (air leakage) buildings with traditional materials become smaller, causing all types of problems because of improper dry-out. The above mentioned article provides a good insight into this issue. Below it the link for the article.
    https://buildingscience.com/documents/insights/bsi-029-stucco-woes-the-perfect-storm#F01

  16. ErikS
    September 23, 2016 at 9:51 am #

    Thank you, Emily for coming to speak to us in class. It was a great overview of the issues building enclosure assessment experts deal with on a daily basis.
    To further expand upon the discussion and questions from class with regards to the extent of demolition/repair versus full replacement of a facade to repair the waterproofing/backup issues, it all depends on the project, as Emily stated.
    Recommendations from the professional must include comparison of the costs of all options for addressing the issues: Isolated repairs at specific locations such as those discussed in the case study (e.g., flashing lines, column lines, window perimeters); full-scale removal of the cladding and installation of new weather resistive barrier and flashings; over-cladding of the existing facade with metal panels, stucco, etc. Costs associated with targeted isolated repairs could range to nearly the cost of full-replacement when a good, qualified, contractor that specializes in masonry, water proofing, roofing, or other repairs and restoration is involved with the project because the skill and training required to selectively demolish brick, etc. and not have it crack, displace, or fall, as well as the replacement of the flashings, and relaying of the brick, is specialized and will often cost extra.
    These recommendations should also include an understanding of the impact on the building’s occupants with regards to length of time of construction, noise and vibration, and impacts to entrances and exits as well as a consideration of the overall aesthetics of the final repair. When the full facade is removed and replaced it may take less time than the targeted repairs and no matter how good the repair contractor may be the repairs will always stand out after construction; though better work product will blend into the existing better and quicker than lesser quality work.
    You may think that I am suggesting full-replacement is the better approach – not necessarily. It depends on the project size and scope, the client’s willingness to have repairs and to pay for the repairs, as well as may other considerations. Most jobs will entail detailed, systematic selective demolition to affect repairs as that is all that is required, but some, such as the example in class, may be better accomplished through the full-scale replacement of the facade. When there is no weather resistive barrier, no continuous through-wall flashing, no end dams, etc. it may be more beneficial to the owner to go the extra step. Again, this is all project specific.

    • Alec B
      September 27, 2016 at 7:35 pm #

      Erik,

      Your insight and shared experience is greatly appreciated as you always seem to provide a very unique perspective to every discussion topic. In your experience, after an investigation is performed on a failed facade, do structural engineers typically design repairs for the facade and/or design/coordinate the facade replacement? Or do the contractors tend to handle the repairs/replacement their own way without relying on repair drawings?

      • ErikS
        October 3, 2016 at 8:51 am #

        Alec, thank you, and sorry for the delay in response. This completely depends on the project, owner, repairs, etc. Firms such as WJE, SGH, RDH, etc. recommend having an architect/engineer investigate the failure, design the repair, and provide oversight during the construction, obviously to maintain a workload, but more importantly when the firm providing the repair design also conducted the investigation the details are generally more thought-out and integrated with the as-constructed conditions because they know first-hand what the issues and conditions are. Trying to look at photos or drawings alone can be difficult to completely comprehend the actual intricacies of the interface condition, structural deficiency, etc. Also, who better to assist and oversee the contractor during construction than the firm (and hopefully the actual A/E who performed the investigation and developed the repairs) who was involved from the beginning? The A/E firm will have the best understanding of what the intention of the repair is so when the contractor has a question a response or modification can be provided that best reflects the need of the project.

        There are often times contractors do conduct investigations, develop repair “documents”, and perform all the work in-house, and many contractors can do this effectively and with quality; however, as an owner, developer, even general contractor, it is often better time and money spent having an A/E involved throughout the project.

        This can be an issue, at least with regards to the construction phase services (CPS) (oversight) on government projects where the A/E who investigates often is not the A/E who develops the repair documents and then is almost never the firm who provides CPS.

  17. Alec B
    September 23, 2016 at 1:31 am #

    Emily’s talk gave a fantastic overview of building technology and the building envelope system. As understood in this course, one of the most common building performance failures involves the building envelope system as water penetration is likely to evolve into severe issues surrounding the long-term performance of the building. Throughout Emily’s talk, she made it very apparent that building envelope failures are dependent upon the “weakest link” of the system. The entire wall system may be waterproofed with an effective design, well-performing materials, and excellent workmanship; however, if one small area of the waterproofing membrane is not installed with the same level of workmanship as the rest of the membrane (ex: not properly overlapping the membranes near window openings/corners), water will penetrate and cause problems with the building’s performance.

    Through my additional research on related topics, I explored sloped glazing (or skylights). I found moisture protection of skylights to be particularly interesting because skylights are often exposed to larger volumes of rainwater and snow than typical windows/openings along the vertical faces of the building. I’d imagine the detailing of moisture protection of skylights to be extra particular and the installation most likely requires extra care and attention since skylights are more susceptible to water leakage. As referenced in the Whole Building Design Guide, the leakage and condensation must be collected and drained to the exterior by the means of a continuous drainage system composed of interconnected condensate gutters and sill flashing.

    One of the projects Emily discussed during her talk showcased a building envelope comprised of several different types of cladding materials (ex: metal panels, brick, storefront windows, CMU, etc.). Many buildings combine multiple types of cladding. I’d imagine that where two different types of cladding meet on a building, there are unique details that develop to ensure proper moisture protection. Does anyone have any experience with detailing the design of different cladding in relation to moisture protection?

  18. philr
    September 22, 2016 at 10:26 pm #

    Good presentation today as well as yesterday. An interesting theme kept coming up in both presentations. Most of the vapor / moisture barrier systems tend to work when installed exactly to manufacturers specifications by quality contractors. If the right people aren’t installing it exactly to spec, then chances are that problems are going to occur. Wonder if the manufacturers should build in a little installer “forgiveness” into their designs?

    • Joe H
      September 26, 2016 at 10:16 am #

      I had a lot of the same thoughts, but wasn’t sure how to word it. I think putting “forgiveness” into design is a really good phrase, as it would act a sort of safety factor. We have safety factors for all other aspects of design, so if there were a way to incorporate this into vapor barrier installation, this could alleviate many issues.

      The question is how this forgiveness can be built in. The most effective method would be to have a trained supervisor oversee the whole installation process. But this would be very inefficient and time-consuming if there is only one supervisor.

      A second option is changing installation requirements to have more material exposed than needed. So a longer flashing that goes past the facade, and maybe a wider vapor barrier or extra sealant for example. This then brings up constructability and aesthetics issues with the extra materials.

      A third option is better informing workers of the potential consequences of poor installation. But in an industry that is driven by speed and cost, this is a step not many companies would want to take.

      • MichaelB
        October 3, 2016 at 1:03 am #

        Joe,

        I agree their should be some way to ensure better construction methods for water proofing. Unfortunately I don’t think it would be as easy as a safety factor. It seems from Emily’s presentation that most water barrier problems stem from failures of installation.

        I think it should be up to the design engineers to convince the owner of the project that moisture barrier systems are important. If the owner recognizes this they can pester the contractor about making sure a moisture barrier system is installed correctly.

  19. Ommar E
    September 22, 2016 at 10:12 pm #

    Failure in buildings happens and could be expected in many ways. However, when it comes to water proofing and moisture treatments of the building enclosure, three key issues ought to be looked at carefully as shown in Ms. Wychock’s lecture. Material, design and workmanship.
    She confidently pointed out that the least expected failures would be in the material side of things. Thanks to rapid advancements in material sciences and high quality control manufacturing processes, especially in the last three decades. A good design also is a key to preventing future failures. But as new and innovative thing are being tried everyday mistakes happens. Sometimes things slips between the cracks and would not be caught till late in the process where the design has already been implemented. Still it is an area where many new technologies have now evolved to circumvent traditional design and construction pitfalls such as BIM and computer Aided design software.
    The area where failure is expected the most is workmanship. As, you could have the best materials and design out there but if you do not have the right crew to deliver on site then failure becomes inevitable. It worth mentioning and also as the lecturer has stated it is an area where the potential for improvement is the highest. A good training and close supervision could help in doing an excellent job, saving money and evading failure.

  20. Yamile R
    September 22, 2016 at 6:50 pm #

    Ms. Wychock’s lecture this morning was very interesting and full of details; I believe we all learned from her talk and the case studies.

    While listening to a few common situations they encounter in building enclosures, I was relating them to some of my past projects as an architect, in which I had to design and prepare building enclosure details. For instance, while I was designing a masonry commercial building, I had a brick wall from the outside penetrating the building, a window perpendicular to the face of the wall divided the exterior from interior every module. Back then, when I draw the detail of the masonry wall, I was not aware that it needed a water barrier to avoid the translation of water and moisture to the interior wall and inside the building. So conceptually, that wall is actually two walls attached together with a water barrier at the point where the interior becomes the exterior. As Ms Wychock said, we have to be able to draw an imaginary line, of water barrier, around the whole perimeter of the building.

  21. YusufA
    September 22, 2016 at 6:02 pm #

    I found todays lecture quite interesting and enlightening.

    Going back to previous experience with the failure of such barriers however, Scheduled maintenance needs to be arranged on the membranes in use for water proofing. This is because they all have a life span as specified by the manufacturers and a minor crack is all water needs to find its way into a building.

    Therefore workmanship supervision as well as periodic maintenance will go a long way in preventing major damage to both the visible and hidden building components which could later lead to a major failure.

    PS: The Salt reaction on Brick walls which she showed made me more observant to this and I actually found some in Engineering Unit B and a few other campus buildings.

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