Building Envelope & HVAC Interaction
in Warm, Humid Zones

By George H. DuBose, CGC; Richard Scott, AIA, NCARB, LEED AP; and Donald B. Snell, P.E., Cert. Mech. Contractor, CIEC

building failures
This high-rise resort in Central Florida underwent a $9.5M remediation only to have the problem come back the first summer after it was complete.

Certain faulty beliefs surrounding building performance in warm, humid zones continue to persist in the design and construction industry – and the interaction between building envelopes and HVAC systems is no exception.

Unfortunately, the fact that many architects and engineers rely on such myths as gospel truth during building design has inevitably led to building failures that are often catastrophic in scope.

Below is one prevalent myth our experts at Liberty Building Forensics Group (LBFG) have encountered through their extensive work resolving mold and moisture problems in hotels and resorts. The myth is followed by an explanation of why it is false, as well as a first-hand case study supporting this position.

Myth: A building envelope can perform effectively on its own without any help from the HVAC system. Continue Reading No Building Envelope is HVAC Failure-Proof

Myth―An unproven or false collective belief

By J. David Odom and Richard Scott-AIA, NCARB, LEED AP of Liberty Building Forensics Group and Norm Nelson of CH2M

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If PTAC units were a federally regulated drug, then each equipment sale would include a list of side effects and cautionary notes. Unfortunately, the opposite is true—each PTAC buyer is provided with a list of unproven expectations and myths. It is these unproven PTAC performance myths, enduring for decades, which have contributed to an outsized number of moisture and mold problems.

Over the past 30 years, our building experts have investigated hundreds of hotel moisture problems (involving over 100,000 guest rooms) and in the process, have seen three repetitive problems that appear to be ignored by the hospitality industry:

  1. PTAC units cannot ventilate interior spaces.
  2. PTAC units cannot pressurize hotel guest rooms.
  3. PTAC units are often ineffective in dehumidifying hotel guest rooms, especially when outside conditions are hot and humid.

Even though PTAC units cannot provide these features, the myths are that hotel industry, including owners, operators, developers, contractors, and designers, believe that they can. Continue Reading The 3 Myths of PTAC Units

moisture problems

Suppose there was a tool that could predict, before a single penny was spent on construction, the likelihood of whether your building would fail. Not only that, but this tool could also provide you with enough information to make significant design changes that would dramatically decrease any risk factors. Would you be interested? Of course you would.

At the risk of oversimplifying a complex process that contains multiple variables, we believe we have created such a tool. The following moisture prediction charts have been adapted from a mold and moisture manual Liberty Building Forensics Group developed for Disney Corporation in the early 1990s. Over the past two decades, they have been beta-tested on literally thousands of hotels, and have proven time and time again to be as true today as they were 20 years ago.

Although the charts were created with hotel guest rooms and wall cavities in mind, the general principles demonstrated would hold true for most buildings. Hotels just happen to be the simplest commercial building structure, so they were the easiest to beta test. Continue Reading The Incredible Predictability of Moisture Problems

When Your Student Housing Property has Water Intrusion and Mold,

the Last Man Standing Could Be the Loser!

 

An increasing number of legacy buildings, including aging student housing complexes, are experiencing water intrusion and mold-related damage that can be traced back to fundamental design and construction defects. The buildings have experienced water intrusion that, in many cases, results in hidden damage to the structure.

While there may be some signs of the water intrusion inside the student apartments, the damage may not be obvious to the management firm. Unfortunately, by the time the damage is found, the statute of limitations for original designers and contractors is long gone. As a result, the buck often stops with the liability insurance of the current student housing management firm. This firm will be considered the last man standing.

Regardless of where the root problem originated, management firms are being held responsible for these defects if they haven’t taken steps to protect themselves. Managers of older student housing complexes who find themselves in this precarious position should understand the ways to manage their risks.

 

Continue Reading Campus Community Management Firms, Beware!

Avoid Catastrophic Mold and Moisture Problems in Hot, Humid Climates Due to Air Barrier Standard Confusion

 

By George DuBose, CGC; Richard Scott, AIA, NCARB, LEED AP; and Donald B. Snell, PC CIEC

 

Imagine the following scenario: you just designed your newest project to meet the most current whole building air leakage standards, and your mechanical engineer subconsultant has designed an HVAC system that includes one of the latest energy recovery strategies. Both factors are intended to meet high energy efficiency goals, making you proud that your firm is doing its part (amongst other things) to minimize your impact on the climate change problem.

Continue Reading Till Death Do Us Part: Preventing a Facade and HVAC Divorce When It Comes to Air Barrier Performance

As the building and construction industry continues to come out of the hibernation that has been the norm since 2009, it unfortunately appears that it’s déjà vu all over again when it comes to water-related building failures. As new buildings are being constructed, the same design and construction deficiencies of the past are being repeated, leading to (often catastrophic) mold and moisture problems.

 

It may seem somewhat unbelievable that the industry still finds itself making these same basic mistakes time after time. After all, preventative solutions to these issues have been understood and well-published for many years.

 

Continue Reading Design and Construction Amnesia: We Have Lost our Minds and it is Causing Catastrophic Mold and Moisture Building Failures

photo credit: Scott Ehardt


 

You are a defendant in a lawsuit. The crime? A moldy, moisture-damaged building. What you don’t want to have to say during deposition while under oath, “Lordy, I hope there is tape!”

 

Continue Reading Lordy, I KNOW there’s tape!

The emergence of #modular construction as an option for new construction is becoming mainstream. The reasons have been reported on well. However, what has not been reported is that the modular construction industry has had mold and moisture problems, especially, when used in a warm and humid climate like the Southeast US. Both wood frame and steel frame modular construction have experienced problems with crawl space, marriage wall, and ceiling to floor cavity, condensation problems that have not only resulted in deterioration of the wood, corrosion of metal floor pans, deteriorate wallboard and mold.

 

The greatest risk of modular construction failures has been seen to be when this type of construction and delivery is used for hotels, student housing, senior living, soldier housing, type facilities. In general, facilities that are domicidal or multi family in nature. This is because these types of facilities have inherent similarities in a living unit that requires both an individual cooling/heating unit, bathroom exhaust, and some sort of central HVAC make up air system. In addition, there are many more modular “boxes” in these kinds of buildings increasing the number of marriage wall interior cavities and ceiling to floor cavities that otherwise might not be required in other types of modular construction. The nature of modular construction makes it difficult to repair once it is found to be damaged. Sometimes, the damage can be such that the modular building has to be deconstructed to remove damaged materials and then re-designed and re-constructed using conventional methods. This essentially makes the modular construction advantages dissolve away as the building gets converted to a traditional “stick” building.

Continue Reading Deja Vu All Over Again: Risks for Moisture and Mold Problems in Modular Construction

 

Just months after completing refurbishment on a 300+ room resort, the owner of a luxury coastal vacation resort began to wonder if he had entered into the Twilight Zone when mold and moisture problems suddenly emerged in numerous guestrooms. He was perplexed that this problem was cropping up now despite the fact that he had owned and operated similar properties for many years. Never in all that time had he ever experienced moisture-related issues.

 

Why was the problem occurring at this point? What was different?

Continue Reading Has Coastal Zone Hotel Construction Become the Twilight Zone for Mold & Moisture Control?

 

What Did You Miss? What Did Building Owners, Developers, and Contractors Miss?

Richard Scott, AIA – Vice-president, Senior Forensic Architect

Over 15,000 architects attended the recent AIA 2017 National Conference on Architecture (A’17) in Orlando, Florida. What did they learn that you missed?  As a speaker and attendee, the following are the top three things I learned at this invigorating Conference:

1. Building forensic sessions were well attended, and still scare architects. And building forensics should still be scaring owners, developers, and contractors. There were over a dozen sessions on building envelope technology, disaster avoidance, and commissioning, some presented by forensic experts. Even the 7 AM forensic sessions, such as my Liberty Building Forensics Group (LBFG) presentation on air barriers, had over 100 attendees even though it was concurrent with 19 other sessions. No one likes a building failure unless of course, it is someone else’s failure.  So advice on prevention, based on failure case studies, drew many interested parties, questions, and concerns. Those who did not attend may want to at least obtain the handouts from forensic sessions.

 

LBFG’s session not only presented the complexity and difficulty of specifying and constructing air barriers but also the checkered and uncoordinated landscape of code and industry standard requirements (the session handout is available on the AIA A’17 app as well as LBFG’s website, www.buildingforensicsgroup.com). LBFG’s business is investigating and litigating building envelope and HVAC failures. The combination of failed envelope air barriers and failed HVAC leads to exponential damages to building facades, structures, finishes, and contents.

 

Continue Reading The Top 3 Things I Learned At This Year’s AIA National Conference on Architecture