Addressing Moisture Intrusion In Buildings

Examine facilities inside and out when investigating building envelope intrusions.

By Michael Smalley
From the February 2020 Issue

Moisture control is essential to any building. Not only can the presence of moisture affect the structure and integrity of a building, it can also lead to serious health issues for occupants. Typically, building owners and facilities maintenance personnel go under the microscope when these issues arise as many moisture problems can be traced to errors in design, construction, and maintenance.

Building Enclosures Leaks

moisture intrusion
(Photo: HotHibiscus)

Building envelope leaks typically occur at transitions between enclosure systems. All the products on the market—glass/window systems, weather resistive barriers, and architectural panels, among others—are tested to see how long they will be effective. The systems that are installed on a building are expected to perform for the duration of the warranty. Moisture issues typically occur when one system transitions into another. These can lead to gaps in the protection of the building. Unfortunately, during construction the responsibility for making sure these transitions are held to the same level of expectation can be a void in the matrix.

During construction, understanding the building’s function and use is important. One must understand what the building is being used for, what the occupancy total is, and what the energy levels are. This knowledge can determine what systems should be used on the building. For example, there are minimum coding requirements for glazing and architectural panels. If the builders deviate from those requirements, it may cause more issues than many realize.

Compatibility is also important during construction. It is important to make sure all installed systems are compatible with each other. If the products are not meant to coexist, issues will likely follow. If they are not compatible, the products may not even last until the warranty’s expiration date. Compatible systems are even more critical at the transition areas. For example, the sealant needs to be compatible with the weather barrier, and the weather barrier needs to be compatible with the roof.

Signs Of Intrusion

Within finished interior spaces, the most familiar sign of moisture intrusion is mold. While the awareness is high, unfortunately, mold is probably the worst thing that can happen. If there are signs of mold, there are issues somewhere that have likely been going on for some time. Many people do not know there is a problem until mold appears. Mold will affect the structure of the building. Furthermore, building function and performance can be ruined.

moisture intrusion
Building envelope leaks typically occur at transitions between enclosure systems. (Photo: roman023)

Mold growth can also affect the health of everyone inside a building. Molds can cause coughing, nasal stuffiness, throat irritation, wheezing, or skin irritation. People with mold allergies can have even more severe reactions. Furthermore, health issues caused by mold can lead to lawsuits. In 2016, a music teacher from New Jersey was awarded $1.8 million in a lawsuit against her school district. The teacher claimed that dripping water in her classroom led to mold growth. She was later diagnosed with adult onset asthma and other pulmonary conditions attributed to mold exposure.

Another sign of moisture intrusion is condensation in or on the windows. This indicates there is some sort of air or vapor coming in. The air or vapor could eventually turn into water, making it necessary for the leak to be found.

Any pooling of water is also a sign. However, that is rarer and not always easy to find. It does not always collect in an area where it can be seen. Many people do not think to look for water. So, unless specifically being inspected for, it is not always seen.

When Moisture Intrusion Occurs

If an intrusion occurs, the first thing that should be done is to identify the entry point, which is not always easy. Just because it is seen there, it does not mean that’s where the moisture is coming in. It could be seen at one corner of the building, but actually be coming in at another area. Plus, if there is one issue, there might be other problems that have not been discovered. For example, if there is a leak at a certain curtain wall condition, that issue could exist at all or similar conditions. It is best to make sure that issue is isolated and not a systemic problem. All curtain walls need to be inspected in that case.

One can work with a consultant or testing agency to investigate to find out where it is coming from. This might entail some obtrusive work to the building, such as removing some bricks, panels, or some caulk, but it is necessary to get to the root of the issue. Someone qualified with a reputable work history can identify where the issue is.

Next, it is critical to work with the agency or consultant to put together a plan for mitigation. A good strategy is to talk to the manufacturers of the building supplies—such as the air barriers, windows, or sealants—and have their local representatives come in and provide suggestions. Sometimes there are specific changes that need to be made to fix the issues, instead of trying to make repairs with a broad brush. There is always a specific area where the repairs need to be made.

moisture intrusion
Moisture intrusion can present itself close to the source, or it can travel further into the building envelope. (Photo: Cunaplus_M.Faba)

It is important to know who to call. A good tip is to reach out to someone who knows the building and the systems that are in place. Another is to review the manuals that the manufacturers provided during installation and do the proper research to be able to engage with the manufacturers’ representatives.

After the mitigation plan, it is important to retest the areas that needed to be fixed under pressure. This can be done by many field tests, including AAMA 501.2 Field Water Infiltration or ASTM E1105 Static Water Infiltration. It is always a mistake to assume that the repairs immediately fixed all issues.

While it may be hard to obtain, it is helpful to get warranties for the repairs. If the repairperson can provide a workmanship guarantee, it can be beneficial. While this does not always occur, it should be a goal.

Protect The Building Envelope

In order to mitigate potential moisture intrusion, regular inspections are critical. This does not just involve looking inside. It is beneficial to test annually inside and outside of the building. Adding proactive testing into the budget can help prevent larger expenses down the line, including moving tenants or shutting down the building. Otherwise, by the time a leak is found, it could be too late.

With the damage that moisture can do to the integrity of buildings as well as the health of its occupants, it is crucial to make sure the proper products have been installed on the building. If or when issues do occur, a good practice is to bring in qualified individuals, making sure the repairs are done correctly. Proper due diligence can protect the building and occupants, not to mention the bottom line.

Smalley is the director of business development for IWR North America and has more than a decade of industry experience. IWR North America, headquartered in St. Louis, MO, is one of the longest standing specialty contractors in the U.S. that focuses on being a true building enclosure partner. IWR is a subsidiary of MHS Legacy Group, a diversified national holding corporation also based in St. Louis with roots dating back to 1895.

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