Q: I recently read an article in a magazine that described a method of raising the heat of all the materials within a space to a critically high level in order to kill mold. The method was presented as new technology and I would like to find out more about it in detail. Do you have any ideas or references I might use?

Part of the reason for asking the above question is driven by a moisture condition in one of our oldest buildings on campus. A contractor working on restoring the eaves and soffit, allowed rain to get inside the full brick walls on one side of the building. We are trying to determine the best way to dry it out and prevent mold from developing or growing.

A: Exterior walls that have had moisture intrusion from one source or another tend to be problematic. The first item to address is to make sure that the source of the moisture intrusion has been stopped or fixed. This must be done to ensure no further damage can occur as continual moisture versus a one time moisture event makes a big difference for the likelihood of mold growth/damage to occur. Once the source of the moisture has been eliminated, the next step is to try to determine where the moisture may have migrated to from the roof down and consequently where there may be moisture present in the wall. Determining how the exterior wall of the building is constructed will help identify where the water may have most likely migrated to. By knowing the construction the locations to look, along the exterior wall water path, for moisture/mold damage may be evident.

Representative locations in the wall along this possible path should be reviewed either by testing with a moisture meter or accessing areas of the wall (cutting an access hole) for a visual assessment. If a moisture meter is used, the proper setting must be used to correspond to this application (I.e. wall type such as gypsum board, plaster) and the manufacturer's directions and guidelines for use must be closely followed. If moisture appears to be present with the use of the moisture meter, additional access may also be required to perform a visual assessment to clearly determine the extent of the damage. The visual assessment observations are the best method to accurately assess the actual conditions related to both moisture and mold.

Once the possible water migration path is determined, along with verification of the presence of moisture/mold damage, the next step would be remediation. If there is no visual mold damage present, then drying out the affected moisture damaged areas is needed. Drying out the wall cavity can be difficult especially if there is insulation in place on the exterior wall. If there is wall insulation, the only clear way to ensure that the moisture is dried out is to access the wall in these areas and remove and replace the water damaged materials. If this is not feasible, then cutting access holes at the top and bottom of the wall at the wall stud spaces will help allow an air path for the wall to dry out a little. If this access holes method is used, then periodic visual observations would be necessary to ensure that mold growth does not occur. If there is no wall insulation then providing access holes are each wall stud spacing will generally allow the wall to dry out. The key is to allow an air path to occur that will allow the drying process to occur. Should there be mold damaged observed then the mold damaged materials need to be removed and replaced using the proper mold removal techniques.

Rick Anderson is district manager for EFI Global's Houston office and can be reached at rick_anderson@efiglobal.com or 832-518-5145.

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