A recent commercial inspection presented a unique case that demonstrates the application of building science. This case also demonstrates the value of a building inspection.
The subject property was a 3 year old prefabricated metal warehouse building that was vacant. The building walls and ceiling are fully insulated with plastic backed fiberglass insulation, which is typical for metal buildings. The white plastic backing is exposed inside the building.
I noticed some odd staining on the plastic insulation backing. Rusty stains were running down the white plastic, but I was certain the roof was not the source.
Stains on plastic insulation backing
I found droplets of water at the base of a couple of the steel columns, along with water stains running down the columns.
The building steel was prematurely rusted, indicating moisture problem. Some of the steel had a sheen of water visible on its surface.
After some head-scratching, I came to the conclusion that the source of the water was condensation. The building was vacant and had no ventilation. The excellent insulation and plastic vapor retarder create conditions similar to those inside a plastic bag. As humid air is cooled, it reaches the dew point, causing the water vapor in the air to condense. The steel is an excellent conductor, and therefore loses its heat more rapidly than other materials, becoming cooler sooner. That’s why we’re seeing the free water forming on the steel first.
The client plans to store collectible automobiles in the building. Obviously, this environment is not suitable for storage of anything metal, especially old expensive metal objects. My recommendation was to consult an HVAC contractor regarding options for dehumidifying and/or air conditioning the space.
This case demonstrates the value of hiring an experienced inspector for any purchase. Because the building was only a couple of years old, the client had considered not having it inspected at all! That could have been a very costly mistake.
Mark Cramer
Mark Cramer Inspection Services, Inc.
492 20th Ave.
Indian Rocks Beach, FL 33785
727-595-4211
http://www.BestTampaInspector.com
Advice for consumers on choosing a home inspector in Tampa, St. Petersburg or Cleawater
Posted via email from Clearwater St. Petersburg Tampa Home Inspection News
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