Peeling Back A Mystery

Recently, we were asked to investigate a building where mold was growing in the walls. During the investigation, we came across a product that we had not encountered before. It was a sheetrock panel with a shiny aluminum backing.

These panels are made by laminating special kraft-backed aluminum foil to the back surface of regular drywall panels. After reviewing the product literature, the panels offer some desirable qualities as they are intended to create a vapor retarder that helps prevent interior moisture from entering via exterior walls, it helps maintain comfortable room humidity all year-round, and creates a comfortable temperature during the appropriate seasons.

After reviewing the product limitations, we found that this drywall was not ideal for our situation. This was primarily because the interior walls were decorated with vinyl wallpaper, which created a double vapor barrier on the interior wall.  This condition trapped moisture and created a place for mold to grow.  Unfortunately, because the foil backing was not visible, no one knew that a problem was created by adding the wallpaper. Sometimes even simple cosmetic changes can lead to unexpected consequences.