What Happens When Condensation Sets in the Ceiling?

Causes of Condensation

• When comparing warm air versus cool air, warm air molecules can carry larger quantities of water or moisture than cool air. When warm air makes contact with cool air or a cool surface, warm air molecules drop in temperature. In effect, cooled air molecules can no longer hold their moisture content, which causes condensation or liquid to form on exposed surfaces. This process occurs when warm air travels into a cool room or anyplace where warm and cool air collide, such as on window surfaces. Enclosures with poor ventilation are particularly prone to condensation effects. Over time, ceiling surfaces can absorb water vapors in areas where air temperatures vary on a frequent basis.

Ceiling Exposures

• Condensation can form on ceiling surfaces and inside ceiling materials from temperature changes that take place above and below ceiling structures. Rooftops create a moisture-sealing barrier between the external environment and a building structure. As a result, warm air rising up through ceiling structures gets trapped just below the underside of a roof. During wintertime, warm air molecules colliding with cold roof under-siding causes condensation to form and eventually drip onto ceiling materials. Condensation can also form on ceiling surfaces that sit above rooms where warm and cool air collide or where warm room air collides with cool ceiling surfaces.

Mold Growth

• Ceiling surfaces affected by condensation may eventually cause paint or surface exteriors to disintegrate or change in texture. And while the effects of moisture and water can cause this to happen, mold growth may also contribute to changes in a ceiling’s appearance. Certain mold organisms, such as Penicillium and Rhizopus, can feed off of plaster, timber, and paper or fiber-based materials contained in a ceiling’s structure. Mold growth can result in cases where organisms have an ongoing supply of oxygen, organic-based residues and moisture. As different materials react to water and moisture in different ways, ceilings made from absorbent materials are most likely to allow condensation to set in and mold growths to occur.

Structural Deterioration

• Structural deterioration within ceiling materials and supportive structures, such as wooden beams, can develop over time as condensation effects eat away at affected surfaces. In addition to surface exposures, warm, moist air molecules can seep inside ceiling and wood materials. In cases where a material is cooler than incoming air molecules, moisture can form inside ceiling materials and wooden beams. When this happens, structures begin to deteriorate from the inside out and may go unnoticed until an actual break or collapse occurs. These conditions are also conducive to mold growth, which can further increase rates of deterioration.