Drywalls are often strengthened with vapor barriers to make them more durable. However, the presence of vapor barriers among drywalls isn't a standard practice. Many of the contemporary residential spaces are also built without them. Further, vapor barriers aren’t recommended for all types of drywalls. Homeowners should be equipped with the basics of vapor barriers and to recognize the need to install them.
Drywall & Vapor Barrier Basics
Drywall refers to one of most conventional building materials wherein gypsum plaster is impacted within layers of fiberglass or paper matting. Drywalls are commonly used in a home’s inner walls. Drywalls exude a smoother, more finished appearance than other walls. However, just like any other wall in the house, a drywall is susceptible to damage induced by issues like moisture seepage.
A vapor barrier is essentially refers to any building material that is used for creating a resistance against the passage of water vapor and moisture within the drywalls. Vapor barriers are often installed in the form of plastic sheets or foil sheet. Contemporary landscapers also use vapor barrier paints and coatings at the time of drywall repairs. Vapor barriers are also referred to as vapor retarders.
Homeowners should consider vapor barriers during drywall installation when there is:
Indication of Planned Constant Moisture
If homeowners plan to install showers, baths or sauna in their homes, they will need to install vapor barriers in those rooms' interior walls. Bathrooms should at least have vapor barriers in the walls that make up the shower or bath unit, if not vapor barriers throughout the home. Even when walls are covered in tiles, grout, and sealant, moisture seepage can still occur over time. Saunas won't have running water directly hitting their walls, but they will have high humidity for extended periods of time, which will eventually affect the walls.
Indication of Moisture-induced Damage
If any of the interior walls have a history of moisture seepage, using vapor barriers is seriously recommended. If any of the walls are prone to getting discolored rather quickly or developing a disturbed texture even after periodic repairs, moisture-related problems are indicated. Typical signs of moisture seepage within drywall includes wrinkling of the wallpaper or bubble like spots along the painted surface.
If the homeowner isn't familiar with the nature of walls in a new residential space, the same can be inquired about from the neighbors. This is because many times residential walls become susceptible to moisture seepage due to typical weather and soil conditions in a region. This includes sustained humidity or the presence of excessively-wet garden soil.
Indication of Vapor-induced Damage: Wall Damage without Traceable Source
Most homeowners believe that a plumbing issue or moisture seepage from the basement is damaging their drywalls. However, drywalls are susceptible to a different form of damage, i.e. induced by water vapor and not direct seepage.
Moisture seeps within a house through two mechanisms—direct diffusion that is easily traceable in the form of wet spots on the walls and through air in the form of water vapor. The vapor isn't visible and it condenses against the surface of the drywalls due to temperature differences, causing untraceable moisture-seepage.
This kind of problem is easily eradicated by inducing a vapor barrier. The alternative solution include better ventilation, use of humidifiers and upgrading the insulation properties of the house—each of these is expensive than installing a vapor barrier.
Indication of Mold/Mildew Problems
Drywalls have a gypsum-heavy core that makes them very durable. However, the paper-based/fabricated wrapping creates the issue of molding. This is because these layers contain a high amount of cellulose. This material is prone to absorbing moisture with ease. Further, moist cellulose is extremely vulnerable to developing mildew and mold. Either of these is a serious health hazard and can induce severe respiratory problems among the home’s occupants. Mold spots usually surface as small, blackened dots on the wall.