It is generally not recommended to put plastic over insulation in an attic. While plastic sheeting might seem like a good idea to prevent moisture from entering your home, it can actually cause more harm than good in most cases. Here's why:
Moisture Trapping: Plastic sheets can trap moisture that may already be present in the attic. Moisture can come from various sources like humidity, roof leaks, or condensation. When moisture is trapped, it can lead to mold and mildew growth, which can be harmful to your health and can also deteriorate the insulation and the structure of your attic over time.
Lack of Ventilation: Attics require proper ventilation to allow any moisture that enters the space to escape. When you cover the insulation with plastic, it prevents the natural flow of air, leading to stagnant and humid conditions in the attic.
Inadequate Air Sealing: If you place plastic directly over the insulation, it may not create an effective air barrier. Air leaks can still occur, reducing the overall efficiency of your insulation.
Risk of Fire: Placing plastic near electrical fixtures or wiring can be a fire hazard. If any electrical components in the attic malfunction or overheat, the plastic can melt and increase the risk of a fire.
Instead of using plastic, it's essential to focus on proper attic insulation and ventilation:
Insulation: Ensure that your attic has the appropriate type and amount of insulation for your climate. Consult with an insulation professional to determine the best insulation material and R-value (a measure of insulation effectiveness) for your home.
Air Sealing: Seal any gaps or cracks in the attic to prevent air leaks. This will enhance the effectiveness of your insulation and prevent the entry of unwanted moisture.
Ventilation: Ensure your attic has proper ventilation to allow air circulation and the release of moisture. Ridge vents, soffit vents, and gable vents are common types of attic ventilation.
Vapor Barrier: If your climate requires a vapor barrier to control moisture, it should be installed correctly on the warm side of the insulation (usually facing the living space), not directly on top of the insulation.
Before making any changes to your attic, it's best to consult with a professional insulation contractor or an energy auditor who can assess your specific situation and recommend the most suitable insulation and ventilation strategy for your home.