Can you cover fiberglass insulation with plastic?

Before diving into the feasibility of covering fiberglass insulation with plastic, it is important to understand the reasons behind such a decision. Here are a few common scenarios where people consider this option:

1. Moisture control: Fiberglass insulation is susceptible to moisture damage. Excessive moisture can reduce its insulating properties and lead to mold and mildew growth. Covering fiberglass insulation with plastic can act as a vapor barrier, preventing moisture from seeping into the insulation material.
2. Preventing disturbance: Fiberglass insulation is typically installed between wall studs or in the attic. Since it is not a solid material, it can easily be disturbed by wind, animals, or human activities. Enclosing it in plastic can provide an additional layer of protection, keeping it intact and maintaining its insulative benefits.
3. Dust control: Fiberglass insulation can produce small airborne particles if disturbed. These particles can cause respiratory issues when inhaled by individuals. By covering fiberglass insulation with plastic, the release of these particles can be minimized, contributing to a healthier indoor environment.

Feasibility of covering fiberglass insulation with plastic

Now let’s delve into whether it is feasible to cover fiberglass insulation with plastic:

1. Vapor barrier: Plastic can indeed act as a vapor barrier when properly installed. However, it is crucial to ensure that the plastic is impermeable to moisture. Polyethylene sheeting with a thickness of 6 mil or higher is commonly used for vapor barriers. These sheets should be sealed tightly to prevent any air or moisture intrusion.
2. Dangers of encapsulation: While covering fiberglass insulation with plastic may seem like a logical solution, it is important to note that encapsulating fiberglass insulation completely can have drawbacks. Fiberglass insulation requires airflow to function optimally. By completely covering it, you risk trapping moisture, reducing its insulative capabilities, and potentially leading to mold growth.
3. Proper installation: If you decide to proceed with covering fiberglass insulation with plastic, proper installation is crucial. Ensure that the plastic does not compress the insulation or hinder air circulation. Avoid using tape or adhesives directly on the insulation, as they can degrade over time and release harmful chemicals into the air.
4. Fire safety: When covering fiberglass insulation with plastic, it is vital to consider fire safety measures. Plastic is highly flammable and can contribute to the spread of fire. Make sure to consult local building codes and fire safety regulations to determine the required fire-resistant rating for the plastic used.

Covering fiberglass insulation with plastic can be a viable option for moisture control, preventing disturbance, and dust control. It can act as a vapor barrier and help protect the insulation from moisture damage. However, it is essential to consider the potential drawbacks of encapsulating fiberglass insulation completely, such as reducing its insulative capabilities and promoting mold growth. If you decide to cover fiberglass insulation with plastic, follow proper installation techniques, ensure adequate ventilation, and consider fire safety precautions. Consulting with a professional insulation contractor or building expert is always recommended to ensure you make an informed decision tailored to your specific needs.