Which of the following is not provided by unfaced insulation installed in wall cavities?

Which of the following is not provided by unfaced insulation installed in wall cavities?

• A. vapor barrier
• B. insulation value
• C. thermal resistance
• D. airtight seal

Answer: (A)

The reason unfaced insulation installed in wall cavities does not provide a vapor barrier is that unfaced insulation lacks a protective outer layer designed to block moisture from passing through. This absence of a facing material means that while the insulation is effective at slowing down the transfer of heat and providing thermal resistance, it does not actively prevent moisture accumulation within the wall cavity, which is essential in areas where humidity levels can be high. In contrast, insulation value and thermal resistance are inherent properties of the insulation material itself, reflecting its ability to resist heat flow, regardless of any facing. An airtight seal is also not a property of unfaced insulation, as achieving air tightness involves additional materials or techniques to seal gaps that insulation alone cannot provide.

The reason unfaced insulation installed in wall cavities does not provide a vapor barrier is that unfaced insulation lacks a protective outer layer designed to block moisture from passing through. This absence of a facing material means that while the insulation is effective at slowing down the transfer of heat and providing thermal resistance, it does not actively prevent moisture accumulation within the wall cavity, which is essential in areas where humidity levels can be high.

In contrast, insulation value and thermal resistance are inherent properties of the insulation material itself, reflecting its ability to resist heat flow, regardless of any facing. An airtight seal is also not a property of unfaced insulation, as achieving air tightness involves additional materials or techniques to seal gaps that insulation alone cannot provide.