Which insulation type offers higher resistance to moisture penetration?

Foam board insulation is well-known for its higher resistance to moisture penetration compared to other insulation types. This characteristic is primarily due to its closed-cell structure, which effectively limits air movement and moisture infiltration. As a result, foam board insulation not only acts as an effective thermal barrier, but it also helps prevent moisture-related issues such as mold and mildew growth, which can compromise the integrity of both the insulation and the structure itself.

In contrast, fiberglass insulation is less resistant to moisture because, while it does not absorb water, its batting can allow moisture to travel through it. Cellulose insulation, made from recycled paper products, is also susceptible to moisture absorption, which can lead to reduced effectiveness and potential mold issues. Mineral wool insulation, despite having some hydrophobic properties, does not offer the same level of moisture resistance as foam board insulation. Therefore, foam board insulation is the superior choice when moisture resistance is a critical concern.