In general, how do open-cell foams compare to closed-cell foams regarding water movement through walls?

Open-cell foams are designed with a structure that has many tiny cells, which are not completely closed off. This allows for some flexibility in the material and enables water vapor to move more freely through the foam. Consequently, open-cell foams are generally more permeable to water vapor, making them effective for applications where moisture management is important, such as in interior wall insulation where some level of moisture exchange is desired.

On the other hand, closed-cell foams have a denser structure with cells that are completely sealed. This characteristic makes closed-cell foams much less permeable to moisture. As a result, they act as a barrier to water movement, providing better insulation and moisture resistance.

Understanding the difference in how these foams interact with water is crucial for selecting the right material for insulation in various building conditions and climates. Open-cell foams, therefore, facilitate more water movement compared to closed-cell foams, which is essential information for anyone involved in building science and insulation practices.