PVC boards, including integral foam PVC, foamed PVC panels, expandable PVC, Celtec PVC foam board, and Celtec board, vary in their moisture permeability, which is a crucial factor in many applications.

PVC, or polyvinyl chloride, has a natural resistance to water absorption due to its chemical structure. The molecular chains of PVC are tightly packed, celtec board，making it difficult for water molecules to penetrate. This basic property is the foundation for the low moisture permeability seen in PVC boards.

Integral foam PVC, celtec board，with its unique cellular structure, expandable pvc shows interesting moisture - related behavior. The closed - cell nature of integral foam PVC restricts water movement. Water cannot easily enter the cells, and even if it reaches the surface, celtec pvc foam board it has a hard time finding pathways to penetrate deeper. This results in a very low moisture permeability, making it suitable for applications where water resistance is key, celtec pvc foam board，such as in some outdoor construction projects.

Foamed PVC panels, similar to integral foam PVC,expandable pvc， also have a foam - based structure. The foaming process creates a network of cells. In well - made foamed PVC panels, these cells are mostly closed. Water has to navigate through the small gaps between cells, which significantly slows down its penetration. This gives foamed PVC panels good resistance to moisture, protecting underlying structures from water damage.

Expandable PVC, during its expansion process, forms a structure that can also impede water flow. The expanded matrix has a complex geometry that water molecules struggle to traverse. This property makes expandable PVC useful in applications where water exposure is a concern, like in certain waterproofing layers.

Celtec PVC foam board, a popular type of PVC foam board, has a moisture - resistant nature. Its foam structure, combined with the inherent properties of PVC, results in low moisture permeability. This allows it to be used in environments where moisture is present, such as in humid indoor spaces or in some outdoor applications where it may encounter rain.

Celtec board, which likely refers to a product related to Celtec, also benefits from the general moisture - resistant characteristics of PVC. Whether it has a foam structure or a different form, the PVC material in it provides a barrier against water penetration, ensuring its dimensional stability and durability in the face of moisture.