In air barrier contexts, what does 'compressibility' refer to?

In the context of air barriers, 'compressibility' specifically refers to the potential of a material to change thickness under pressure. This characteristic is crucial because it influences how well an air barrier can maintain its integrity when subjected to various loads and environmental conditions.

When a material is compressible, it can deform and adjust in response to external forces, which may affect the performance of the air barrier system. For instance, if an air barrier is compressed too much, its air-tightness might be compromised, leading to increased air leakage and reduced energy efficiency in the building. Understanding the compressibility of different materials helps in selecting the right components for effective air barrier applications to ensure they perform well regardless of physical forces acting upon them.

The other options do not accurately define compressibility in this context. The ability of a material to absorb water pertains to its hydrophilicity or permeability, not compressibility. Flexibility of the air barrier material relates to its ability to bend or stretch without breaking, while effectiveness in cold weather deals more with thermal performance rather than how the material responds to pressure.