What is the primary use of vapour barrier mastic?

The primary use of vapour barrier mastic is to provide a moisture proof seal. This type of mastic is specifically designed to prevent moisture from passing through various building materials, thereby protecting structures from water damage and mold growth. It is applied in vulnerable areas where water infiltration could occur, such as seams or joints in vapour barriers, to create a continuous, impermeable layer.

This sealing capability is critical in both residential and commercial construction, as it helps maintain the integrity of the building and the health of its occupants by ensuring that moisture does not penetrate the living spaces. The other listed functions, such as improving thermal resistance and enhancing soundproofing, are not the primary roles of vapour barrier mastic; instead, they pertain more to different types of insulation solutions or wall treatments. Additionally, while aesthetics are important in construction, vapour barrier mastic is not typically used as a decorative finish. Its main focus is on moisture control and protection.