Which material is used to prevent moisture passage into building walls and floors?

A vapor barrier is a material specifically designed to prevent moisture from passing through building walls and floors. This is crucial in construction and building maintenance, as moisture intrusion can lead to various issues, including mold growth, structural damage, and compromised indoor air quality.

Vapor barriers are typically made from materials like polyethylene plastic, which are impermeable to moisture. They are installed in areas where moisture might enter, such as beneath concrete slabs or on exterior walls, to create a barrier against water vapor.

While insulation can help reduce heat transfer and improve energy efficiency, it does not necessarily prevent moisture movement. Sealants are effective for filling gaps and cracks to stop air and water leaks at specific junctions but do not provide the comprehensive moisture protection offered by a vapor barrier. Waterproofing refers to measures taken to make a structure water-resistant, but this can involve different techniques and materials that may not specifically act as a barrier to vapor. Thus, the vapor barrier is the best choice for the specific function of blocking moisture passage into walls and floors.