A thin layer of impermeable material, typically polythene sheeting, included in building construction to prevent moisture from damaging the fabric of the building.
防潮层，隔汽层
Example sentencesExamples
Installing subfloor insulation with the vapor barrier on the downward side can cause moisture condensation on the framing and subfloor.
This vapor barrier will prevent evaporation of ground moisture, thereby reducing the likelihood of condensation.
The masonry walls are lined with heavy concrete blocks and separated from the rest of the building by a vapour barrier, so minimizing changes in temperature and humidity.
It is the purpose of the vapor barrier to prevent that movement or penetration of moisture from one area to another.
The necessity of constructing a vapor barrier for humidity control around the building - all museums require them - complicates things further.