A vapour barrier is a construction material used to control the flow of water vapour in building structures.

The primary purpose of a vapour barrier is to prevent the penetration of water vapour from inside the building into insulated spaces, which can lead to moisture and mould problems.

Vapour barriers are commonly used in walls, roofs, floors, and ceilings to maintain the proper moisture balance in a building.

They can be used with thermal insulation to provide effective protection against heat loss.

Vapour barriers can be made from various materials such as polyethylene film, aluminium foil, or vapour retarder membrane.

Installing a vapour barrier requires careful attention to detail and ensuring the seals are tight to prevent vapour leakage.

It's important to consider local building codes and recommendations for the proper use of vapour barriers to ensure compliance with standards and regulations.

Proper installation of a vapour barrier can contribute to increased energy efficiency in a building and prevent moisture and mould issues.