Vapour sealing joints are very important when installing plasterboard, especially to prevent heat leakage. Under the subfloor grid, which is either wooden or made of CW profiles, it is necessary to use double-sided foam backing tapes. Any penetrations damaged by screws will provide protection against possible water vapour diffusion at these very points. The individual joints of the vapour barrier must be joined with suitable tapes. We do not recommend aluminium tapes as they usually have a very small layer of adhesive. Green or yellow strong adhesive tapes are suitable. It is on these details that you should not skimp.
Example of incorrect implementation
An example of incorrect implementation is documented in the soffit of a building with a gable roof. The vapour barrier was only adhered locally and not at all along its entire length with a high quality tape. The vapour barrier joints were glued with aluminium tape and many holes were created in the vapour barrier under the timber lathing. It is these holes that need to be treated well, as this is where the risk of water vapour condensation occurs, which will cause the thermal insulation to become damp.
Example of correct implementation
We recommend using green or yellow strong adhesive tapes for the correct implementation of the vapour barrier joints. All details of the correct implementation are shown in one picture from a real project in practice and in two illustrations.
Thorough securing and proper treatment of vapor barrier joints can prevent several complications in the future, so we recommend you to choose the correct implementation procedure. If you have any questions, please do not hesitate to contact us and we will be happy to advise you.
