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I'm proposing to use one of these as the VCL on the reverse of two layers of plasterboard on the underside of a ceiling. Do I need to tape where the fixings will go through the membrane to secure the plasterboard, or will they not impact the airtigh...

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Unless you’re aiming for Passivhaus levels of airtightness, you don’t usually need to tape the membrane where the screws will be installed into the joists as this type of penetration is largely self-sealing. However, if when installing the plasterboard you miss the joist then I would suggest leaving the screw in place so that you don’t have a hole in the membrane.
If you are aiming for Passivhaus air tightness then you would reduce the risk of air leakage by using the Ampacoll ND Duo nail sealing tape on the underside of the joists first. This is a double sided tape so will hold the membrane in place until such time as the plasterboard layers are added.
Hope that helps.
Posted : 12/03/2021 1:15 pm

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