HOW IT’S DONE
This is how you process a vapour barrier
Vapour control and vapour barrier membranes are used to eliminate air flows and to protect constructions and insulation material against unwanted condensation. Air inside insulated spaces is normally warmer than outside air and can lead to increases in humidity. This can be caused by, for example, cooking or showering, although rainwater or elevated groundwater levels can also cause a lot of moisture, which starts to rise due to evaporation.
The created moisture will want to flow outside as vapor, which can cause condensation or construction decay if the wrong type of vapor barrier is used. But above all, moisture can cause insulation material to become moist, which means it will be less effective. That is why it is important to use a good vapour control or vapour barrier membrane to fully seal the inside of well-insulated constructions.
Attachment using staples
You can easily install vapor barriers with staples. Roll out the membrane and staple it in place under the construction. Because staples create perforations in the membrane, it is important to keep the number of staples to a minimum or to insert them where they will be covered by the next membrane overlap. To ensure an effective air seal, it is essential to tape over visible staples and overlaps using suitable tape.
Attachment with double-sided tape
If you want an airtight attachment without perforating the membrane with staples, you can also attach the vapor barrier with VAST-R® double-sided, VAST-R® Sealpro or VAST-R® Butyl tape. Apply the double-sided tape to the underlying construction, apply firm pressure and then remove the release layer. Roll out the membrane and press it against the double-sided tape. Carefully rub over the tape afterwards to ensure effective bonding.
Vapor barriers are placed on the warm side of insulation material. When installing the vapor barrier, it is also important to consider how the area will be used in the future. For instance, the vapor barrier could be damaged if placed directly behind plasterboard and when later on holes are drilled or screws are inserted. That is why we recommend placing a batten over the membrane, before placing the plasterboard for the final wall or roof finish. This means the membrane will be further away from the wall finish and will be less likely to be penetrated.