Frequently Asked Questions

Q.   We have a perforated acoustic liner sheets to our roof, can the vapour barrier to roof be used as air seal line.?

Yes. However we would advise against it as particular care must be taken to ensure that there is a robust seal detail at the eaves junction to continue the air seal line from the inner face of the walls across the roof. Particular attention will need to be paid to ensure that any joints and penetrations to the barrier are fully sealed prior to being covered over as they will not be accessible afterwards.

We would advise specifying a rigid insulation board above the liner and using this as the air seal line. Care will need to be taken where the liner over sails external walls etc that air tight profile fillers are installed on the air seal line in the sheet troughs between the board and the liner.   

Q.   Should we use blockwork or dry lining to walls as air seal line?

Dry lining – As there may be expansion joints etc behind the lining boards that do not get properly sealed as they are not going to be on display. Additionally if the blockwork used has a high porosity then using the dry lining will reduce the problem caused by air leakage through the blockwork.

Ensure any exposed edges (Including where the lining boards finish below raised access floors and penetrations to the drylining are sealed.

Care will need to be paid to any areas of exposed blockwork above suspended ceilings, below floors and behind demountable panels etc that any joints, junctions and penetrations are sealed with air tight materials  

Q      Are acoustic/fire stop materials suitable for air seal?

Yes, if not porous – Rigid and foil faced boards and the pasted batt systems are suitable provided board joints, junctions etc are sealed.

Loose mineral wool is not suitable. Any compressed mineral wool system used say to wall heads should be overcoated with either intumescent or ablative paste for air tightness.