ᐅ Vapor barrier - counter battens in drywall construction: yes or no?

Hello,

we plan to do the drywall installation ourselves in the attic. There is a vapor barrier installed beneath the rafters. The roofer and the electrician both advised installing a counter battens system along the rafters and then fixing the support battens at 90° to them. Their argument was that the function of the vapor control layer could no longer be guaranteed if it is installed without counter battens, due to the adjustment screws, and that the gaps or holes in the vapor control layer would cause it to lose its effectiveness.

The drywall installer thinks this is not a problem.

Even after researching online, there is no clear consensus. Therefore, I wanted to ask for opinions here.

Thanks in advance!

Hello,

any penetration of a vapor barrier should be avoided.

If you use counter battens, you can install a nail strip where you screw the battens, thus sealing the penetration points.

Your drywall screws then do not come into contact with the vapor retarder.
Even if you find someone who shares your opinion, you should choose a construction method that does not compromise the function of the vapor barrier in any way.

If your method ensures that every penetration point is properly sealed according to plan, choose that approach.

Best regards,
Jann St

Did I misunderstand something? This is an insulation between the rafters, and the vapor barrier membrane is placed directly on the rafters? The drywall panels then don’t need leveling screws, and the regular screws go straight into the rafters. But every additional screw, whether for a lamp or a picture, will penetrate the vapor barrier membrane. I would install OSB or at least a regular chipboard panel under the drywall anyway, along with a battens laid perpendicular to the rafters.

I used counter battens, which worked quite well since I still had many slats left over from the renovation.
Thanks for your tips!