Interior walls

[Gullfiber]

I have erected the framework for the interior walls in the unfinished upper floor. The exterior walls are insulated and covered with plastic. The ceiling is insulated but not yet covered with plastic due to the electrical work. Before I sound insulate and cover the interior walls with plastic, I have the following questions:

When I cover the walls and ceiling with plastic, there will be an area above the wall plates that is not covered with plastic. Could this be a problem? Should I insert some plastic between the battens and the wall plates?

 

[nimhed]

You don't really need to cover interior walls with age-resistant plastic, do you? You do that between two areas that have a temperature difference, e.g., between the second floor and an uninsulated attic.

Besides, I don't think you need to worry too much about the small section that's not covered with plastic, but feel free to wait for more comments here on the forum.

 

[Gullfiber]

Ok, sounds hopeful.
Since we have an unheated attic above the upper floor, it might be enough to do the ceiling and let the plastic finish a few decimeters down the interior wall.

 

[nimhed]

Ok, sounds promising.
Since we have a cold attic above the upper floor, it might be enough to cover the ceiling and let the plastic end a few centimeters down the interior wall.

Yes, definitely. Let the plastic go down a few centimeters and you'll be fine. You do have adequate ventilation in the room, right?

 

[Mats]

As I understand it, you should not use plastic on interior walls. Then you risk trapping moisture in these walls and that's not what we wanted to achieve.

 

[Dregen]

To my knowledge, interior walls should not be covered with plastic, only exterior walls and roofs in areas that are heated year-round.

 

[Linnex]

Interior walls should not be covered with plastic. Therefore, you should install plastic on the ceiling and exterior walls BEFORE nailing up the interior walls to have the plastic completely covering them.

Plastic is placed on the inside of exterior walls/ceiling to prevent warm air from pushing through, cooling down, and condensing, which causes moisture problems.