I asked the question to KA about how to handle holes in the plastic (roof against the wind - loose fill) and he first says that you can just tape it. The problem is that the carpenters have installed battens crosswise (we're going to put paneling in the great room) and they have used screws that go through the first batten and those damn screws can make holes in the plastic BUT KA didn't think that was anything to worry about "screw and nail holes are everywhere in exterior walls where they've put boards, etc."
What do you think - is it nothing to worry about?
The reason I discovered it was that I was going to add a few lengths and got the idea to check that the screws didn't go through, which they did even though I screwed at an angle. Then I felt the battens the carpenters had put up - same thing there.
Kjell G
What do you think - is it nothing to worry about?
The reason I discovered it was that I was going to add a few lengths and got the idea to check that the screws didn't go through, which they did even though I screwed at an angle. Then I felt the battens the carpenters had put up - same thing there.
Kjell G
Obviously, neither your supervisor nor the carpenters are aware of the moisture investigation conducted already twenty to thirty years ago (I believe it was in Lund) which showed that 3% holes in a vapor barrier could lead to up to 20% more passage of vapor moisture where the aim is zero percent.
So the answer is, of course, that it is not advisable to perforate a vapor barrier, but it is done by various professional categories and for different reasons. Sometimes by mistake, sometimes fully intentionally.
In the past, electricians were the worst, how it is today I do not know. But I believe they are still the best at reducing the strength in roof truss bottom frames by drilling holes in the tension zone.
So the answer is, of course, that it is not advisable to perforate a vapor barrier, but it is done by various professional categories and for different reasons. Sometimes by mistake, sometimes fully intentionally.
In the past, electricians were the worst, how it is today I do not know. But I believe they are still the best at reducing the strength in roof truss bottom frames by drilling holes in the tension zone.
OK, now I think that there are actually fewer holes than I thought. It might be about 30 square meters that have been extra thinned, of which I've screwed some and what I've felt seems like the screws haven't perforated the plastic in many places. Even if they're sticking up, there's no load now, the loose fill was already in place and there's some flex in the plastic (hard to stretch it tightly) so I'm probably calm. But KA's attitude worries me, I trusted him completely, plus he's my builder (yes, completely against all recommendations), but this is the first warning sign and I've followed the process meticulously on my own.
The electrician, the poor guy, has had me on his heels the whole time; he's only been allowed to borrow the drill in exceptional cases, and I've put up most of the pipes and boxes myself. Otherwise, you never know - but they have probably gotten better at it in general.
Kjell G.
The electrician, the poor guy, has had me on his heels the whole time; he's only been allowed to borrow the drill in exceptional cases, and I've put up most of the pipes and boxes myself. Otherwise, you never know - but they have probably gotten better at it in general.
Kjell G.
Then it's like this, you can't compare nail and screw holes in the vapor barrier when it's pressed between two materials, e.g., between a stud and a wallboard, to when there's a "free" hole in the plastic. The problem with holes in the vapor barrier is mainly that humid indoor air can literally spray into the structure that should be protected from moisture, e.g., if there is an issue with the ventilation.Kjell_G said:
This opening for harmful airflow is not the case when a screw goes through the vapor barrier, when it must, to attach the gypsum board to the stud. There, the two screwed/nailed materials ensure that there can be no airflow.
But for those who don't fully understand the function of the vapor barrier in the wall, it's easy to say "but there are already lots of holes"
