I have a bit to add to this and another question about venting. Since I started this thread, I have learned a little bit. First off, I went into a Lowe's store where they sell this particular ridge vent. I looked closely at it and I can see that on the underside, there is attached a thin fibrous gray paper or fabric like underlayment. So I went up into my attic where I can see all of the vents and I find that over my living area, the vents are installed correctly which is a huge relief. I can see the fibrous underlayment there. BUT, I have an attached garage and carport, this is where I had first noticed the plastic underlayment because it's right at the top of my attic steps. Above the garage, I looked at the entire length of the ridge vent and the whole thing is showing the plastic roof underlayment, so apparently they forgot to cut it out before installing it. Another thing that is concerning me is that the old ridge vent was longer than the new ridge vent so when I questioned him after the roof was done, HE said that it is OK to be shorter and that an un-airconditioned and un-heated structure is NOT required to have a vent at all. I am in the state of Ohio, does this sound correct to y'all? Could it be OK to not have any exhaust vents in the attic of a garage? BTW, the garage and house attic are opened to each other.
The contractor is going to come look later on this afternoon. I'm sure hoping that he will admit his mistake and get this fixed. I will let y'all know when I find out what he says.