[City Girl]

We have a vacation house in the mountains. It has a stale odor throughout the house, not musty or moldy - almost like paint. Clothes lying out smell of it when I bring them back to the city. I don't notice the odor much while in the house but more when I go out and come back inside.
We used to have painted plywood floors which we covered with new Pergo throughout.
We vent the basement with an exhaust fan, and vent the house with open windows and fans while there also.
Besides this smell, we had a FISHY odor in the main bathroom. It was an old bath so we had it redone and gutted. It was discovered that the electrical wiring was nearly all chewed up to the point of a fire hazard. There were dead mice in there as well as a rotted joist. There is a small stream right behind the house where the bathroom is.
There was an adjoining open closet in that large bathroom which they closed as a separate closet apart from the bath. Now, the closet has the fishy smell and it sometimes stinks up the entire bedroom. I have to keep the door closed but still smell it. I assume the wall behind there might have the same issues the bathroom wall had. The contractor is supposed to come back and check things out under the siding back there.
I no longer look forward to going to our vacation home due to these odors. I have a mild lung disease so worry about that also. So far no worsening of my condition has happened in the eight years dealing with this. My lung doctor advises using a HEPA filter.
People say I am too sensitive to smell, so I am beside myself with this issue. If there were no odors, I'd love it!

[joypulv]

Fishy odor is usually associated with water drainage and venting.
Dead mice as you probably know have a distinctly different smell (that makes me gag).
Can you look in the basement under the closet to see if any pipes run there? Where does the vent come out the roof? Has anyone ever gone up on the roof to check the vent to see if it's clogged with leaves or animals?