I live in northern Westchester County, N.Y. My house is built above a crawl space with a dirt floor. Last year I had expanding foam insulation installed between the floor joists above the dirt floor. The height between the dirt floor and the bottom of the floor joists varies from a high of about five feet to a low of about six inches (the house is built on a slope).
I have heard conflisting theories about ventilating a crawl space. One theory says keep vents open in winter and closed in summer. That seems counter-intuitive to me.
At one end of the house I have a window opening to the crawl space measuring about three feet by three feet. In spring, summer and fall I place a screen in the opening. During winter a place a solid door in the opening.
At the other end of the house there is a small window (27 x 17). In spring summer and fall it is covered by a screen. In winter by a solid board.
Here's my question.
Should I cover the two aforementioned windows with the screen, or solid covering, in the spring, summer, and fall? What about winter?
Is it necessary to cover the dirt floor with polyurethane?
Thanks.