We have a 100 year old camp in humid Northeast that is closed for the winter. We just replaced the floor joists and subfloor and put a 6 mil vapor barrier on the dirt in the minimally ventilated crawlspace (2-3 feet), but it can't be sealed to the stone foundation and there will still be a lot of moisture beneath the floor. The floor is un-insulated. Can we put down a second vapor barrier between the subfloor and floor without creating moisture issues? Each side can dry away from the barrier so it seems that there should not be a problem, but the crawlspace vents will be closed in the winter.
All expertise appreciated.
If there is not a vapor barrier as finished floor, such as vinyl, I would be tempted to put foil faced foam underneath the new joists and tape the seams, drying occurs into the interior, upstairs. The joists will then stay warmer and are more protected from the damp air below. In a vented crawlspace the temperature of the joists can fall below the dew point of the incoming warm humid air. When this happens the moisture in the air can condense on the cool joists and raise the moisture content into the rot zone.