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You never had condensation on the plastic vb before as the temperature was a lot colder than it is now because you are gaining heat from the lack of insulation. The dirt is the coldest/closest area where the warmed, moist air is going to; http://buildingscience.com/documents/insights/bsi-049-confusion-about-diffusion
Add new insulation. Fiberglass will sag over the years, and compress from its own weight; especially if a vapor barrier facing is present (more weight= sags fast) and lack of wire supports to hold it up. Use string next time, or a housewrap, or better still-- add foam board to the joist bottoms; Fig.7; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/ May need an ignition barrier, depending on crawl access...
You need the facing if an older house with diagonal solid wood sub-floor and no plywood (with glue layer as a vb). First fill ALL holes in the floor above where wires/pipes enter to above- some go clear to attic. Metal around the bathtub drain to deter rodents. Good time to shoot some low-expanding canned foam under the tub for support/warmth during a bath with a straw extension.
Gary
You never had condensation on the plastic vb before as the temperature was a lot colder than it is now because you are gaining heat from the lack of insulation. The dirt is the coldest/closest area where the warmed, moist air is going to; http://buildingscience.com/documents/insights/bsi-049-confusion-about-diffusion
Add new insulation. Fiberglass will sag over the years, and compress from its own weight; especially if a vapor barrier facing is present (more weight= sags fast) and lack of wire supports to hold it up. Use string next time, or a housewrap, or better still-- add foam board to the joist bottoms; Fig.7; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/ May need an ignition barrier, depending on crawl access...
You need the facing if an older house with diagonal solid wood sub-floor and no plywood (with glue layer as a vb). First fill ALL holes in the floor above where wires/pipes enter to above- some go clear to attic. Metal around the bathtub drain to deter rodents. Good time to shoot some low-expanding canned foam under the tub for support/warmth during a bath with a straw extension.
Gary
