The crawlspace in a house I am working on has a moisture problem that I am at a loss to fix. maybe someone out there can help. The house is new construction and is insulated with corbond, however there is no insulation between the crawlsace and the first floor. The crawlspace is unheated, but does contain an electric hot water heater and associated hot and cold water pipes. The heating plant is a Rinnai, direct vent LP space heater on the main living floor. The floor of the crawlspace is a concrete/vermiculite mix sold under the trade name nuetocrete and, in theory, acts as a vapor barrier. Finally, there is no access to the crawlspace from within the house, you must enter through an outside steel door.
The problem is that the humidity is a constant 80% and anything in the crawlspace mildews quickly. Also, in winter months, the interior portion of the foundation that is above grade forms condensation as does the insulated steel door to the outside entrance.
It seems to me that anything done to ventilate the space is going to cause pipes to freeze and other bad things. Any ideas?