Hi. Welcome to Just Answer.
Maretin has asked that I jump in here and see if I can offer a solution to your problem.
I have set more manufactured homes than I can count. Some in the south where the humidity is high and some in the north where cold is a big factor.
If you have high humidity where you live then the condensation on the moisture barrier under your home is actually kind of normal. If the warm moisture laden air comes into contact with the moisture barrier and it is cooler than the ambient temperature then the moisture will condense on it.
It is just like a kitchen window during the holiday season. Moisture is going to form on it when the cooking gets going good. The cooking produces humidity and when it hits the cool window it condenses on it.
One thing that I have seen is some manufacturers used to use blown in cellulose insulation under the floor. It was cheap, light weight, and met the code requirements at the time. Today it is no longer code compliant. The reason being that it would settle and lose its insulating ability. The units that had it installed would begin to have problems just like yours. If the inside of the unit was kept cool during hot humid days the underneath of the home would look like a muddy swamp from all the condensation.
This could very well be what has happened to your home.
What I suggest you do is get a roll of gaffers tape (black duct tape. Its extra sticky strong) and a utility knife and go under the home and open up the moisture barrier where you think the most condensation is happening. If the insulation is the blown in type you really should have it reinsulated with regular batt type insulation. This will keep the cool air of the home from coming in contact with the warm moist air outside. That done the moisture will not condense on the barrier anymore.
One other thing here is the crawl space needs to be vented. If warm air is trapped under the home it can cause all kinds of problems besides just condensation on the barrier. Mold, dry rot, foundation subsidense (newer units), and rusting of metal jacks and other compoinents of the home. Ensure that you have good ventillation installed in the skirting, and that will eliminate most of the potential problems.
Please let me know if you have any other immediate concerns.
If not please select a positive rating at this time. Doing so will not close your question, and after you rate my service you may ask any followup questions you like. All at no additional charge.
Thank you for the opportunity to serve you.
**How to rate your expert**