The intended purpose for laying down plastic is to retard the transmission of soil vapor (which is in almost all soils except in extremely arid areas, and inexorably rising due to changes in barometric pressure) from coming up into the basement space. The fact that you are using a dehu means that you have a perceptible soil vapor problem (at least that's why you are paying the electric co. to run the dehus, which is comparable to running an A/C, in some cases). Note however, that I said retard, not completely prevent the rising of soil vapor into the basement atmosphere. Nothing I know of will completely keep it out. Because we now have a goal of sealing up our houses in the name of energy savings (and have modern, and different, whole-house heating systems) rising soil vapor can get stuck within the building potentially causing damage to the structure or contents or residents, if mold develops. Of course your house, like mine, was built with long-tested systems that did not expect, or require, the house to be as hermetically sealed as we sometimes try for these days. In 1857 the vapor was a-rising just as it is today, but it was exiting the building much more easily. Two other factors: people lived and worked at home and were more likely to be aware of and able to adjust the basement openings during the day, promoting additional passive ventilation to remove the moisture. And they may have highly prized that very same moisture if they stored food in the basement. Of course they also didn't have nifty stuff like cross-linked plastic molecules made into cheap (if you don't take into account any off-stream environmental costs), easily laid-out rolls of plastic to put to use, either. Soil vapor is also coming from the basement's walls as your inspector noted. But blocking that moisture is as hard as, or harder, than blocking the soil vapor. If you had thoughts of converting your basement to modern uses (family room, media room, exercise parlor, etc.) you may be disappointed as this is rarely successful in old houses such as ours. So the remaining issue seems to be: how tight is the house above the basement, and how might that tightness be interfering with the house's natural ventilatory patterns. (I think of it as how the house is "breathing", albeit in a passive way.) And of course, it also depends how much more you may be planning to do, in the name of energy conservation, to further tighten up the house. You have run smack into one of the central dilemmas of old-house care: how do you integrate (without doing damage) modern building and energy standards with a structure that was designed and built to support a completely different system? Solving one problem can easily create a new, perhaps more difficult to manage, unforseen issue. There are many opinions and oxen-to-be-gored in this arena. As a practical matter, if you want to lay down plastic (though I recommend special-purpose materials intended for vapor retardation instead of construction poly) and can seal it well with tape where sheets are overlapped, and along the bottom of the walls, you can susbstantially reduce the amount of rising vapor within the basement cavity. But you should know there are some who posit that doing so will shift this moisture (perhaps with damaging consequences) to adjacent soil spaces, including under and in the immediate, exterior vicinity of your foundation walls. This (according to some) may super-saturate the soil, disturbing the necessary firmness and creating settling or susidence problems. Does it? I surely don't know, but it does create - over time - a very moist soil under the plastic. (You can test this by laying a yard-square scrap of plastic on the dirt floor and see what happens.) Others recommend various systems of forced, or air-pressure augmented passive ventilation to remove the moisture laden air from the basement before it can rise into house interior and replace it with (theoretically) drier exterior air. This method has the advantage of not monkeying around with existing soil mositure states, but it is complicated, and may take personal attention to adjust during each day and/or electricity to run. If you have just purchased this house, I think you should observe the ebb and flow for a while (at least a calendar year), as you think about this. And keep the issue in mind as you contemplate any further sealing and insulation projects. It sounds as though the dehus are keeping things in check, so nothing (except cost of power and fuss of removing condensate) is lost by taking a go-slow approach. And by all means, test for radon if you have it in your area. (Your local or state health department is a resource on this.) An upside of the necessary ventilation to control radon can be a reduction of basement moisture since the gas and at least some of the air vapor are removed at the same time.

Castor oil is very sticky feeling, nothing like an oil like olive oil. I use jojoba if I use an oil, it's thin and I can put my mineral makeup on top of it. It doesn't smell. I suppose you could use castor oil as a spot treatment on small spots. You can't really put it all over your face because it doesn't spread like an oil. The smell is minimum though. I bought it to put on my brows because some say it helps make them grow thicker but I've not kept up with it enough to really know if it works or not for that.

If the bathroom gets only minimal use, and the high relative humidity is an ongoing issue, the root cause isn't likely to be poor ventilation during or after a shower. A couple of things to consider: 1. Moist air is more buoyant than dry air so it's typical to have higher relative humidity on the upper floors of a home. Get a hygrometer and check the relative humidity in the bathroom so you know the baseline. 2. Check to ensure proper performance of the 2nd floor HVAC system. If the 2nd floor is normally unoccupied, you still need to operate the HVAC to dehumidify the space. 60% is the top end. I like to maintain relative humidity at 50% or less to limit the potential for mold/mildew growth. 3 Keep the bathroom door open when the bathroom is not in use. There aren't HVAC returns in bathrooms (returns are prohibited by code) so return air flow relies on the undercut in the door which is usually inadequate. 4. Ditch the fan(s) in that attic. Operating them can change the pressure balance in the home and pull moisture into the home from crawl spaces, stud cavities, etc. 5. Check for moisture sources like a damp crawl space or basement. Seal any sources of air leakage into the bathroom from the attic. 6. Make sure to operate bath vent fans when showering and a range vent hood fan when the range is in use to vent moisture from those sources to the outdoors.

Thank you for the replies! Maybe we need to re-think this. I'm not sure if the exterior of this wall has any moisture barrier on it. Since the downstairs sits underneath only about 2/3rds of the upstairs, this particular wall is not on the perimeter of the house. Instead, it is like a beam under the center of the house, and about 7-8 ft tall. He is also planning to take steps to reduce moisture on the exterior of this wall (under the house) by installing a french drain around the perimeter of the house and adding a few ventilation holes on the sides of the perimeter foundation just above the ground level. The musty odor is only near this one wall. The other rooms downstairs have sheetrock over the concrete (I assume with an air gap and bat insulation between the sheetrock and concrete wall) and do not smell bad. I was assuming our proposed solutions would allow moisture to either a) dry slowly in the air gap without entering the interior space (option 3), or b) stay in the concrete and eventually dry to the exterior in the summer when the dirt dries out (option 1). Maybe these aren't good assumptions.