I am from Mississauga, Ontario, Canada. Would someone be able to just give a rough estimate (I know it varies a lot, but I am just looking for a range of the cost) on how much I am looking into if I want to take out a separate entrance for my basement apartment. Learner2

I have a 1930s bungalow that has a high level of humidity in the basement/crawl space. The basement is mostly earth except for a 20x15ft area of concrete floor where the utilities are. There are several foundation vents around the perimeter of the house, though I've never exactly felt a breeze down there. I'm concerned about the wood structure (joists, subfloor, etc) as high humidity can't be good for it, I've also noticed some small patches of mold in some joists, though there doesn't appear to be any rot or infestation (yet). What would be a good way to proceed with this? I am looking at the following options: 1. Adding an exhaust fan on one of the vents to increase airflow. 2. Put in a dehumidifier 3. Put down 6mil polyethylene sheeting over all exposed earth areas. 4. Stop worrying about it. After all, this house has survived this long without any solution, maybe its just supposed to be like this? The area that I live in (Atlanta) has very high humidity outdoors, so I was worried that installing an exhaust fan on one of the vents might in fact draw in *more* humidity? I like the dehumidifier idea, but wonder how effective it would be since there are foundation vents? Like I said, I don't feel a lot of ventilation going on down there, but there must be some (it doesn't smell bad). Furthermore, I would have concerns about blocking up the vents as it would then confine any radon or other gases into the house. Should I buy a dehumidifier? Laying down the 6 mil poly seems like a good idea, but our inspector (when we bought the house) said it would not be necessary in this case (why, i'm not sure). Any advice or suggestions would be greatly appreciated. thanks, Ryan