[Mark / Ohio]

... However, the seed was planted and now Judy is convinced that mold is taking over the house.....

Too much moisture inside condensing inside the external walls with the cold temps we've had this year? Surprised you would have that much moisture to deal with there. They make whole house dehumidifiers and also some heatpump systems with operate in a dehumidify mode cycling the AC and heat. I think that would be a pretty costly way to dump humidity though. Or is it just a lack of fresh air in the house issue?

I don't even know the current codes here. This house was built 30 years ago and what was good then is not so good now.

 

[Mark / Ohio]

Here's a document from April Aire: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCcQFjAA&url=http%3A%2F%2Fwww.aprilaire.com%2Fdocs%2Fdefault-source%2Fdefault-document-library%2Frelative-humidity-defined.pdf%3Fsfvrsn%3D2&ei=bzAYVfG6M4mfNp3Xg_AL&usg=AFQjCNFDZi2G29Wyd3Uj3ft2nO5hEVKsOg&bvm=bv.89381419,d.eXY&cad=rja

This house has 2x4 walls with fiberglass bats and a plastic vapor barrier inside behind the drywall. Ceiling has about 15" of rock wool and no vapor barrier, attic is open ventilated year-round to keep from building up moisture there.

My sinuses don't like low humidity levels so we run a humidifier during the winter. But depending on outside temperature I have to be careful not to get too carried away with it or I start sweating even the double pane windows. Seems like about 30% max on the zero degree nights and 35% when 20°F and above works best for me. Only place that I know of that I have some condensation is between the floor joists in the basement above the sill plate. They did not put any moisture barrier there and during the cold weather it sweats and gets some mold on the wood. Drys out once the weather warms up. I bought some insulation with a vapor barrier on one side to put up in there but have not got it done yet. I did get most of the air leaks around there plugged with canned spray foam.

One plus to a leaky house is once you heat the cold air that is infiltrating back up the humidity level drops as it is heated. Warm air can hold more moisture then cold air. Course during the summer the opposite happens with AC when the cooled air cannot hold all the moisture it could when it was warm and the excess sweats out on the AC evaporator coil.

Having a house in a far Northern climate with too much moisture to me means you did a very good job of insulating. :2th: I have no personal experience with them but an air to air heat exchanger probably be the cheapest way to get rid of the excess humidity and as a side benefit keep the inside air from getting stale due to the very low amount of outside air infiltration.

:2cents:

 

[Mark / Ohio]

One block of 12 above ground here. Good and bad with that. The ground is good insulation against cold and heat. Bad is in this clay soil that's more weight against the wall expanding and contracting as the ground moisture level fluctuates trying to push it in. At some point I think I'm going to need to add a couple vertical steel reinforcing beams to the East wall. The builder added beams to the North Wall in a couple places right after the house was built. Right after the wall was back filled we had several inches of rain which settled out the soil immediately and opened up around an 1/8" lengthwise crack in it literally overnight. Pretty common problem around here and they never seem to get better with age.