Hello,

All the walls of my basement are below grade and there are no windows. Just a door and stairwell that leads up to daylight. The basement has 8' walls. The only good news is that, unlike most basemetns, this one stays very dry all year round except for July/August where the humidity might spike up to around 60%-65%. The rest of the year it is between 30%-50%. There is no water entering from the walls or floor. Nonetheless, there is a constant musty odor and I'm baffled as to what's causing it. The only explanation I can think of is that the walls are covered with fiberglass insulation wrapped in a poly type of paper similar to Tyvek. Could this be traping water vapor outgassed from the concrete walls?


I would like to remove the insulation and install some type of ventilation to control the odor and to mitigate a slight radon problem. Any suggestions? Thanks.

 

Dehumidifier bringing in 60 cfm of air will do the trick

 

there is a constant musty odor
the walls are covered with fiberglass insulation wrapped in a poly type of paper similar to Tyvek. Could this be traping water vapor outgassed from them
If you dont have a poly hanging on the wall against the cement then the insulation it can be damp. Have you put your hand in the insulation and feel if its damp???

ED

 

OK. But it really isn't that humid down there. Would reducing the humidity level from 40% to 20% really do any good? I would like to install a HRV and duct it through the rim joist to bring in fresh conditioned air. The air seems very stale. If I had a window that would be left open most of the time that would be the answer to my problem.

 

It doesn't appear to be damp. Althought I have not felt it. It definately is not dripping wet.

 

Bring the fresh air into the dehumidifier to dry it out and filter it before dumping it in to the home. This will put a positive pressure on the house bring in clean dry outside air and you can dehumidify your basement to. 45% rh is great for a basement