Expert: Bruce E. Johnson - 1/27/2009

Question
Good day! Our home is 11 years old. We have always had wet windows. They are wet on the side in our home not in between the windows. This was our first concern, then we realized that our siding was coming off, and need to have this replaced.Over the weekend my husband noticed that our knee walls in our basement had ice forming on this inside of them and were wet, we were recently told that the reason was because our attic was not properly ventilated and therefore would be causing the condensation in the home.  Could this be the reason why the knee walls and our windows are like this?  What should we do to fix the problem?  I thank you very much for any advice you may have. Thank you

Answer
Hi Natasha, first of all do you have airconditioning?  If so, do you use it or have a dehumidifier?  Interior house moisture is caused by moisture in the air which can be eliminated by proper conditioning.  Maybe your air conditioning isn't working properly.  Normal humidity levels in a house should be around 45-50 percent.  An inexpensive gauge can be puchased at most hardware stores to check your humidity levels.  A test and balance on your airconditioning can determine if your air is being returned to the unit and treated properly.  The latest project I have just completed has no attic ventilation.  The rafters are insulated instead of the ceilings.  The attic air eventually becomes conditioned space.  This seems to be where building designers are going.  The reasoning is that ventilation in an attic pulls outside humid air into the space and it accumulates causing condensation problems.  Does your home have a vapor barrier on the exterior such as Tyvek house wrap?  This helps keep moisture from penetrating into the living space.  Is there a vapor barrier on the ground underneath the house?  A thick layer of visqueen 6-8mil will stop moisture from coming up through the ground and into your living space.  We not only put the visqueen on the ground but take special tape and tape all the seams and around all the penetrations so that all that rising moisture stays in the ground where it belongs.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com