Do efficient homes create damp basements ?

By Glenn Hooper March 30, 2015

Short answer, No. Sarcastic answer, moisture creates damp basements.

That’s not to say there isn’t an increase in the number of new homes that suffer from moisture buildup, sweating walls and worst case, puddles in the basement.

So what gives, what’s changed ? How can efficiency above the basement cause the increase of moisture related issues below ?

Building science teaches us that one change can affect many other things. One of the things all efficient homes have is much tighter envelopes… As air sealing prevents heat loss and to a much lesser extent cooling losses by infiltration. Certain times of the year, mid spring or so, it can get pretty cool at night and warm during the day. This creates a few hours where any late morning or afternoon humidity literally jumps out of the air and sticks to the basement walls. Older homes don’t suffer so badly because the humidity is often pulled up and out of the basement the night before. Remember, at night the heat is on, which creates the stack effect. The stack effect depressurizes the basement in loose homes, but tight homes aren’t as connected to the basement. The moisture builds and builds in tighter homes. Pretty simple cure though, add dehumidification.

Besides loose homes, loose ducts mask basement humidity by pulling or pushing the humidity in or out. Again, pretty simple cure, Just add a dehumidifier in the basement and don’t be silly, add a $40 dollar condensation pump to the dehumidifiers tank. Most if not all dehumidifiers have a spot to hook up a short section of garden hose, just put the other end of the hose into the pump, place the pumps drain hose out of the home or into the waste line and never empty the bucket again.

Lastly, moisture is by far the number one cause of failure in a home. Moisture causes 80-90% of all home repairs. Getting rid if it before its sent through the home is the smartest thing you could do.