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help...stale wood smell

Posted by coeng (My Page) on
Wed, Aug 8, 07 at 13:51

Every summer when the heat and humidity really picks up, my basement smells like stale wood.

I have a drop ceiling that covers all of the basement except for the pantry, the closets for water and gas meters, and the boiler room.

Every time I move ceiling tiles to run new wires or replace flourescent bulbs I get a whiff of it. Its must be coming from the joists or the floor boards above.

Is this normal? Is there anyway to get rid of the smell? My house was built sometime in the 60s. Its a Cape Cod and the basement is finished.

I don't have any kind of ventilation but I do run my basement A/C periodically throughout the day to keep my basement from getting too hot and humid. Not that this helps much since no air gets directed above the drop ceiling.

Any help would be appreciated.

I can take photos of my basement if it would help solve the problem.

Follow-Up Postings:

RE: help...stale wood smell

The odour is of mould being reactivated every summer with all the humidity that is entering the basement. The AC encourages the entry of water vapour, which always goes from hot to cold areas.

You should be running a mechanical dehumidifier in the summer months. After 40 years of overhumidification, you may have to treat the mould as well.

RE: help...stale wood smell

I don't see any mold when I look at the joists though. How can I treat mold that I can't see?

Also, how can the A/C encourage the entry of water vapor into the space above the drop ceiling? Doesn't the drop ceiling prevent this from occuring? Wouldn't the joists be moist to the touch in that case? They're bone dry.

Running a mechanical dehumidifier in the basement without having the A/C on makes it really warm down there. And I really don't want to run two energy-hungry devices at the same time. I only run the mechanical dehumidifier when I want to quickly get the humidity down in the basement and I only run it in conjuction with the A/C.

If my thermometer/hygrometer registers 77 degrees and over 70% humidity, I usually turn the A/C on. After an hour, it drops down to about 58% humidity. This usually makes running the dehumidifier unnecessary. With the dehumidifier on, it may get as low as 52% humidity. However, if you shut the A/C off, it doesn't take long for the humidity to return.


"Moisture becomes heavier as it cools and settles to the lowest point in the home. "

Just read this on a basement website. It appears to contradict worthy's statement, or does it?

If I had a moisture problem (amplified by the use of the basement A/C) it would seem that the problem would be on the floor and not in the ceiling.

Could the stale smell be just from the lack of air circulation in the ceiling as well as the heat that seeps into it in the boiler room (there is no drop ceiling in that room for the obvious reason).

I will take numerous photos tonight and post them tomorrow.

RE: help...stale wood smell

Most experts suggest basement humidity levels be kept between 30% and 50%. Keep it there. Don't just bring it down when it goes up.

Air travels from hot to cold areas. (That's why vapour barriers are incorporated on interior walls--so that in the winter, warm vapour laden air from inside your home doesn't easily create moisture in your walls.) A/C makes the basement cold. That's how it promotes moisture infiltration. Though at the same time it does reduce some of the moisture it encourages in the first place.

Can't see the mold? As the linked EPA publication shows, mold can be hidden in many places. Also, even dead mold can have an ill effect--or at least leave a bad odour.

The need for dehumidification in most climates is explained in the technical documents available from the Building Science Consortium.

Here is a link that might be useful: EPA Guide to Mold

humidity in basement

My basement is relatively dry 8 months out of the year. In fact today (its really nice and dry outside for some reason) the humidity is only 59% and the A/C and dehumidifier are off. In fact, in the winter it gets much drier than that. That's probably because the basement is not completely below grade. My garage door which connects to my basement is at grade level. The reason humidity seeps into the basement in the summer months is because of the window unit A/C. It just naturally seeps in through the vents when the unit is off even though the vent on the A/C unit is closed.

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