I’m trying to bring down the humidity in my garage shop, it’s about half insulated and I have an electric heater in it. I live in the Portland Oregon area so there’s plenty of humidity. I’ve had a problem with Sapele warping and twisting when cut into rails and stiles, the wood is at 6.5 %. I bought a temp/humidity gauge and the temp was ~60 with 49% humidity. I bought a Whirlpool 25 pint dehumidifier, ran it ~24 hours and heated the garage to 69 deg. and the humidity went down to 44%, which I would expect the relative humidity to go down with the temp going up. The dehumidifier had about one pint of water after 24 hours. So, is this about what is to be expected? Is the dehumidifier working, what level should it bring it down to? Is there a better way?
I was expecting better results.
mousejockey
Replies
A relative humidity in the range of 40-50% is generally considered to be optimum for living spaces, so you're in good shape. People sometimes intentionally reduce the humidity below 40% in order to control dust mites, but then you start getting into the "zapping" range.
-Steve
Your wood may well be warping because it is too dry for your environment. A relative humidity of 50% will cause wood to move to about 8-9% equilibrium moisture content. By lowering the humidity you will be causing problems when you later bring your item inside. At that point, it will want to absorb moisture to get to the EMC with the relative humidity in its new location.
What I would be doing--and I live in coastal North Carolina where we have high relative humidity--is acclimating the wood to the existing environment. Not trying to change the environment. I would stack and sticker it for a month or so where there was good air circulation to get the wood to 8-10% if my RH was in the 50-60% range.
I want to thank everyone for their comments, it sounds like I just need to sticker my stock for a while then give it a shot.
Thanks again
MousejockeyOver the Hill? What Hill? I didn't see any Hill!
MJ,
I'm 2 hours south of you and less than 1000 feet from low tide on a big pond. Outside, at this moment, RH is 81%. My RH inside is normally in the 50-55% range (gas heat) and I just have a small electric heater in the shop. You may be too dry. 44% sounds like Idaho desert.
John
your shop doesn't sound all that wet to me.
But if you need to keep it dryer, try sealing your (I assume)
concrete floor.
Concrete is very good at wicking moisture and sealing it can make
a very noticeable difference.
Less dusty too.
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