Garage humidity in winter

[eggy]

I have a 2 car garage that we park in most of the winter. When we park the cars after a snowfall, the humidity in the garage goes through the roof. I'm getting to the point where I really want an "all the time shop" and am debating on what to do. I have a 16x20 shed that I built with the intention of someday making into a dedicated shop. That would be cheapest and easiest to do. On the other hand, my wife thinks it would be best to enlarge the exisiting garage and put more living room above (better resale value, etc.). I'm all for a larger garage that would have a dedicated shop area (about 12x36), but am concerned about the aforementioned humidity.

For those of you who press your garage to double duty, how do you deal with the fluctuation in humidty when storing your wood? Or better yet, how does it affect your unfinished projects?

[a1gutterman]

Buy a dehumidifier! I use one in my shop all the time, summer and winter. It really does a good job keeping the humidity where you want it. The better ones allow you to set the humidity level, tells you the temperature and combs your hair for you (just kidding about the combing:p ) If you are able to place it in an appropriate spot, you will be able to set it up to drain by itself; otherwise, you must empty the "bucket" when it gets full. You will be surprised at the amount of water it sucks out of the air! Another great benefit is it prevents mold from growing; a must for us allergy sensitive people.

[eggy]

Tim,

Would a de-humidifier handle a large fluctuation in a short period of time? After 1 snowfall, the garage gets so humid there is water dripping off the windows on the overhead door. This will only last for about a day if we don't get any more snow right away. Does a spike in humidity like that even effect the wood being stored or a project in progress?

[a1gutterman]

Hi eggy,

Tim,

Would a de-humidifier handle a large fluctuation in a short period of time? After 1 snowfall, the garage gets so humid there is water dripping off the windows on the overhead door. This will only last for about a day if we don't get any more snow right away. Does a spike in humidity like that even effect the wood being stored or a project in progress?

My first dehumidifier (a Maytag unit that went T-U after about 3 years of usage) sucked about 5-6 gallons of water out of the air in a day on days that were above 90% humidity. My basement is a 50' X 36' rectangle, 1800sq ft (625sq ft of that is my wood shop). Sucking the water out of the basement even keeps the humidity down upstairs in the house. At this very minute, I have 98% humidity outside, 40% in my shop and 31% upstairs. Before I used a dehumidifier, I had a bad mold problem in my basement. I now have none that I can smell or see.

I really can't say for sure, but IMHO, the spike in humidity probably does effect wood.

[Ed in Tampa]

I have a 2 car garage that we park in most of the winter. When we park the cars after a snowfall, the humidity in the garage goes through the roof. I'm getting to the point where I really want an "all the time shop" and am debating on what to do. I have a 16x20 shed that I built with the intention of someday making into a dedicated shop. That would be cheapest and easiest to do. On the other hand, my wife thinks it would be best to enlarge the exisiting garage and put more living room above (better resale value, etc.). I'm all for a larger garage that would have a dedicated shop area (about 12x36), but am concerned about the aforementioned humidity.

For those of you who press your garage to double duty, how do you deal with the fluctuation in humidty when storing your wood? Or better yet, how does it affect your unfinished projects?

In Florida the problem is the exact opposite. In the summer the humidity goes nuts. However I haven't noticed a big problem. I often store wood in my garage which goes from 90+ and high humidity to 70 and low humidity (when I turn the air on).

Frankly I think worrying about relative humidity and properly dried wood is a waste of time. I really don't think properly dried wood will absorb enough moisture out of humid air to really effect it. I know many claim that wood will warp but I think the problem was the wood wasn't properly dried to begin with.

That said I do know relative humidity does effect the drying process. If the relative humdity is high wood will air dry very slowly. But since I use mostly kiln dried wood I haven't experienced a huge problem.
Ed

[Bruce]

Frankly I think worrying about relative humidity and properly dried wood is a waste of time. I really don't think properly dried wood will absorb enough moisture out of humid air to really effect it. I know many claim that wood will warp but I think the problem was the wood wasn't properly dried to begin with.

If humidity has no effect on your wood, why do so many professional woodworkers say that's it's imperative that we let our wood acclimate to the environment of our shop before we work it?

[Ed in Tampa]

If humidity has no effect on your wood, why do so many professional woodworkers say that's it's imperative that we let our wood acclimate to the environment of our shop before we work it?

Bruce
I don't know. I don't have any scientific data but I do know people air dry wood here in Florida but also in Ohio, Alaska and California. Each location has differing humdity and temperatures yet the wood dries none the less.

I'm would really like to know how much a high relative humidity adds to the water content of wood versus wood in a stored in a low relative humidity.

I seriously wonder if it does. I tend to think it may effect internal stresses that are in every piece of wood just as temperature effects it, but I don't think it does much to actual water content of properly dried wood.

I allow my wood to season in my shop not to adjust water content but rather to allow the internal wood stresses that occures when the wood is cut, dried, moved, exposed to various humidities and temperatures to sort of settle out.

I'm not talking about pulling a piece of wood out of a pond and cutting it nor am I talking about taking a board that has been stored in -20 degrees.

Can anyone tell us exactly how the water content of a board is that was properly kiln dried and then stored in two different environments one with a low relative humidity and another with a high relative humidity?

I don't think it will be effected that much so I don't see gradual changes of temperature or humidity that occur in every shop to be a problem.
Ed

[charlese]

Well - The facts are that woodworkers need to be aware of the moisture content of the wood they use. Without going into much detail - a wood joint made with two pieces of unequal moisture content will almost assuredly produce an uneven joint when the piece reaches equal moisture content in the future. Depending on the thickness of the wood pieces and grain (rift, quarter, plain sawn) this unequal step can get quite dramatic.

Kiln dried and air dried lumber is supposed to be less than 15% to 20%. Wood in furniture in a house becomes 6% to 11%. There is, in fact a change in the shape of wood during this transition.

There is no wood that is a homogeneous structure. (unless is is man made from wood fibers) These unique qualities of wood make it mill-able, beautiful and also movable in size.

For more info. download this and review chapters 3 and 6. http://www.fpl.fs.fed.us/documnts/fplgt ... gtr113.htm

[james.miller]

Yes humidity matters, every book I've read about jointery stresses the importance of allowing for the wood to move with changes in humidity.

An extreme example of that happened here a few years ago. A gentleman retired after working at Edwards AFB in California and moved to Tucson. He brought his 1920s Willys sedan and moving from the Desert in CA to the Desert here where the climate is harsher, the wheels promptly fell apart. I've heard the story that Henry Ford used to have a factory here because the Model T wheels built in Dearborn would fall apart when they got to AZ.

Read Nick Englers book Joining Wood for a more technical description of how much wood can move with humidity.

[Ed in Tampa]

I think everyone is misreading what I'm saying. I'm saying that storing wood in a garage that has humidity swings does not cause a big problem. I don't think high relative humidity will raise the water content of the wood to a point where the wood is too wet to be used for furniture.

I know of no place on earth where the humidity stays a constant and there are wood workers working there and making things and they aren't all working in humidity controlled facilities.

Now we can discuss this all day but I live in an area that has huge humidity swings and I haven't ran into a problem.

Ed