Kiln Dried Lumber

[Joe Vee]

Greetings Everyone,

I had a question regarding professionally kiln dried wood. If I purchase Kiln dried boards and stack then off the floor (in an unheated building) will they pic up a lot of moisture up to 20% reading on moisture meter? Is there a way to keep wood dry until it is ready to be used? Running a fan across the wood? I need to keep the moisture content down (between 6-8%) for making molding. Thanks for the help

Joe

[Anthony Whitesell]

Now that you mention it. I do the same thing. My project specific stock is 1" from the floor with 1/2" stickers throughout in a designated pile. the rest of my 'generic' stuff (ie. left overs from previous work) is stickered and stacked on the shelves, far off the ground. I once read the best way to store plywood was between two sacrificial sheets of cheap-o OSB plywood.

[Stan Urbas]

OK, chew on this a bit. Virtually all the lumber you buy from lumber yards is professionally kiln dried (unless sold as "green"). So what happens to it next? I'm assuming you're not buying it right out of the kiln, right? I get my lumber from a well-known local lumberyard that has many kinds of lumber. It's all KD and it's all stored in an unheated, dry building. Much of it is there for months. Even if you buy it from a big box store, where it's on the rack in a heated building, chances it was in an unheated warehouse prior to that. I've even asked the lumber yards about this. Basically they will tell you that the wood will adjust to the prevailing moisture content of the air the the part of the country you live in. I've never had any problem working with this wood. So when I bring it home and store it in my unheated basement, should I be concerned? Not really. Never been a problem thus far. Now this is assuming that you don't have a leaky roof or standing water in the storage building.

A bigger concern for me is if I buy wood in eastern Washington, which is very dry, and bring it back home west of the Cascades. I really need to let it set several months to bring its humidity UP to our level before working it. On the flip side, I've made furniture for my daughter in the Denver area and was very concerned about the wood moving when it dried out. Again, no problem came as a result.

Bottom line: I think you're worrying for nothing.

[Peter Quinn]

Hate to reference another site but if your looking for good science check out posts by Dr. Gene over at woodweb. He has a lot of technical explanations regarding what happens to wood during storage and the effects of relative humidity and other environmental factors on KD lumber.

I think after chasing the science trail a while you'll find it is more about working wood that has reached equilibrium with its environment than hitting an exact target moisture %. The traditional sticker and wait advice is not bad. At least the wood may stay stable in your shop long enough to work and join effectively.

I worked in a millwork shop making moldings and flooring. Typically we shipped orders and advised they be allowed to rest in the space in which they were to be installed for two to four weeks to acclimate. The relative humidity of our shop could easily have been different than the homes in which the products were to be installed, and like it or not the wood is going to move as adjusts to its new environment.

I try not to store wood I am going to process shortly too close to the concrete slab is it seems to create its own micro climate which is fairly humid in my case. 6"-8" seems to work for me.

[Matt Ocel]

If you are storing it on concrete - Lay out some poly first then stack your lumber on some doneage and you should be alright. Remember, sooner or later your lumber will be affected by the air humidity. Also watch out for abrupt change of temperature. When I was a job sup. in winter months we would have a house or two that would loose heat over night in the winter and loose 20 to 25 degrees. If we brought the heat up to fast it would pop open mitres.

[Jim Becker]

When stored properly, your KD lumber should only acclimate to the MC that reflects local conditions, but that should generally never be more than about 10-12% MC. You want it at least a foot off the floor and up higher is better, IMHO.