Kiln Dryed Moisture %

[panlanrs]

I have air-dryed quite a bit of lumber and can normally get it down to 10 to 14% moisture. I go to my local building supply and buy kiln-dryed lumber that is stored in sheds outside and it is also 10 to 14% moisture. What is the advantage of kiln drying ?

[jdonovan]

The advantages that I can come up with right off the top of my head.

The kiln operator can control the drying schedule
Setting of pitch on softwoods
bug/egg killing
mold/mildew growth control/elimination

A large commercial operator would have to have a HUGE covered area to hold all their production for 8-12 months to get it all dried before selling it.

[WDH]

You are right in that it does not help for moisture control to kiln dry lumber then store it in an outside shed.  It will equilibrate to the outside environment.  However, as pointed out, there are other advantages to kiln drying. 

[Planman1954]

The advantage (and the reason I built my solar dry kiln) of kiln dried lumber is to make stock which is suitable for interior use. I've just finished drying my first load of lumber (beech) which I'm about to sell to a local cabinetmaker. It had air dried all summer, and measured 10% mc before I put it in the kiln 2 weeks ago. The first week, it was down to 8%, and now it reads 6%. The temperature in the kiln was well over 150 degrees on some of the days, and therefore killed all remaining bugs and larvae. I feel comfortable selling the stock to the cabinetmaker. I would not have sold it had it been air dried only. If he will keep the lumber inside a dry environment until it is used, so much the better. If left outside, it would regain some of the moisture content.

[Ironwood]

 This is my opinion of the matter.

 A very critical difference in the two is that KILN dried lumber will have "bottomed out" and likely collapsed all the moisture in the cells where AIR will not have done this. Once it gets into it's final indoor environment the KILNED stuff will quickly reacclimatize the air dried will still take a loooong time. All lumber left in ambient air will land at around 10-13% (at least here in Pa.) and kilned will reabsorb some moisture, and the air dried will "land there", but that is two very differing 10%'s
 IMHO,

 Ironwood

[SwampDonkey]

If you want to do any steam bending, don't even bother trying to use kilned. 10 % is what it is no matter if it's kilned or air dried. The difference is what it does to the wood. It's being cooked. It's not up to water boiling temperature, but it's pretty close.