Drying red oak

Is air drying, prior to kiln drying, a good idea? March 20, 2001

Should I immediately kiln dry northern red oak after sawing, or should I air dry first? I will be sawing 4/4 red oak in early March and have a buyer that will use 500 bf for baseboard and window trim in June.

Forum Responses
If you have a good kiln, you are always better to dry from green. If you don't have a good kiln, you are better to air dry first.

Air dry the lumber for a while, then finish the job in your kiln. Saw the lumber well. Use a sealer on the ends. Use proper stickering techniques. Use an overhanging pile cover. Monitor (daily) the condition and MC of lumber, with some samples. Be prepared to slow down the drying if need be. Allow yourself enough time (depending on the MC lost during air drying) to do a jam up drying job in the kiln to finish off the lumber.

The typical loss when air drying oak is about 12%. This is a potential loss, so nobody sends you a bill. Hence, it is easy to overlook these losses and say "That is just the way wood behaves." But, into the kiln ASAP will get you the best quality. And the $25 for energy per MBF is a small cost compared to faster drying and better quality, especially in a small/medium sized operation.

Gene Wengert, forum technical advisor

Red oak with high moisture content seems to have the tendency to mold quickly at the beginning of the charge. The high MC causes you to go slower at the beginning, so you can't get the temp up fast enough to kill the mold without checking your lumber. I suggest air drying for awhile to get your MC down.

There is indeed truth to the above, but it is more complicated--low airflow can contribute, high RH can contribute, and temperatures between 80 to 100 F can contribute. And these are the conditions inside the load of lumber, not necessarily those measured by a thermometer on the wall.

Gene Wengert, forum technical advisor

Considering your timeframe, I suggest some air dry time prior to kiln drying. It will not hurt the lumber at all, as long as the ends of the boards are sealed and the top of the stickered pack is covered to shed rain and direct sunlight. If you dry right from the saw, you may risk gaining moisture due to storage of the dry lumber for approximately two months.