Use kiln for steaming Home Kiln theory General theory Steaming lumber.

Using a regular kiln for steaming is possible, but not adviceable, since it is not as efficient as a dedicated steam chamber and your quality (color) will probably vary more. In addition, a kiln is normally much larger than an steam chamber and most lumber companies can rarely fill up a complete kiln with lumber for steaming.

Here are some of the major problems with using a kiln for steaming your lumber:
Wasted space.
A smaller closed room with little free space will require less energy and make it easier a high relative humidity in the chamber.
Not designed for live and constant steam pressure.
A steam chamber is exposed to a constant steam pressure on all the walls, ceiling, joints, etc. in a way a kiln is not. This will normally result in steam penetrating into the walls and ceiling insulation.
Too big.
Most lumber companies cannot fill a regular kiln full of lumber, which need steaming. Also, even it you could accumulate sufficient quantity, it will probably take several day. This is not optimum, since the best steam result is achieved if the steaming process is initiated within 24 hours of being sawn.