Wood shrinks and swells with environmental changes, therefore some preconditioning of wood siding is necessary for best installation results.
When installed in a heated room without being preconditioned, siding may be expected to shrink.
Knotty grades have a higher moisture content than select grades
NOTE: A 4% moisture change in a board will case a width dimension change of .5% to 1% which may seem minor. But a 1% change across a 60 foot wall is 6 inches- a major difference.
Shrinkage can be minimized by conditioning the siding prior to installation. A) Stack all siding in the room in which it is to be installed with separation (using separator sticks) between each layer for a week to 10 days prior to installation. Plan your timeline accordingly! B) Separators must be linted up one above the other with weight placed on the top of boards to minimize cupping.