Every floor in a heated space will endure some separation. This seasonal movement is a normal characteristic of wood flooring, and it never stops, regardless of the age of the wood. In the winter when the heat is on the humidity indoors decreases. This change causes the wood to shrink and cracks get larger. The gaps in floors of light colored wood or white stained floors tend to show more than gaps in darker or natural colored wood floors. Radiant floor heat and flooring around heating ducts can be more affected. Controlling the humidity is one way to minimize the seasonal shrinkage of wood. Normal relative humidity levels of 30%-60% should be adhered to in order to avoid cracking and drying of the wood.
Properly installed flooring may consequently experience some separation between boards and/or may also, in extremely dry areas, extremely humid areas or with excession of maximum surface temperature, experience some cracks on the surface.
Solid Wood Products does produce its flooring with a moisture content (MC) of 6-8%. If floors are dried down below 6% (by dry room climate, low relative humidity, improper use of in-floor radiant heating systems, excessive heating etc.) it may cause cracks on the surface and more gapping. Generally the wider the boards the larger the gaps.