Clients often ask us whether prefinished or unfinished flooring is better. I would typically only recommend site finished flooring if you are trying to match an existing site finished floor and are refinishing the entire area. We do not recommend it for boards over 2-1/4” wide.
There is a misconception that site finished flooring is completely sealed and will not move. The fact is, wood will shrink and expand with changes in humidity, and gaps in a site finished floor are far more noticeable than prefinished. When site finished flooring shrinks in the winter, the gaps that develop will crack the finish, which is especially the case in wider boards.
Also, since the boards in a site finished floor are stuck together by the finish the gaps will develop at the weakest point in the finish which may be every 3- 4 boards. This is called “side bonding” and doesn’t occur in prefinished floors. In a prefinished floor the boards are free to shrink individually so you have small gaps between each board, rather than large gaps randomly throughout your floor.