What causes gaps or cracks in wooden floors? Wood is a natural product, so is sensitive to the environment it is kept. Because of this, almost every wood floor will endure some expansion and contraction as seasons and humidity levels change. When homes are heated, humidity levels plummet, causing boards to shrink and spaces to appear between the boards. In very dry months, cracks can easily develop to the thickness of a thumbnail, for example. With lighter coloured woods, the gaps and cracks may appear larger because of the contrast between the gap and the colour of the wood. Square edge boards will also show cracks more. These spaces are to be expected and will usually close up as the season changes and moisture returns to the air. To reduce the degree of change, home owners can add moisture to the air during the dry months, ideally by installing humidifier or by buying some potted plants! What if I want a floor that looks more worn and weathered? Some flooring products come with a worn appearance. While gaps and cracks are undesirable, these floors are as structurally sound as all other flooring products but have a more lived-in, authentic appearance.