Expansion and Contraction of Wood Flooring: What it is and How to Avoid It

Although there are many benefits of hardwood flooring, it is important to note that expansion and contraction of the wood is to be expected as weather changes throughout the year. As mentioned in a previous post, moisture and hardwood floors don’t mix well; wood naturally expands in moisture (such as when air is warm and humid) and contracts once the moisture is gone (such as when air is cool and dry).

How can you avoid expansion and contraction of your hardwood floors?

Here are a few ways to avoid expansion:

  • Maintain relative humidity of at least 50 percent in your home. Never leave the rooms with wooden floors without heat in the autumn/winter and ventilation in the spring/summer for long periods (3 weeks or more).
  • Allow excess moisture anywhere in the house to evaporate.
  • Do not install your flooring over damp concrete or wet plywood. Even if the wood is dry, it will pick up moisture from the wet sub floor.
  • Wash the floor with a slightly damp mop (not a wet mop) as water left on the surface of flooring for periods of time will be damaging to the surface of the floor and may cause it to expand.

Here are a couple of ways to avoid contraction:

  • Ventilate the area by opening a window
  • Heat the area to a moderate temperature

Hardwood floor expansion and contraction can appear in a few different ways:

Cracks Between Boards: These spaces are to be expected and usually close up as the season changes and moisture returns to the air. To reduce the degree of change, homeowners can add moisture to the air during the dry months, ideally by installing a humidifier in the furnace.

Cupping & Crowning: Cupping describes a condition in which the edges of a board are high and its center is lower. Crowning is the opposite of cupping: the middle of the board is higher than the edges of the board.

Buckling: Buckling happens when the floor literally pulls away from the subfloor, up to heights as high as several inches. Fortunately, buckling is an uncommon occurrence; it generally only happens after a floor has been flooded. Still, the floor can usually be repaired as opposed to replaced.

Think your hardwood floor has expanded or contracted? Contact us to find out what else you can do to minimize the effect in your home!

Photo courtesy of Somerset Hardwood Flooring