During the winter months, the relative humidity (RH) in our homes drop, causing wood floors to dry out. When that happens, the wood shrinks and small gaps form between the floorboards. There are a number of ways to mitigate this problem and help to preserve the look of your flooring while adding to it’s longevity.
Use the Right Flooring
Engineered flooring is less likely to shrink, but even these floors are restricted to RH’s of around 35-55%. If the RH is outside levels recommended by the manufacturer, the warranties are void. Be sure to check the manufacturer’s instructions and maintain a RH within the warranty stipulations.
Using narrow flooring boards works to minimize gaps and being mindful of the wood you use can help as some wood species are more dimensionally stable. Flooring that is quartersawn will also shrink less than flatsawn lumber.
Controlling Ambient Moisture
Once the flooring is in, the occupant can control the home’s moisture to reduce gaps. In order to reduce gaps in winter and buckling in the summer, we need to reduce the range of RH levels i.e. keep the indoor moisture levels constant. For example, air at 30 degrees Fahrenheit and 50 percent RH when warmed to 70 degrees will be at 10 percent RH.
You can control moisture levels by reducing the ventilation. When cold winter air is vented into the house and warmed, the RH drops significantly. By reducing ventilation (the air changes per hour or ACH) through sealing leaks, you can keep the moisture levels up in your home.
You can add moisture to the home with humidifiers. The colder the outside air that you are bringing into the house, the more moisture you need to add. Normal household activities and occupants do add moisture to the home, but you will need to augment those in the winter.
When adding water, be sure to measure your RH regularly. Too much moisture can result in mold which is damaging to buildings and occupants.