Wood flooring reacts to the environment it is in. Wood gains or loses moisture and correspondingly gets bigger or smaller based on the moisture content and temperature of its surroundings. Keeping your range near 70 to 75 degrees Fahrenheit (F) and about 40-60 percent relative humidity (RH) can do wonders for your wood floor.
Wood floors react to an indoor environment in a predictable way because it’s relationship with temperature and humidity. A more stable environment results in a more stable floor. Wood species, board width, and construction of your planks are factors that determine environmental requirements. Engineered planks will not fluctuate nearly as much as solid wood planks.
One solution to dry or humid houses is to add humidity controls. Humidifiers are added for the heating season to keep things from getting too dry. Dehumidifiers are added or air conditioners are turned down to deal with summer moisture. It is crucial to not over-humidify to the point that condensation on windows or other building surfaces occur.
Air conditioners can help control summer humidity levels but need to consistently run to be effective. AC units typically do not dehumidify much in the morning or during cooler spring and fall seasons when moisture loads can still be high. In many cases a stand-alone or whole-house dehumidifier is necessary, especially with wider flooring in more humid climates. In this way humidity levels are controlled independent of temperatures.
Outside air is not the friend of wood flooring. Winter ventilation tends to dry flooring; summer ventilation tends to add moisture to flooring. Beyond what is necessary for human health and safety, more is not better. An effective step in reducing floor issues is to reduce ventilation and air infiltration as much as possible.
The next step is to get the environment across the floor as consistent as possible. Try to eliminate cold spots resulting from AC systems, ducts and registers, and exterior wall drafts. Eliminate hot spots at windows and near heating systems, ducts and registers.
Another step is to get the environment on both sides of the flooring (above the floor, below the floor) as similar as possible. In under-floor spaces such as crawlspaces, thermal, air and moisture flows need to be addressed. Using insulation incorporating an air and moisture barrier can accomplish this. Separate thermal, air and moisture barriers can also be combined to do the job.
A consistent, stable environment will result in a more stable, consistent wood floor. With today’s high consumer expectations and flooring preferences, consistent, stable environments are necessary for a successful wood floor installation. The good news is that creating those environments is quite possible and cost effective. The bad news is that it takes many other building trades to help make it happen.