Wet Weather
TIMBER FLOORS IN WET TIMES
Depending on where you live in Australia your climate may be one where you get periods of wet and dry, yet in other parts of the country the extended periods of wet weather have not been seen in many years. When the wet weather has been more intense than previous years we have seen expansion pressure in floors take its toll. Floors that may have performed well over the past two to four years may now peaking (raised board edges), tenting or buckling (boards lifting).
At these times of the year gaps close in floors and floors that showed no gaps become even tighter as expansion joints close. When I take a casual look at the humidity meter and see that it is 78% and think to myself, it’s been up at these levels on and off for quite some weeks, my floors are going to be expanding.
So let’s take a look at the conditions within our dwelling to understand what is happening with our floors.
RELATIVE HUMIDITY, MOISTURE CONTENT AND EXPANSION
The relative humidity is a measure of how moist the air is and the higher the percentage value, the more moist the air. When the relative humidity is high, moisture in the air is absorbed into the timber flooring causing the moisture content of the flooring to increase. An increase in timber flooring moisture content is accompanied by swelling. This is shown in the adjacent diagram.
Although both temperature and humidity alter throughout the day and night, a floor’s response is usually relatively slow and we often only see minor changes from month to month. However during prolonged wet periods things can be different.
The moisture in the air is absorbed into our timber floors, gaps close and the floor can tighten considerably.
Many of our higher density hardwoods are slow to take up moisture, but if wet, high humidity conditions remain long enough they are certain to absorb moisture and expand. However, just as they were slow to take up moisture they are slow to release moisture back to the air. Even when less rain is experienced it will take some time for moisture contents to return to normal levels. In some parts of the country this effect may linger for some months until the drier time of the year.