In this article we’ll look at how air pressure can effect your wood floor. We’ll go into some detail and explain how several aspects such as air pressure, relative humidity, dew points and air temperature are all connected and how they can combine to effect any wood flooring.
There’s a lot of talk in the field of wood flooring that the only issue to watch out for regarding your flooring is air humidity as this has a direct impact on the expansion and contraction rate of a wood floor. However, there is also something that has a direct impact on the air humidity, air pressure. Now what we will look at here is not a completely cast iron reason for increases or decreases of air humidity in a property as other factors can effect air humidity levels, such as, leaks, floods, heavy rainfall etc.
Before we look at how air pressure interacts with humidity levels and it’s effects on a wood floor, we need to look at what changes air pressure. What is the driving force to send air pressure up or down in a home? Well there are several reasons for this and the first we’ll look at is temperature. A simple equation we should bare in mind is cold air drops and hot air rises. Think of the morning mist. The result of a cold night, the air pressure has dropped as the moisture in the air becomes more dense and settles or condenses on ground surfaces in the form of dew (the temperature of the air at this point is called the dew point). Then with the morning comes the heat from day light (the sun). As the heat warms the ground and the atmosphere, the air pressure rises as the moisture molecules in the air expand and begin to float upwards (mist). Gradually as the day carries through, the mist will vaporise or not depending on the weather conditions for that day.
The dew point is relative to the air humidity. In this chart we see that if the air humidity is at 50% and the temperature is at an ambient 20C, the dew point will be around 9C. So, to put that into understandable language, if you have an air humidity of 50%, the temperature in your property will have to drop to 9C before it hits the dew point and water starts to settle on surfaces. In other words the air pressure will drop to ground at 9C. An indication of low pressure. You can see now the fine interaction of water and temperature and how each property and area can be effected differently.
Air pressure can also be affected by the distance from sea level in height a particular area is. For instance air pressure would be naturally lower the higher from sea level a property is. Here we are looking at an average in home environment. So if you live at the summit of a mountain, the basic concepts we are discussing here may not apply fully.
So to summarise this point, air pressure is often directly associated with temperature and air humidity density.
Now what else can effect air pressure. Ventilation or sealed units. Air pressure can be increased or decreased by suction and also by blocking out outside atmospheric conditions. This is often what we are attempting to do in our homes. Block out the elements as they say, and we do it successfully and often without properly realising what we are doing. We are bypassing nature to provide a more consistent environment for our family.
Now if ventilation in a property isn’t consistent. That is to say an equal amount of air into a property as out, an imbalance of air pressure will occur. To give an example, if there was an open external door in a house and a small open external window on the other side of the house, this would create a vacuum effect and alter the air pressure. If a property is completely sealed, the only thing that would alter the air pressure is the temperature and the occasional opening and closing door or window. This isn’t necessarily a bad thing but is worth understanding.
In modern day living we have increased technologies to trap heat into our properties i.e. Loft insulation, double glazing, super dooper door seals etc. However, this has been done to the sacrifice of air circulation. Therefore, relying on temperature to regulate the air pressure. Often in modern living we get this wrong. We regularly dry our clothes indoors, cook, bathe etc. The higher we raise the relative air humidity in our houses the higher we raise the dew point. For instance, looking at the graph above, if we increase the relative humidity of the air to 70% at an air temperature of 20C, the dew point raises to 15C. This is the point were moisture will start to condense and condensation will occur. This can have a dramatic effect on a wood floor.
Condensation will appear on cold surfaces. As generally a wood floor can get cold, it can be the first thing to show condensation. This can also happen with ceramic tiles, windows etc. The problem with condensation with regards a wood floor is the obvious potential for the wood to soak this condensation in and expand. This is dependent on the type of finish applied to the wood, for example a lacquered finish will help against moisture absorption whereas an oiled finish will allow moisture absorption easier. It is also dependant on the amount of condensation build up. A build up of condensation isn’t necessarily a problem to the floor but if there are signs of this, it is an indication that the dew point has been reached.
In situation where there has been a leak in a property, condensation is a common issue.
Air pressure has a direct link to air temperature and air humidity. If any of these are sent out of kilter, they can have a huge effect on a wood floor. It’s worth mentioning that a wood floor is exceptionally good at gaining an equilibrium with it’s environment. A lot better than humans most of the time. However, for a long lasting wood floor, stability in the internal climate of your property is key. Knowing how to stabilise it after a rapid change is also an important factor. Wood floors can adapt well to slow changes and can even enjoy high humidity levels and low humidity levels, but one thing that will throw a wood floor into a failed state is rapid atmospheric changes all associated with air temperature and air humidity (together air pressure).
© Copyright 2013 Wes, All rights Reserved. Written For: Fitmywoodfloor