Today, men are able to build just about anything. There are many modern majestic structures throughout the world. Once a structure has been finished, it is on the the next project. Our cities continue to grow larger, and the building grow older. Many older buildings have been given historic status. They are provided with a sprucing up that holds true to their architectural standards, requiring them to maintain the good old wooden windows or they can be replaced with brand new ones. Many builders add secondary glazing as an attempt to increase the effectiveness of the windows, but there is the potential for problems with secondary glazing and condensation.
Secondary glazing is simply an extra glazing panel that is placed on the inside of an already existing single glazed window. It is usually a single glazed piece of glass, but can sometimes be shrink wrap or a plastic film. It is usually surrounded by a metal frame that incorporates a gasket or membrane in order to create an air space that is sealed between the new glaze and the old.
While some people are unfamiliar with secondary glazing, almost everyone understands condensation and how it generally occurs. For windows, since they are glass, it typically means that the exterior and interior temperatures are differing enough to cool the moisture that is in the air by the glass causing it to condensate onto the surface of the glass.
When it comes to wood windows, humidity and moisture are one of the things to avoid. They can cause warping and rotting, not to mention mold. Often times, problems are not identified until it is too late and the window has to be completely replaced.
Unlike double glazing, which is typically vacuum sealed in a moisture controlled factory, secondary glazing traps ordinary, moisture filled air, between it and the single glazed window. A drafty window can also allow moisture from the outside in. Given the right condition, that moisture will condensate between the glass and settle at the bottom of the window, increasing the chances of rot. This will also increase the humidity level between the two panes of glass, which will effect any wood exposed inside the seal.
The metal frame of the glazing panel also can be a culprit. Just like on glass, metal transfers temperature to the air and is likely to have moisture on it as well. While the moisture on the glass is easy to see, what is on the metal, especially between the panes, is much more difficult.
Wooden windows that are failing because of moisture should be immediately replaced. It is important to consider all options when deciding how to weatherize windows, as replacement is costly and laborious. There are positives and negatives associated with all options, but secondary glazing and condensation is an important problem to remember.