Cavity Wall Insulation Problems
Avoiding Cavity Wall Insulation Problems
The potential of cavity wall insulation problems is not always well understood, even by contractors. For one thing, the practice for many years was confined to brick structures, where insulation is applied to the gap separating the two layers of brick. The gap, or cavity, simply came about as a normal part of the construction process. In most instances the cavity caused no problem and the air in it could for that matter be considered to have some insulating properties. In some structures however, a cavity can cause problems, and filling it with insulation often solves those problems. In general, cavity wall insulation problems have been few and far between in brick structures, and many older buildings have had this type of insulation installed in recent years.
Inside Problems - There are instances where dampness can be a problem. This is usually not the fault of the insulation itself, but rather due to moisture being allowed to accumulate, due to a crack or other opening, where the insulation is present. Moisture often accumulates if cavity wall insulation has been installed unevenly, leaving empty spaces. In some cases, moisture is already present within the cavity before the insulation is installed, and adding insulation normally does not eliminate existing moisture. A moisture problem in the cavity then becomes a cavity insulation problem.
Outside Problems - Other cavity insulation problems that can occur are more cosmetic in nature, since the insulation is applied by drilling holes in the exterior wall and plugging the holes up once the insulation is in place. The plugs cannot always be disguised by simply touching them up, and often the entire wall has to be refinished. Or, the plugs may be successfully touched up, but will begin to reappear within a few short years.
Wooden Structures Have Their Own Problems - For a brick structure, installing cavity wall insulation is generally inexpensive. For a wooden structure however, it can be quite expensive, as the many more holes will have to be drilled, and usually much more insulation will have to be put in place. The end result however should be a house that is warmer in the winter and cooler in the summer, and a house that is in many respects a quieter one as well, at least as far as outside noises are concerned.
More cavity wall insulation problems are likely to be encountered in wooden structures, primarily due to voids, or empty spaces, that are left once the insulation has been put in. Since the insulation is blown in after the interior and exterior walls are already up, it's not always possible to tell whether a void exists or not. If it is a newer structure, settling can sometimes cause a void, where none existed when the insulation was first installed. The presence of one or more voids can sometimes nullify, at least to an extent, the benefits cavity insulation otherwise provides.
Installing Insulation Up Front Is Best - The best approach naturally is to have insulation installed when a house is being built, and this is generally the practice today. Insulation, when installed up front, will usually pay for itself during the first few years the home is in use. Many older homes did not have this done, sometimes with the idea of saving a little money. For an older wooden home, cavity insulation installation can be quite expensive, and is something that usually has to be done by a professional if it is to be done right. Unfortunately, when it comes to insulation, installing just a little does little good, and installing it completely but imperfectly, leaving many gaps and voids, is not much better, and can be a waste of money.