Roof blisters are a common problem exhibited by different types of flat commercial roofs. They are difficult to avoid, even for the most experienced commercial roof company, and are seen as a somewhat of normal occurrence. Yet the real question is usually what to do about them. Some require repair, but even the best of commercial roof companies may recommend leaving others alone. These pros whose business it is to service and repair commercial roofs emphasize that the proper decision depends upon the circumstances.
What Are Roof Blisters?
Roof blisters are pockets of space that rise up under the surface of membrane roofs where the top layer has separated from the insulating layers underneath. Most flat membrane roofs experience a certain amount of these "bubbles" to some extent. Many of resolve themselves over time. Yet some will continue to enlarge and even break open, leaving unprotected areas on the roof. These areas become the beginning of leaks and other types of serious damage.
How Do Roof Blisters Happen?
There are a number of causes of roof blisters. These raised pockets form when layers of roofing materials that are used for flat, membrane type roofs do not adhere to each other well enough, and begin to separate. This may simply be because of: undetected, uneven application of adhesives between layers; poor quality roofing materials; or due to unavoidable contraction and expansion of roofing materials from temperature fluctuations. In situations where these pockets are small, dissipation often occurs its own after repeated expansion and contraction. When the bulges do not go away on their own, or if they continue to separate and get bigger, they may need to be repaired by a company that offers services for commercial roofs, to prevent bursting, as well as the continued damage that can occur to a roof afterwards.
Repairing Roof Blisters
Different membrane systems require different types of repairs for these blisters. Deciding whether or not to actually make any kind of repair is an important consideration as well, and one that should be made by roofing experts experienced in the repair of commercial roofs. If the blister is small in size, and not water-filled, or if it does not appear to be creating a weakness in the roofing material itself, leaving it alone is often the best decision. These spots can also be reinforced in an attempt at preventing them from breaking open. Leaving the roofing membrane intact is always the preferred choice if the area is not at risk for leaks, and cutting the blister out and patching it is not absolutely necessary. Yet leaving a blister alone and not repairing it can also invite problems such as bursting, leaking seams in the membrane, and enlarging areas of separation that will eventually cause leaks, etc.
When a repair is necessary, professional commercial roof services companies indicate that the technique to use depends upon the type of membrane roof that has been installed; however, the basic techniques are the same. A repair first involves opening the blister and inspecting the extent of damage underneath, then removing any damaged materials. If the blister is simply filled with air, the blistered membrane is cut away until there is good adhesion, then repaired with an overlaying patch. If the blister is filled with water, the repair is more extensive, and requires cutting out not only the blistered membrane, but any layers underneath that are wet and damaged. All of those layers must then be patched individually before applying a top patch over the entire area. Wet pockets involve a much larger, more in-depth repair.
While roof blisters are frequently seen as unavoidable nuisances on many flat commercial roofs, they do require careful consideration and monitoring to prevent them from becoming bigger problems. Determining whether a repair should be made is something that should be decided on with the help of an experienced commercial roof company skilled in making these delicate types of repairs. In either case, the wrong decision could end up requiring a whole new roof in the long run!