The Finish Line: Right Solutions for the Right Problems
October 24, 2011
EIFS is like any other building material in the sense that it is well-suited for some uses and not for others. This column is a compilation of my thoughts about where EIFS works well and where it does not, including some unusual specialty uses.
Local Aesthetic OrdinancesIn some towns, local laws only permit the use of certain materials for exterior claddings. This is especially true in historic districts. Local laws may require that a certain percentage of the cladding on the street side be a material like brick. In some cases, materials like EIFS and stucco are not allowed. The local building department, contractors, developers and architects can advise if such laws are in effect and how you might go about getting a variance (if that’s a possibility).
Dirty EnvironmentsPlaces where there is a lot of soot, smoke or exhaust fumes can pose a problem with EIFS. The dirt can get embedded in the EIFS finish and very difficult to remove. Examples of this type of situation include bus stops and areas with a lot of vehicle traffic. One way to reduce this problem is to coat the EIFS finish with a sealer to make it shed the dirt more easily. In cases where the dirt is already there, the EIFS finish can be painted but will also need to be carefully cleaned first. The use of hard cleaners can ruin the EIFS finish. There are specialty cleaners commercially available for use with EIFS and some of them are advertised in this magazine.
ICFsEIFS can be used as the finish for insulated concrete forms. Whether or not a specific EIFS coating system can be used on a given ICF (there are a number of designs) depends on whether they work together. Some EIFS producers endorse the use of only certain products with ICFs; check with them for details. There are several aspects of ICFs that are different than normal EIFS.
ICF foam may be of a density of grade that is incompatible with EIFS. The forms need to fit tightly together-without gaps-to avoid cracking of the EIFS coating.
The forms need to stand out in the weather for weeks while the concrete cures. This will degrade the surface of the EPS form. The form will need to be sanded so the EIFS coatings will adhere. The whole wall will need to be sanded.
Adding Extra StoriesThe exceptionally light weight of EIFS can make a difference when adding extra floors above the existing roof. This can help get around the problem of having to reinforce the existing building structural systems. This can save a lot of time and money, and get around the problem of disruption of on-going use of the building.
Blow-Off PanelsAn unusual application that EIFS is well-suited for is in walls that are designed to release from the building frame at a predetermined force. Usually, these are metal stud panels with EIFS cladding. Examples of this include buildings used for industrial processes that may explode and those where the base is subject to flooding. The latter allows the walls to come loose, thereby letting the water surge under the building. The building I am sitting in now is on a beach where hurricanes have landed. The building is on stilts and a parking garage on the ground floor. It has these types of panels.
EarthquakesThe light weight and flexibility of EIFS can be an advantage in areas where buildings might rock and roll. The “give” of an EIFS structure allows it to not crack and fall off. The light weight of EIFS-especially on upper stories-helps limit the amount of weight that is being thrown around by the movement of the building.
SecurityIf physical security of a wall is important, such as in the construction of a bank building, EIFS is not the answer. The light weight nature of the EIFS coatings provides virtually no resistance to penetration-you can ram a screwdriver through it. The penetration resistance must come from a robust substrate such as concrete or block.
One example of this came in an odd request I once was asked about using a metal stud and gypsum board wall with EIFS as the cladding for the exterior walls of a prison.
Agressive EnvironmentsIf the air around an EIFS-clad building is full of chemicals, EIFS is not a good solution. The styrene foam core of EIFS is not highly resistant to attack by solvents. Thus, the use of EIFS around refineries and chemical plants is a bad idea.
People sometimes ask me if EIFS will work in extreme cold or hot climates. The answer is that this has been done lots of times. The key is to design the EIFS properly. Probably the most aggressive common environment is humid, hot, salty seaside areas. Even then, EIFS can hold up well. The key is to do routine maintenance, including surveying the face to look for leaks and cracks.