The concept of insulating a building's wall by putting the insulation on the outside face of the wall goes back hundreds of years. This manner of insulating, as opposed to putting it in a wall cavity, can be seen many places around the world using, for instance, a form of stucco over straw. The technical merits of doing insulation this way, however, were not well known in the architectural community until the 18th century, when the science of the physics of heat and moisture flow became better understood. Basic EIFS-type technology, by the way, is used in many other applications, including insulating liquid storage tanks by spraying insulation onto the tank shell, and for various techy applications, such as the ceramic tiles on the underside of the space shuttle.

The main problem with developing a modern EIFS was one of material technology, and was only really solved around the middle of the 20th century via the development of several types of plastics. In particular, plastic resins for use in making adhesives and paints, and the ability to reduce the density of plastic to form rigid insulation boards, were developed before, during and after World War II. The basic technical material problem was one of how to protect a sunlight-sensitive foam plastic insulation, like EPS, from the weather. The other major issue was the durability of the resin used as the exterior surface; how would they bear up to the weather? Some type of new covering was needed. Preferably it could be a light, trowel-applied material. Stucco could be?and still is?used, but a lighter system that could be fully bonded to a solid wall would be nice.

Picking up the pieces

One way to solve this matter was to glue lightweight insulation onto the existing heavy masonry walls and then put one of the new thin resinous coatings over it.

This approach had many pluses: It got rid of what was a war-ravaged fa?e, it allowed the work to occur while the building's interior was being rebuilt, it saves energy, and it solved the age-old problem of condensation on the inside face of exterior walls.

Most of the walls in these buildings were some sort of heavy concrete or masonry or tile, with a stucco or stone-outside face and a plaster interior finish. Such walls are essentially uninsulated, and "sweat" in the winter due to the warm interior air coming into contact with the cold plaster. This is not only annoying (dripping, etc.) but also unhealthy, as it can cause mildew.

With a tradition of plastering skills to do the work and a lots of reasons to do it, this modern type of EIFS, what we call a barrier EIFS, became very popular. EIFS of this type was first successfully introduced to the North America in the 1960s, and the rest is history.

It is interesting to note that numerous unsuccessful attempts were made prior to the mid-'60s to introduce EIFS into the North American market. Some of these efforts were made by major American and European companies. The reason they did not succeed was primarily due to market development problems or oddball EIFS design that were hard to install. It took an oil embargo in the '70s to spark interest in insulation and an ambitious young company to break the market open.

There are some important aspects of the European way of using EIFS that bear directly on the EIFS scene in the USA. These aspects are cultural and architectural.

Solid and stable

There is another aspect that is important in the concepts that were part of the design thinking that went into EIFS. One of the key issues is that a heavy wall structure that has a barrier-type cladding system need not be 100-percent watertight to not have water problems. The reason is simple: the supporting wall is so thick and heavy that water doesn't affect it much, and water won't make it through.

A myriad of types of EIFS exist around the world, yet strangely only two basic EPS-based types are popular in North America: barrier and drainage types. European EIFS producers I've spoken with find our drainage EIFS to be a bit odd. They don't understand why we need drainage. They feel the same about other aspects of our culture, so let's just agree that we build our buildings differently. In North America, where most EIFS is used over stud-cavity walls, the water situation is different due to the nature of the supporting wall. Hence the trend toward the use of drainage-type EIFS in North America.

You might be curious that in many places worldwide where EIFS-like products are used, the exterior surface is some sort of plaster over some type of noncombustible insulation. This allows the EIFS to meet more stringent fire codes. There are also externally insulated EIFS-like claddings that have some sort of membrane (stucco or cement panels) suspended, in a rain screen manner in front of a layer of insulation. It's not unlike some of the EIFS designs being used right now in Canada.

Where will the history of EIFS take us? My guess is that drainage systems will become more popular and more refined. It'll take a decade or more for all this to shake out.

Meanwhile a basic understanding of how we got where we are today makes interesting conversation when dealing with customers in the construction industry.