The Finish Line: Eco-Friendliness of EIFS
May 1, 2010
If you spend any time working with specifiers, end-users, designers and contractors who are involved with EIFS, you’ll find out right away that the environmental friendliness (“eco-friendliness”) of EIFS is a hot topic. They want to know how EIFS fares as it relates to the environment, and there are numerous incentives to using green materials. It’s not just a hot topic for EIFS-almost anyone supplying construction materials gets questions constantly about how a given material relates to ecological issues.
These ecological issues span a wide range of characteristics of a product itself and its use. This includes the raw material (their acquisition and manufacture), the energy usage in place, and what happens to them down the road. For example, some materials are “sustainable,” which means in human lifespan terms, that the materials can be regenerated. Trees grow fast and thus are sustainable; oil takes eons to be created, and thus is not. Similarly, some materials can be recycled (used again) as is, while some can be remanufactured, while still others are useless and have no final place of rest other than a landfill.
EIFS is a multi-component system made from a range of natural and manmade materials. It is one of those that is exceptionally eco-friendly in some ways. This month’s column will give some insight into how EIFS fares as an eco-friendly material.
In terms of energy efficiency, it’s no secret that EIFS is excellent. The external location of the insulation gives the best insulation efficiency for a wall. But that’s not the whole story. So, let’s take EIFS apart and see what is involved with the production, in-place use, and disposal/reuse of the system.
The production of EIFS materials, and the curing of EIFS adhesive and finishes on the wall, is based on chemistry that uses water as the solvent. Unlike other more sophisticated chemistries that use non-water solvents (such as toluene), production of EIFS materials does not create bad emissions into the air. There is also little waste and what goes down the drainage when cleaning the production blending equipment can usually be neutralized safely, although in some areas, like California, extra steps must be taken.
CRADLE TO GRAVE
In some countries, the eco-friendliness of products is looked at in the broadest sense. It’s not just how energy efficient it is but also such aspects as making, transporting, installing, using, and disposing of the worn-out product. For example, there’s not much in EIFS that “wears out.” EIFS is a passive product (no moving parts), so it doesn’t wear out in the normal sense (like a car does).
But what do you do with an EIFS-clad building that is being torn-down? What do you do with the EIFS? It’s light, but bulky. Surely, if the building has a steel frame, the beams and columns can be melted down and reused. But what to do with this EIFS?
EPS-LOTS OF ECO-FRIENDLINESS
The cradle-to-grave approach goes further than just burying materials from demolition. Think of this: What is the EPS foam (the bulkiest part of EIFS) made of? Styrene. Styrene is plastic and thus combustible-i.e., it has energy stored in its structure, like a fireplace log. You can burn styrene in an incinerator and make electricity. That’s cool (or hot). Modern incinerators also scrub the exhaust gases of bad stuff, so the environment is not polluted.
EPS can be ground-up and re-used to make new EPS by mixing with new material and remolding it. The used material is called regrind, and lowers the cost of the EPS. Using regrind changes the properties of EPS somewhat. For certain applications, such as EPS boards used in places where it is not stressed, it works just fine. In EIFS applications, the EIFS producers specify 100 percent virgin EPS beads, but in some countries a small amount of regrind is acceptable.
EPS can be ground up in pieces the size of a pencil’s eraser and mixed with soil to make the soil more bulky and provide for aeration and drainage.
One issue that sometimes comes up with EPS is when it’s being installed or ripped off a building. For instance, when using a router to make aesthetic reveals, zillions of tiny EPS beads get released into the air. These are so light that the wind can take them great distances where they end up on streets, cars, lawns, and so on, raising the ire of residents. Luckily, vacuum attachments are available for routers that suck up the beads as they are produced, getting rid of the problem to a large extent.
Acrylics are a type of plastic made of a synthetic polymer of methyl methacrylate. Plexiglas and most house paints use acrylics, and acrylics are an exceptional versatile material. Acrylics come in solid form (sheets, such as for windows), liquid resins (paints and adhesives) and powder versions of reins. Acrylics are made from petroleum and thus are non-renewable in the human lifespan-unlike trees.
Many EIFS coatings use acrylics, as they have good adhesive characteristics and are resistant to sunlight. The acrylics in EIFS coatings are bound into the coating (with cement, fillers, aggregates and other materials) and are not retrievable for re-use. Thus the parts of an EIFS that has acrylics in it, end up in the landfill.
INCREASING ENERGY EFFICIENCY
In some countries, with much higher energy costs than North America, existing EIFS jobs simply do not have enough insulation thickness to meet the latest energy efficiency standards. One nice feature about EIFS is that you can bond a new layer of EIFS on top of an old one. You do not need to strip off the existing lamina-simply bond the new foam layer to it using a special adhesive. The building’s appearance changes little, the insulation level of the wall goes up, and it’s all done from the outside-it doesn’t bother an existing building’s occupants (see drawing).
THE EIFS LAMINA
When recycling EPS, the EIFS lamina needs to be removed. Often it can be peeled off of the foam. It has no recycling value as it is a thin, laminated layer, and gets mangled by being stripped off. Also, when peeling off the lamina, the outside surface of the EPS foam gets chewed up, making the EPS unfeasible to be used again in EIFS.
Portland cement is used in many EIFS adhesives. Although small in the amount used compared to bulk uses of Portland cement, such as in roads and dams and building foundations, it’s still there. To give you an idea of how much Portland cement is used, concrete, which uses Portland cement, is the most used manmade material in the world.
An alternate to Portland cement-based EIFS adhesives is to use cementless EIFS adhesives. These are more expensive but do exist now.
THE FUTURE OF A GREENER EIFS?
In Europe and Asia, there are a large number of small EIFS producers. These producers serve small regions. This reduces shipping costs due to short transportation distances and less fuel used. In North America, there are a small number of large producers with large factories scattered across a vast land area. Thus, in North America, shipping costs and resultant transportation fuel costs can be high for producers who have to ship coast-to-coast.
The use of aggregates other than sand and marble to create the texture in EIFS finishes is getting more attention. In particular, the use of manmade “waste” byproducts from industrial processes is possible, such as combustion byproducts from the production of energy (such as slag and ash). Even car tires, which are notoriously hard to dispose of, can be ground-up and used to make small chips to act as the aggregates for textured coating.
MAINTENANCE AND LIFE SPAN
The oldest EIFS jobs I’ve seen are in Europe. They date back to World War II and are doing fine. The typical maintenance involves occasional painting to freshen the appearance and the replacement of sealant in expansion joints. How long will EIFS last? We know at least 60 years, based on the oldest projects in existence, and these were made using resin technology that is nowhere near as advanced as what is used now.
In Europe, buildings are generally more heavily constructed, using massive masonry and concrete walls that literally can last for centuries. In North America, however, the trend is to view buildings as investments that are expected to be viable for a few decades, and are constructed using lighter wall systems. Hence the building itself may need a major refit before passive systems, like EIFS, wear out. The cost to refit an existing building-with active systems like electrical, plumbing and HVAC-could make maintaining the building unwise. Thus, EIFS fits the bill nicely from a financial standpoint. W&C