EIFS – A few reminders

There is a lot of information, tips and tricks available for Exterior Insulation Finish Systems. There are also quite a few of these tidbits that are worth repeating.

Mixing manufacturers

EIFS is composed of different materials that are sold by manufacturers and installed as a complete system onsite. This might present a tempting situation for some installers or designers, who feel they might be able to mix and match components from different manufacturers to save costs or develop what they think will be a better system. However, this is one of the worst things you can do with EIFS. Not only have the manufacturer’s systems been designed, developed and tested to work together but mixing components can void each manufacturer’s warranty. When one needs to figure out who made the EIFS, it’s nearly impossible to trace it back to anyone. Accountability and responsibility, instead of being the problem of the manufacturer, become placed solely on whoever installed such a system.

Foam shapes

When installing foam shapes, there are a few factors to take into consideration. The first is the same as above, no mixing and matching. The foam shapes and EIFS materials used with them should come from the same manufacturer.

These foam shapes can be either foam that is attached to the EIFS and coated with EIFS materials, or precut and coated offsite and then adhered to the EIFS wall’s base coat.

When bonding the foam shapes to the base coat, thick ribbons of adhesive can be used to create drainage between the two elements.


EIFS were designed and developed to be used as exterior wall insulation, not for other uses. This fact does not stop EIFS materials from being installed other ways, even though it could still run the risk of voiding the warranty. When EIFS is used as a soffit, it can lead to a couple of problems. The first of these problems is the lack of support for the EIFS, which can catch the wind easily and blow upwards, cracking the lamina and weakening the structure. The second and most important problem is that the soffit will be at risk if there is a fire, because the flames will plume upward if a fire breaks out nearby. The EIFS soffit is largely unsupported and if it catches fire the expanded polystyrene foam will melt, and the soffit will fall to the ground.

Preventing grunge from getting on vulnerable areas

EIFS around windows or walkways might be vulnerable to absorbing dirt. This is compounded by the fact that the finish of the EIFS will soften when affected by moisture, allowing dirt to embed a lot easier. This embedded dirt problem can be avoided by applying a clear acrylic coating around any small, vulnerable areas of the EIFS.

Using EPS creatively

Inserting sealant backer rods into joints around foam shapes can be cumbersome and difficult. EPS can be used as a substitute for the sealant backer rod, and is easier to shape via cutting and contouring into the joint, used as a spacer between foam shapes. This method can also provide the joint with some extra insulation.

EIFS indoors

EIFS is designed for outdoor use only. Using it to decorate walls, ceilings or for any other indoor use is not something that should ever be attempted. For one, it will void the warranty, leading to the same accountability issues as described prior.

EIFS is okay to use on non-combustible walls even though it’s not non-combustible. This is only because the EIFS is separated from the inside of a house by at least a 15-minute thermal barrier, as required by building codes. On the inside of a wall, this is not the case and the EIFS will be the first thing to melt or burn. If the look of EIFS is strongly desired on the inside of a home or building, the EIFS finish is okay to use to paint surfaces indoors, although there are already many products available for this purpose.

Extreme drainage

EIFS with drainage has been tested and developed to drain water adequately and safely out of an EIFS wall. This is done one of several possible ways, either using plastic mesh spacers, cutting grooves into the back of the foam or by using thicker beads of adhesive which create “channels” behind the EIFS for drainage. Some might think this leaves room for making the drainage cavities even bigger.

With drainage EIFS, bigger isn’t always better. Extra-large cavities can lessen the insulating properties of the EIFS, and drainage cavities no larger than 1/8 of an inch are optimal for both drainage purposes and maintaining the insulating abilities of the EIFS.

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