When was the last time you saw a chimney on a house that was made of real brick, stone or masonry? It seems these days a lot of chimneys are made of wood framing and are clad with EIFS or stucco or some form of siding. Usually, the fireplace itself is a prefabricated metal box that connects to sections of insulated pipe that go up through wood-framed chimney enclosure. If EIFS is the dominant cladding on a house, chances are good that the chimney enclosure will be EIFS, too. Here are some guidelines on how to do EIFS as a cladding on chimneys.
First, understand that EIFS is combustible and can catch on fire if it gets hot enough. Wood studs, wood sheathing and many common types of siding are also combustible. Obviously, this heat needs to be kept away from the EIFS. With EIFS that uses EPS as the foam insulation, the melting point of the EPS is low enough that even though it may not burn, it might melt and flow, ruining the EIFS. The point is to make sure that the type of fireplace and flue is suitable for use in proximity to EIFS. The problem usually isn't the firebox or the chimney flue, as these are rated so that they can be used within a wood framed enclosure with minimal clearances between the flue/firebox, and the wood framing/sheathing. However, at the top of the chimney, a different issue surfaces.