Folks are constantly asking if we can apply EonCoat to foam (expanded polystyrene foam insulation). While EonCoat will not bond chemically to polymers as it does to cement, steel, and wood it will bond mechanically the way other coatings do to surfaces that are rough.
The short answer is that you can apply EonCoat to EPS and many folks do:
Doing so produces a rock-hard shell that offers zero flame spread and provides a significant heat transfer barrier as well that keeps the foam from melting on the other side of the coating for quite some time when exposed to flame.
The more complicated answer comes when we’re asked if this makes a fireproof barrier:
While EonCoat is completely fireproof (it will not burn) and provides a flame-proof barrier – no coating prevents heat transfer (although they do slow it down). If the flame is hot enough eventually enough heat will pass through to cause the EPS to melt. This same principle applies to other substrates (like wood) that do not melt but will self-ignite when the heat transfer is sufficient to raise the temperature to the temperature at which that material ignites on its own without the need for flame spread.
Heat transfer is a function of the outside temperature, coefficient of heat transfer of the barrier material (EonCoat is .2 watts/Meter-Kelvin), and length (or in this case thickness of the coating). Increasing the thickness of the coating has a linear impact on the time it takes for the substrate on the other side of the barrier to either melt or self-ignite.
So if you build houses out of Structural Insulated Panels that use EPS applying the proper thickness of EonCoat can give you the fire resistance you need to meet building codes as well as give your customer a hard shell wall and a safer place to live. It will also provide a completely Zero Off-Gas barrier which greatly increases safety. No other coating is completely non-toxic the way EonCoat is.
An added benefit is that the EonCoat barrier also eliminates mold growth.