What is the R-value of expanded polystyrene insulation?

The R-value of expanded polystyrene insulation ranges from 3.6 to 4.2 per inch, with an average R_value of 3.85 per inch.

What is the difference between extruded and expanded polystyrene insulation?

Extruded polystyrene is denser, generally has better thermal performance and mechanical resistance compared to expanded polystyrene. It's better suited for areas that face extreme weather conditions such as heat, cold, and moisture. Expanded polystyrene is very lightweight and easy to work with, although it is more susceptible to fire.

How long does polystyrene take to decompose?

Polystyrene is considered non-biodegradable, but the product is 100% recyclable.

Does expanded polystyrene burn?

Expanded polystyrene contains an added flame retardant that increases its fire resistance, but the material is combustible and can burn under certain conditions.

Is expanded polystyrene waterproof?

Expanded polystyrene is a closed-cell foam, but it is not entirely waterproof. Adding a vapor barrier is recommended when insulating damp places.

Is polystyrene a good insulator?

Polystyrene is a good insulator because it contains many small air bubbles that do not allow heat to pass through it.

Is expanded polystyrene insulation environmentally friendly?

Like many plastic products, expanded polystyrene is considered non-biodegradable. It is an oil-based product, but there is very little waste produced during the manufacturing process. It's also relatively easy to recycle at the end of its life.

Is expanded polystyrene insulation safe?

Expanded polystyrene is considered chemically inert, non-toxic, and safe to work with.

In-Depth Product Guide

Expanded Polystyrene Board Insulation

FAQs

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Expanded polystyrene (EPS) is a rigid polystyrene foam board with a more open structure that is more permeable to humidity than extruded polystyrene. If you break a piece of EPS, you see its characteristic structure of little beads of foam all stuck together.

For insulation in contact with the ground, such as under slabs and exterior foundation walls. Look for products with a low global warming potential (GWP), that use carbon dioxide or water as their main blowing agent. You can also ask whether the manufacturer has switched from HBCD flame retardant, a toxic substance that is now being phased out in foam insulation in the European Union and Canada, to less toxic PFR (polymeric flame retardant).

Expanded polystyrene has a high insulation value to save energy, and is one of the few types of insulation that can be used underground, such as under a slab or on the outside of a foundation wall. Unlike extruded polystyrene, expanded typically does not use high global warming potential (GWP) blowing agents, so expanded polystyrene is environmentally preferable to extruded polystyrene. This difference is decreasing as manufacturers of extruded improve their blowing agents.

The first polystyrene was made in 1839 by Eduard Simon in Berlin, of resin distilled from the American sweetgum tree. Today polystyrene is made from petroleum products.