The Difference between Expanded Polystyrene and Extruded Polystyrene
The main difference between these two materials lies in their density. Extruded polystyrene is much denser than expanded polystyrene (2.18 lbs. on average for XPS vs. 0.93 lbs. for EPS).
The Advantages of Expanded Polystyrene
EPS is a lightweight insulator with a high mechanical resistance. Its lightness makes it easy to handle and install. It’s primarily used in the form of white or grey panels to insulate floors, walls, roofs, or terraces.
It’s worth noting that grey EPS shows a better thermal performance (around 10 to 20%), which makes it possible, for example, to reduce the thickness of the polystyrene panel when it’s used as insulation. However, grey polystyrene is slightly more expensive.
As it’s quite fragile when it comes into contact with fire, it’s necessary to combine expanded polystyrene with a non-combustible material. Plaster is often used with expanded polystyrene and combined in the form of a plate. These plates are mainly appreciated for interior insulation.
The Advantages of Extruded Polystyrene
XPS has good thermal conductivity (generally higher than EPS). It’s also highly resistant to different temperatures: heat, cold, and water are usually unsuccessful at overcoming quality extruded polystyrene. It’s therefore preferred in areas with rather extreme weather conditions.
Extruded polystyrene has other advantages. For example, it’s equipped with a higher mechanical resistance than EPS. It doesn’t warp much, even over time, and doesn’t lose its thickness. These qualities are especially appreciated in Québec.
XPS is primarily used in the form of blue panels for insulating floors and roofs (flat).
Polystyrene panels and decoration
Polystyrene panels are very useful when it comes to decorating a place. For example, whether it’s a stage play or a shop display case to be decorated, these panels can act as false partitions and create a specific atmosphere if they’re dressed up. Lightweight, they’re very easy to transport. However, it’s worth noting that expanded polystyrene panels are more suitable for decoration: they’re lighter and less expensive. In addition, it’s not necessary to use a highly insulating material as a decorative element; the cheaper option should be more than sufficient.
Those who want to create specific shapes will have more reasons to hesitate between expanded and extruded polystyrene. Once it’s cut, the panel will be transformed into a fully fledged decorative element. If it’s only handled a little, expanded polystyrene will largely do the trick. On the other hand, if this element needs to have a minimum resistance, then it will be better to opt for extruded polystyrene.
As you can see, these materials may seem very similar, but they have very different qualities. Remember that expanded polystyrene is simply lighter, thicker, and less insulating than extruded polystyrene. It’s also less expensive and more manageable for those who don’t have machines adapted to its cutting.