Gearslutz.com - View Single Post - Polystyrene insulation as a sound insulation.

Bob Ross · 24th May 2007

FWIW, my dad, who was in the plastics industry for 20+ years (sales & marketing, not engineering, so you should take this with a big grain of salt) insists that closed-cell expanded polystyrene foam insulation -- the stuff that (often incorrectly) gets referred to as Styrofoam® -- does exhibit some soundproofing properties when used as the middle layer in a sandwich between sheetrock and/or plywood leaves.

He suspects that due to the the irregular, non-uniform shape of the expanded plastic beads, as well as perhaps the compliant nature of the material, sound transmission is impeded through the EPS board.

I can think of plenty of reasons why it would be preferable to use RockWool (or the equivalent) rather than EPS...but I guess I can also see how EPS could fulfill certain requirements both acoustical and environmental.

It's definitely *not* commonly used for its sonic properties.

24th May 2007	#5
Bob Ross Lives for gear Joined: Mar 2005 Location: NYC Posts: 2,637	FWIW, my dad, who was in the plastics industry for 20+ years (sales & marketing, not engineering, so you should take this with a big grain of salt) insists that closed-cell expanded polystyrene foam insulation -- the stuff that (often incorrectly) gets referred to as Styrofoam® -- does exhibit some soundproofing properties when used as the middle layer in a sandwich between sheetrock and/or plywood leaves. He suspects that due to the the irregular, non-uniform shape of the expanded plastic beads, as well as perhaps the compliant nature of the material, sound transmission is impeded through the EPS board. I can think of plenty of reasons why it would be preferable to use RockWool (or the equivalent) rather than EPS...but I guess I can also see how EPS could fulfill certain requirements both acoustical and environmental. It's definitely not commonly used for its sonic properties.