Expanded Clay Aggregate (ECA ®) has a highly porous and irregular surface. This means that is extremely effective at sound insulation. Sound waves that hit a concrete surface are reflected, which causes loud echoing. ECA ®, in contrast, absorbs the majority of sound waves. When added to plaster, or to concrete to create wall panels, ECA ® is extremely useful for sound or acoustic insulation and can help create acoustically-tuned rooms. And, due to its low cost and the ease of working with this material, it’s a perfect choice for large-scale building projects, including commercial lobbies and other such large spaces.