Spray Insulation Vs. Mineral Wool Sound

Spray Insulation

• Spray insulation entails exactly what it sounds like, insulation that comes in spray form. Usually made from polyurethane, you apply spray insulation to building frames as a liquid. This liquid rapidly hardens and expands 30 to 50 times its original volume. Two basic types of spray insulation exist, open cell and closed cell. Closed cell spray insulation forms denser material with tighter bonds than open cell, making it a better material for heat insulation. Applying spray foam involves complex equipment and numerous safety procedures and is therefore usually left to professionals.

Mineral Wool

• Mineral wool insulation usually denotes one of two materials: rock wool or slag wool. Rock wool constitutes a wool-like insulation material made of woven fibers of minerals like basalt. Slag wool consists of a similar material made from scum that forms on the surface of molten metal. According to the United States Department of Energy, mineral wool contains an average of 75 percent recycled material. The material is classified as incombustible, meaning it doesn't burn, and proves capable of withstanding temperatures as high as 1652 degrees Fahrenheit.

As Sound Insulation

• According to manufacturers, mineral wool and spray insulation provide some sound dampening, though each works primarily as a heat insulator. Spray insulation helps protect airflow and preserve heat in homes, decreasing energy bills and carbon emissions. Mineral wool helps provide heat insulation in areas with fire hazards, given its incombustible nature and extreme heat resistance. Some manufacturers create sheets of material from mineral fibers as acoustic insulation, though this insulation usually assumes the form of mineral fiber boards, not wool. Similarly, spray insulation can help control sound reverberation, but is not a primary material for sound insulation.

Fundamental Differences

• Several fundamental differences exist between mineral wool and spray insulation. Spray insulation, for instance, describes a delivery method, not the material within the insulation. Though most manufacturers use polyurethane or a similar material, technically speaking, spray insulation constitutes any insulation applied as a liquid and allowed to harden and expand. Mineral wool only constitutes wool-like materials made from stone or metal minerals. Furthermore, spray insulation bonds directly with surfaces, while mineral wool sits in between walls and frames, like stuffing.