Are recycled denim insulation batts as effective as mineral wool for soundproofing interior walls?

Recycled denim insulation, such as UltraTouch by Bonded Logic, provides decent acoustic performance but falls measurably short of mineral wool products like Rockwool Safe'n'Sound for dedicated soundproofing applications. While denim batts are an excellent eco-friendly choice for thermal insulation, if your primary goal is sound control, mineral wool is the better performer.The difference comes down to density and fibre structure. Rockwool Safe'n'Sound has a density of approximately 2.5 pounds per cubic foot, while recycled denim batts typically come in at 1.0 to 1.5 pounds per cubic foot. In acoustics, density matters significantly for low-frequency absorption. Higher-density mineral wool absorbs more sound energy across a wider frequency range, particularly in the low-to-mid frequencies (125 Hz to 500 Hz) where voices, TV sound, and music are most problematic. In standardized testing, a wall assembly with Rockwool Safe'n'Sound typically achieves 3 to 5 STC points higher than the same assembly with denim insulation, which translates to a noticeable real-world difference.Cost and Performance Comparison for Ottawa ProjectsIn the Ottawa market, Rockwool Safe'n'Sound runs approximately $1.20 to $1.80 per square foot for standard 2x4 wall batts, while recycled denim insulation costs $1.50 to $2.50 per square foot, making denim both less effective acoustically and more expensive. This makes mineral wool the clear winner on a performance-per-dollar basis for soundproofing. Denim insulation is also more difficult to source in Ottawa, as it is typically a special order item, whereas Rockwool Safe'n'Sound is stocked at most Home Depot and Lowes locations across the city and available same-day.Mineral wool has additional advantages in Ottawa's building environment. It is naturally fire resistant with a melting point above 1,000C, which helps maintain the fire ratings required by the Ontario Building Code for party walls and rated assemblies. Denim insulation is treated with borate for fire resistance, which is effective but adds a chemical treatment to what is marketed as a natural product. Mineral wool is also moisture resistant and will not absorb water or support mould growth, which is relevant in Ottawa where condensation in wall cavities is a concern during our long heating season. Denim insulation can absorb moisture and is slower to dry out, potentially creating conditions for mould in improperly detailed wall assemblies.There is one scenario where denim insulation makes sense even for acoustic applications. If you are doing a green building project where environmental credentials and recycled content are paramount, and the wall assembly already includes robust decoupling with sound isolation clips and hat channel, the insulation type becomes less critical to overall performance. In a well-decoupled assembly, the difference between denim and mineral wool might be only 1 to 2 STC points, since the clips and air gap are doing most of the heavy lifting. In that context, choosing denim for its environmental benefits is a reasonable trade-off.For most Ottawa homeowners tackling a soundproofing project, mineral wool remains the standard recommendation. It performs better, costs less, is easier to source locally, and integrates well with fire-rated assemblies. If you want expert guidance on choosing the right insulation for your specific wall assembly, Sound IQ is here to help, and the Ottawa Contractor Directory at justynrookcontracting.com/directory can connect you with insulation professionals who specialize in acoustic applications.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:613BinsRenoMotion Inc.Somar Contracting Inc.Dump n Dash HaulingREJUVENATION RENOVATIONSView all contractors →