How effective is QuietRock compared to double-layer standard drywall for soundproofing in a Toronto home?

QuietRock and double-layer standard drywall with Green Glue deliver comparable STC performance — both achieve roughly STC 50–55 as standalone wall upgrades — but they differ significantly in cost, thickness, weight, and installation practicality. For most Toronto homeowners, the choice comes down to whether you value thinner profile (QuietRock) or lower cost (double drywall with Green Glue).

QuietRock is a engineered soundproof drywall panel with a viscoelastic polymer core laminated between gypsum layers. The polymer converts sound vibration into heat, similar to how Green Glue works but built directly into the board. A single 5/8-inch QuietRock panel on a standard stud wall with insulation achieves approximately STC 50–53, compared to STC 38–42 for a single layer of standard 5/8-inch drywall on the same wall. That 10–12 point improvement from a single board swap is impressive. QuietRock panels cost $55–$90 per 4x8 sheet in the GTA market — roughly 3–4 times the cost of standard 5/8-inch drywall at $18–$26 per sheet.

Double-layer standard drywall with Green Glue involves hanging a first layer of 5/8-inch drywall, applying Green Glue Noiseproofing Compound ($15–$20 per tube, two tubes per sheet), and then screwing a second layer of 5/8-inch drywall on top with staggered joints. This assembly on a standard stud wall with insulation achieves approximately STC 50–55 — matching or slightly exceeding QuietRock's single-layer performance. The material cost for the double-layer approach runs roughly $50–$75 per 4x8 area (two sheets of drywall at $18–$26 each plus $30–$40 for two tubes of Green Glue), which is comparable to or slightly less than a single QuietRock sheet.

So if the STC performance is similar and the material cost is close, why would you choose one over the other?

Choose QuietRock when space is at a premium. A single QuietRock panel is 5/8-inch thick. A double-layer drywall assembly is 1-1/4 inches thick. In Toronto condos where every inch of floor space translates to significant dollar value, losing an extra 5/8 inch on every soundproofed wall adds up. For a condo with two party walls, the double-layer approach effectively shrinks your unit by roughly 10–15 square feet of usable floor area compared to QuietRock — and in Toronto's condo market, that square footage has real monetary value. QuietRock also means less weight on the wall structure, which can matter in high-rise condos with metal stud framing.

Choose double drywall with Green Glue when budget is the priority or when you are already doing resilient channel work. The real-world installed cost difference favours the double-layer approach in most GTA projects. While material costs are similar, QuietRock requires specialized handling (it is heavier and more expensive to waste on bad cuts), and some GTA drywall contractors charge a premium for working with it due to limited experience with the product. Double drywall with Green Glue uses standard materials that every drywall crew handles daily, keeping labour costs lower. For a typical room with 350 square feet of wall area, the installed cost runs roughly $3,500–$5,500 for QuietRock on resilient channel versus $3,000–$4,500 for double drywall with Green Glue on resilient channel.

The performance comparison shifts when you add resilient channel to both assemblies. QuietRock on resilient channel with insulation achieves approximately STC 56–60. Double drywall with Green Glue on resilient channel with insulation achieves approximately STC 58–63. At this level, the double-layer assembly with Green Glue slightly outperforms QuietRock because the system has more mass (two separate gypsum boards) plus both damping (Green Glue) and decoupling (resilient channel). However, the difference of 2–3 STC points is barely perceptible to the human ear.

For Toronto basement home theatres and music rooms where maximum performance is the goal, many GTA contractors recommend combining QuietRock with Green Glue on resilient channel — using QuietRock as the first layer and a standard 5/8-inch board as the second layer with Green Glue between them. This "best of both worlds" approach achieves STC 63+ but comes at a premium cost.

Both approaches require professional installation. Green Glue application is straightforward but messy, and the second drywall layer must be hung before the Green Glue skins over (within 15 minutes of application). QuietRock must be scored and snapped carefully — wasted sheets at $55–$90 each are expensive mistakes. Either way, the resilient channel installation is the most critical element and must be done by an experienced drywall contractor who understands that a single short-circuit screw defeats the entire system. Need help finding a drywall installer? Toronto Drywall Installers can match you for free.