Sound privacy is an important part of modern construction, especially in condominiums, apartments, duplexes, home offices, and basement suites. At Bonum Drywall, we install professional acoustic drywall systems designed to reduce noise transfer between rooms and dwelling units.
Acoustic drywall or sound-dampening drywall is a specialized gypsum board designed to reduce sound transmission compared to standard drywall. Its layered construction helps dissipate sound energy and improve overall sound isolation within wall and ceiling assemblies.
When installed correctly with proper framing, insulation, and sealing techniques, acoustic drywall can significantly improve privacy, comfort, and noise control inside a building.
STC stands for Sound Transmission Class, a numerical rating that measures how effectively a wall or floor assembly reduces airborne sound transmission, such as speech, television noise, or music.
STC ratings are determined in laboratory test chambers under controlled conditions. Because these tests occur in ideal environments, they represent the maximum theoretical performance of a wall or floor system.
In real buildings, sound travels through additional paths such as ceilings, floors, and structural framing. Because of this, Canada uses ASTC (Apparent Sound Transmission Class), which measures sound isolation in real-world field conditions.
ASTC accounts for flanking sound, meaning noise that bypasses the wall through:
Because of these additional sound paths, ASTC ratings are typically 5–10 points lower than laboratory STC ratings.
The Ontario Building Code requires a minimum ASTC rating of 47 for separating assemblies between dwelling units.
This requirement applies to assemblies governed by Part 5 and Part 9 of the code and focuses on total sound transmission, including both direct sound through the wall and flanking sound around it.
Typical ASTC performance ranges can be interpreted as follows:
ASTC 40–44
Below standard. Loud speech can be heard clearly and privacy is limited.
ASTC 45–49
Meets typical residential building code requirements.
ASTC 50–54
Good sound privacy. Normal conversation is generally not heard.
ASTC 55–60+
Excellent sound isolation with strong acoustic privacy.
Higher ASTC ratings provide better acoustic comfort and are often preferred in condos, home offices, media rooms, and rental units.
STC and ASTC ratings are primarily designed to measure performance against speech-frequency sounds. They do not fully capture low-frequency noise below 125 Hz, such as:
Additional acoustic design strategies may be required when controlling low-frequency noise.
Acoustic drywall offers significantly improved sound dampening compared to standard drywall.
Typical performance levels include:
For best results, acoustic drywall systems are often combined with:
These components work together to create a complete sound-control system rather than relying on drywall alone.
The quality of installation is one of the most important factors in maintaining acoustic performance.
Sound can travel through unintended paths known as flanking routes, including:
Even small gaps can significantly reduce the effectiveness of a soundproofing system.
To ensure optimal system performance, professional acoustic installations typically include:
These techniques help prevent sound leakage and maintain the designed acoustic rating.
Acoustic drywall systems are commonly used in:
They are particularly valuable in multi-unit residential buildings where sound privacy is essential.
At Bonum Drywall, we provide professional drywall installation and finishing services across:
Our team focuses on precision installation, proper sealing, and code-compliant construction to help ensure the best acoustic performance possible.
✅ Need better sound isolation in your home or project?
Contact Bonum Drywall to discuss acoustic drywall installation for your space.
