How much does it cost to add acoustic batt insulation to all exterior walls during a gut reno?

Adding acoustic batt insulation to all exterior walls during a gut renovation in Ottawa typically costs $3,500 to $9,000 for a standard three-bedroom home, covering material and installation labour. On a per-square-foot basis, expect $1.50 to $3.50 installed depending on the product you choose and the complexity of the wall cavities. During a gut reno, this is one of the most cost-effective acoustic upgrades available because the walls are already open — there is no demolition or patching cost, which would otherwise double or triple the price.
The two most common products for this application are Rockwool Safe'n'Sound at $1.20–$1.80 per square foot for material and Owens Corning QuietZone at $1.00–$1.50 per square foot. Both are mineral wool batts designed specifically for sound absorption and are friction-fit into stud cavities without requiring fasteners. Rockwool Safe'n'Sound is the more popular choice in Ottawa due to its superior density (approximately 2.5 lbs/cubic foot versus standard fibreglass at 0.5–1.0 lbs/cubic foot), higher melting point for fire safety, and excellent moisture resistance — all important qualities given Ottawa's extreme temperature swings and the critical role exterior walls play in the building envelope.
For a typical Ottawa home with roughly 1,500 to 2,500 square feet of exterior wall cavity area, here is how the numbers break down. Material cost for Rockwool Safe'n'Sound runs $1,800–$4,500 depending on total area. Installation labour during an open-wall gut reno is efficient — an experienced crew can insulate exterior walls at a rate that adds only $0.50–$1.50 per square foot to the project since the framing is already exposed. Compare this to a retrofit scenario where you would need to remove existing drywall ($2–$4 per square foot for demolition) and replace it afterward ($4–$8 per square foot for new drywall, tape, and paint), and the value of doing this work during a gut reno becomes clear.
One important consideration for Ottawa homes: your exterior walls need both thermal insulation and a properly placed vapour barrier on the warm side of the assembly. Acoustic batt insulation in exterior walls serves double duty — it improves both thermal performance and sound absorption. However, it is critical that your contractor coordinates the acoustic insulation with the overall wall assembly design. In Ottawa's climate, where temperatures routinely drop below -25°C in January and February, an improperly detailed vapour barrier can lead to condensation within the wall cavity, which degrades both the insulation and the framing over time.
Keep in mind that insulating the cavities alone provides moderate acoustic improvement — roughly 3–5 STC points on a standard exterior wall. If you are dealing with significant traffic noise from a busy road in neighbourhoods like Merivale, Baseline, or along the Queensway corridor, you will want to combine the cavity insulation with additional measures such as resilient channels or isolation clips and a second layer of drywall to achieve meaningful noise reduction. Since your walls are already open during the gut reno, adding these components at the same time is far more economical than coming back later. Sound IQ can help you evaluate which combination of treatments makes sense for your specific noise challenges and budget.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:Reno's by Daniel FrauwallnerRenoMotion Inc.TH Custom WoodworkTiptop ContractingREJUVENATION RENOVATIONSView all contractors →