What's the cost to soundproof a sunroom addition so it blocks traffic noise from Carling Avenue?

Soundproofing a sunroom addition to block traffic noise from Carling Avenue in Ottawa typically costs $10,000 to $30,000 above standard construction costs, depending on the size of the sunroom, the amount of glazing, and how aggressively you need to attenuate the noise. Carling Avenue is one of Ottawa's busiest arterial roads with consistent traffic, transit buses, and emergency vehicle sirens from nearby hospitals — you are dealing with a broadband noise source that spans low-frequency truck rumble through high-frequency tire whine, which makes it a demanding soundproofing challenge.
The windows are the weakest link in any sunroom, and since sunrooms are typically 40 to 70 percent glass, this is where most of your acoustic budget needs to go. Standard double-pane windows achieve roughly STC 28 to 32, which is inadequate for a busy road like Carling. Upgrading to triple-pane windows with laminated glass (which has a PVB interlayer that damps vibration) brings you to STC 35 to 40, and this is the minimum you should consider. The premium for acoustic-rated windows over standard builder-grade runs $300 to $800 per window, and a typical sunroom might have 6 to 12 window units. For the highest performance, asymmetric glazing — where the pane thicknesses differ (for example, 6mm outer, 4mm middle, 8mm laminated inner) — prevents the coincidence dip that occurs when identical panes resonate at the same frequency. These premium acoustic windows can reach STC 40 to 45 and cost $800 to $1,500 per unit installed.
Beyond the Glass: Walls, Roof, and Sealing
The solid wall sections of your sunroom — even if they only make up 30 to 40 percent of the envelope — need to perform well enough that they do not become the weak link once you have upgraded the windows. A wall assembly with 2x6 framing, Rockwool insulation, sound isolation clips, hat channel, and double 5/8-inch Type X drywall with Green Glue can achieve STC 55 to 60, well above what the windows deliver, which is exactly what you want — the overall room performance will be governed by the weakest element (the glass), so the walls should overperform. The roof section needs similar attention, particularly if it is a low-slope or flat-roof sunroom design where rain and ice noise compound the traffic noise issue. Budget $15 to $25 per square foot for the wall and roof acoustic assemblies.
Air sealing is absolutely critical in a sunroom facing a busy road. Every gap around window frames, at wall-to-roof joints, and where the addition meets the existing house must be sealed with acoustic caulk — a 1 percent gap in your envelope can reduce performance by 10 dB, which would undo thousands of dollars of window upgrades. Ottawa's extreme temperature swings from -30°C to +35°C cause materials to expand and contract, so use sealants that remain permanently flexible rather than rigid foam or standard caulk that will crack over time.
For a sunroom addition along Carling Avenue, having the design reviewed by a soundproofing professional before construction begins is far more cost-effective than retrofitting after the fact. The window specifications, wall assembly details, and air-sealing strategy all need to work together as a system. Sound IQ can help you understand the noise levels you are dealing with and connect you with contractors experienced in building acoustically sound additions in Ottawa's challenging climate.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:HomeupgradersRenoMotion Inc.Master TapersDreamwood Construction & RenovationsThe Next RenoView all contractors →