How do I stop plumbing stack noise from my neighbour's unit travelling through the shared chase in my condo?

Stopping plumbing stack noise from travelling through a shared chase in your condo requires treating both the pipes themselves and the chase enclosure, because sound reaches you through two distinct paths: structure-borne vibration from water rushing through the pipes transferring into the framing, and airborne noise radiating from the pipes into the chase cavity and then through the chase walls into your unit. A thorough treatment addressing both paths typically costs $1,500–$4,500 and can reduce plumbing noise by 15–20 dB — enough to make flushes and showers from the neighbouring unit virtually unnoticeable.
The first priority is wrapping the exposed drain pipes within the chase. The main 3-inch or 4-inch ABS drain stack is the loudest culprit, especially during toilet flushes where water drops vertically and impacts direction changes at fittings. Wrapping the stack with mass loaded vinyl (MLV) at 1 lb/sqft density ($1.50–$3.00 per square foot) adds mass that dampens the pipe's vibration. For best results, wrap the MLV around the pipe with the mass side facing out and secure it with acoustic tape — do not compress the MLV tightly against the pipe, as a small air gap actually improves performance. Some professionals use a layered approach: closed-cell foam pipe insulation first (to decouple), then MLV over top, which addresses both vibration and airborne noise. Material cost for wrapping a typical 10-foot vertical run plus fittings is $150–$400.
Equally important is isolating the pipe hangers and supports. In most Ottawa condos, the plumbing stack is supported by rigid metal hangers that bolt directly to the wood framing — each hanger acts as a direct vibration bridge from the pipe into your walls and ceiling. Replacing these with rubber-cushioned pipe clamps ($8–$15 each) breaks the vibration path at every support point. There are typically 3–5 hangers in a single-storey chase run, so this is a $50–$100 upgrade in materials that delivers outsized results. Supply lines (copper or PEX) can also transmit noise, particularly the water hammer that occurs when valves close suddenly — installing a water hammer arrestor ($20–$50) on the supply lines within the chase addresses this specific issue.
The chase enclosure itself needs attention. If the chase wall on your side is just a single layer of 1/2-inch drywall on studs — which is common in many Ottawa condos built in the 1990s and 2000s in areas like Kanata, Barrhaven, and Orleans — upgrading it to a proper sound-rated assembly makes a dramatic difference. Fill the chase cavity around the pipes with Rockwool Safe'n'Sound mineral wool (do not compress it tightly — loose-fill is more effective for absorption). Then add resilient channel to the stud face on your side, followed by a layer of 5/8-inch Type X drywall with Green Glue compound and a second layer of 5/8-inch drywall. Seal every edge and penetration with acoustic caulk. This wall upgrade runs $800–$2,000 for a typical chase wall of 20–30 square feet and is the single most effective step for persistent plumbing noise.
Before opening up the chase, confirm with your condo corporation whether the chase is within your unit boundary or is a common element — this determines who is responsible and what approvals you need. A soundproofing professional can also check for additional flanking paths through the floor and ceiling where the stack passes through, which are often the overlooked weak link. The Ottawa Contractor Directory can help you find contractors experienced with plumbing noise isolation in condo buildings.Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:HomeupgradersRenoMotion Inc.ART DRYWALL AMD PAINTINGJoe Imerti ContractingDenys Builds Designs RenovationsView all contractors →