Soundproofing and acoustic insulation in Canadian homes
Noise control depends on the whole assembly, not one product. This page explains the difference between airborne and impact noise, what STC and IIC do and do not tell you, and how to write a brief that gets comparable contractor quotes. No material prices are published here.
What is the difference between soundproofing insulation and acoustic insulation?
In practice the terms are used interchangeably for sound-absorbing batts placed inside a wall, ceiling or floor cavity. Insulation alone rarely solves a noise problem: results depend on the whole assembly — mass, decoupling, air sealing, and flanking paths around the assembly. Describe the noise you hear, then let a contractor design the assembly.
- Jurisdiction
- Canada — the National Building Code is a model code adopted with changes by each province
- Page reviewed
- 2026-08-31
What affects the amount
- Whether the noise is airborne (voices, TV, music) or impact (footsteps, dropped objects)
- Mass of the assembly — number and thickness of layers of board
- Decoupling — resilient channels, sound clips, staggered or double studs
- Cavity absorption — sound-rated batts inside the cavity
- Air sealing — gaps at outlets, perimeters, doors, and penetrations
- Flanking paths — sound travelling through floors, ductwork, and side walls
- Doors and windows, which are often the weakest element in a room
What to verify yourself
- What noise you actually hear, at what time, and from where
- The existing construction of the wall, ceiling, or floor before designing a fix
- The requirements your province's adopted building code places on separations between dwelling units
- Condominium rules on floor coverings, underlay, and alterations
- Whether a permit is required for the work you are proposing
- What rating, if any, the contractor is designing to, and how it will be documented
Who to ask
- A contractor or renovator experienced in acoustic assemblies
- An acoustical consultant, for a measured problem or a dispute
- Your condominium corporation or property manager, before altering floors or walls
- Your municipal building department, about permits
- The manufacturer, for tested assembly listings for their specific products
Airborne noise versus impact noise
These two problems have different solutions. Identifying which one you have is the single most useful thing you can do before spending money.
| Airborne noise | Impact noise | |
|---|---|---|
| What it sounds like | Voices, TV, music, traffic, barking | Footsteps, dropped objects, furniture dragging, plumbing knocks |
| How it travels | Through the air, then through the assembly | Through structure by direct physical contact |
| Usual approach | Add mass, seal air paths, absorb in the cavity, decouple layers | Interrupt the structural path: underlay, floating floors, resilient supports |
| Planning rating discussed | STC / ASTC | IIC |
| Common mistake | Adding batts only and expecting a large change | Treating the ceiling below instead of the floor above |
STC, ASTC and IIC as planning concepts
STC (Sound Transmission Class) is a single-number rating of how much airborne sound a tested assembly blocks in a laboratory. ASTC (Apparent Sound Transmission Class) is the field-oriented concept that also accounts for flanking sound travelling around the assembly, which is why a real room usually performs below the lab number. IIC (Impact Insulation Class) rates impact sound through a floor–ceiling assembly.
Use these as planning vocabulary for your conversation with a contractor. A higher number generally means better performance, but a rating only applies to the exact tested assembly, correctly built. We do not publish target numbers here: the requirement that applies to you comes from the building code your province has adopted, and from your condominium's rules.
| Rating | Describes | Use it for |
|---|---|---|
| STC | Airborne sound blocked by a tested assembly, in a lab | Comparing assemblies on paper |
| ASTC | Airborne performance including flanking paths, oriented to the finished building | Setting realistic expectations |
| IIC | Impact sound through a floor–ceiling assembly | Footstep and dropped-object noise |
| NRC (absorption) | How much sound a surface absorbs within a room | Echo and reverberation inside one room |
Walls, ceilings and floors
| Assembly | Levers that generally matter | Ask the contractor |
|---|---|---|
| Interior partition wall | Cavity batts, extra board layer, sealing at perimeter and outlets, solid-core door | What is the existing framing, and what assembly are you proposing? |
| Party wall between units | Decoupling, mass, sealing; alterations may be restricted | Is this a shared element, and is a permit or board approval required? |
| Ceiling below a noisy floor | Resilient channel or clips, added board, cavity absorption; impact noise still travels structurally | Will this address footsteps, or only airborne sound? |
| Floor above | Underlay, floating assembly, area rugs, appliance and furniture isolation | Do condo rules specify an underlay or coverage percentage? |
| Mechanical and flanking paths | Ducts, recessed lights, back-to-back outlets, plumbing chases | How are penetrations being sealed and detailed? |
Printable questions for your contractor or condo board
Bring these to your site visit or board request. Nothing you type is stored or sent.
- Based on what I described, is this mainly airborne noise, impact noise, or both?
- What exactly is the existing assembly, and how did you determine that?
- What assembly are you proposing, layer by layer?
- Is that a tested assembly, and can you show me the listing?
- How will air sealing and penetrations be handled?
- What flanking paths remain after this work, and what will they cost me in results?
- What realistic change should I expect, and what will still be audible?
- Is a permit required, and who pulls it?
- Condo board: what approvals, rules, and underlay requirements apply?
- Condo board: is this element part of the unit or part of the common property?
- What is included and excluded in the quote, including finishing and paint?
- How long will the space be unusable?
Project brief builder
Contractors quote more accurately when you describe the noise rather than prescribe a product. Fill this in, then print or copy it into your enquiry. Nothing is stored or sent.
Questions people ask
Sources & methodology
- Jurisdiction
- Canada
- Applies to
- Airborne and impact sound ratings (STC / ASTC / IIC) as planning concepts
- Source link checked
- 2026-08-31
- Rule effective date
- Not asserted — confirm the effective rule directly with the source above.
- Jurisdiction
- Canada (model code; adopted with changes by each province)
- Applies to
- Sound transmission requirements between dwelling units and construction standards
- Source link checked
- 2026-08-31
- Rule effective date
- Not asserted — confirm the effective rule directly with the source above.
- Jurisdiction
- Canada (model code), applied provincially and municipally
- Applies to
- Which construction rules apply, and why permits, inspections, and closed-permit records are handled by your local authority
- Source link checked
- 2026-08-31
- Rule effective date
- Not asserted — confirm the effective rule directly with the source above.
Assumptions
- STC, ASTC, and IIC are described as planning concepts only; no target value is asserted for your project.
- Code requirements are assumed to come from the code your province has adopted, which may differ from the model national code.
- No product performance, price, or decibel reduction is claimed.
What this estimate does not include
- A design for your specific assembly, which requires a contractor or acoustical consultant.
- Any guarantee of noise reduction or measured outcome.
- Condominium rules and approvals, which are set by your corporation.
Every source used anywhere on this site — with the date its link was checked, what it establishes and what it does not — is listed in the home cost source ledger.