🇨🇦 Canada Compliance · SPC & LVT Flooring · NBC Sound · STC · IIC · ASTC
Multi-Unit Flooring Acoustics in Canada: STC, IIC & ASTC
Acoustic noise between units is the top complaint in multi-family buildings — and Canada handles it differently from the US or the UK. The National Building Code requires airborne sound performance but only recommends impact-sound performance, and since 2015 it added a field measure, ASTC, that changes how compliance is shown. Here is what actually applies to flooring, and where SPC and LVT fit.
Short answer
Canada’s NBC requires airborne sound between dwellings — lab STC 50 or field ASTC 47 (ASTC includes flanking). Impact sound (IIC) is recommended, not required: a bare-floor IIC 55. A rigid SPC/LVT on a hard subfloor does little for impact on its own — it needs an IXPE acoustic backing within a tested floor-ceiling assembly; the assembly is what gets rated, not the finish.
Reviewed June 2026 · National Building Code of Canada · Ontario OBC · General guidance, not acoustic-engineering or code advice.
Four acronyms, two jobs
The ratings Canada uses — and what each measures
Canadian acoustic ratings split into airborne sound (voices, TV) and impact sound (footsteps, dropped objects), each with a lab and a field version:
STC
Sound Transmission Class
Airborne, lab. The traditional measure for a separating wall or floor assembly under ideal conditions. Higher is better.
ASTC
Apparent STC (field)
Airborne, field. Introduced to the NBC in 2015. Includes flanking — sound travelling through junctions, not just the partition — so it reflects what occupants actually hear.
IIC
Impact Insulation Class
Impact, lab. How well a floor-ceiling assembly blocks footfall and thumping to the suite below. Higher is better.
FIIC
Field IIC
Impact, field. The same measure taken in the finished building — closer to real-world performance than the lab IIC.
The key insight: ASTC will always be equal to or lower than the STC for the same construction, because it counts the flanking paths a lab test ignores. That is why a wall built to a lab STC 55 might only deliver ASTC 47 in the field — and why junction detailing matters as much as the partition itself.
The distinction that catches importers out
What the NBC requires vs what it only recommends
This is where Canada differs sharply from the US and UK. Airborne sound is a hard requirement; impact sound is, at the national level, only a recommendation. Get this clear before a project, because it shapes what the floor has to do:
| Sound path | NBC status | Target |
|---|
| Airborne — between dwellings | Required | Lab STC 50 or field ASTC 47 (your choice of compliance route) |
| Airborne — elevator shafts & refuse chutes | Required | STC 55 |
| Impact — floor-ceiling (footfall) | Recommended only | Bare-floor IIC 55 (tested without floor covering) — not mandated nationally |
National Building Code positions; provincial codes (e.g. Ontario’s OBC, which adopted ASTC from 2020) align with the national approach but should be confirmed for the project’s jurisdiction. Future NBC cycles may make impact (IIC) a core requirement — it is not yet. The authority having jurisdiction and the project’s acoustic consultant confirm what applies.
Why footfall is still the №1 complaint
Impact sound: not required, but the thing residents notice
Here is the practical reality. Even though the NBC only recommends impact performance, footstep and impact noise is consistently the most common complaint in multi-family buildings — and hard floor finishes like SPC, LVT, laminate and tile are exactly where it shows up. A developer who builds only to the airborne requirement and ignores impact often ends up with resident complaints, callbacks and, in condo or BTR settings, reputational cost.
That is why most quality Canadian projects target a bare-floor IIC 55 regardless of the Code only recommending it, and why home-owner associations and condo boards frequently set their own minimum — sometimes IIC 55 to 60 for mid-level living. For a developer or builder, treating impact sound as a real design target, not an optional one, is what protects the asset.
The rigid-floor trap: a rigid SPC or LVT plank laid directly on a hard concrete or wood subfloor offers very little impact attenuation on its own — it can even transmit footfall more sharply than carpet did. Achieving a bare-floor IIC 55 with a hard finish almost always requires a resilient acoustic underlay beneath it.
Impact performance is a system, not a finish
The single most important thing to understand: an IIC or FIIC rating belongs to the whole floor-ceiling assembly, not to the flooring product. The same SPC plank can deliver very different impact numbers depending on the subfloor, the underlay, and the ceiling below. A typical hard-finish assembly is built up like this:
SPC / LVT finishthe visible floor — one layer
IXPE acoustic underlaythe resilient layer that does the impact work
Structural slab / subfloorconcrete or wood-frame
Ceiling assembly belowresilient channel, insulation, gypsum
The acoustic underlay — commonly a 1mm IXPE pad, pre-attached or separate — is the layer that turns a hard, sound-transmitting finish into part of a compliant assembly. But the rating still has to be tested for the actual build-up; you cannot read it off the flooring product alone.
What this means in a tender: ask for the IIC/FIIC of the assembly, not a number stamped on the plank. A responsible supplier provides an SPC with a tested IXPE acoustic backing that performs within a compliant build-up — and points you to the acoustic consultant to confirm the system, exactly as on a UK Part E project.
The multi-unit specification
The SPC spec for Canadian multi-family
The multi-unit workhorse
SPC rigid-core click · IXPE acoustic backing
For stacked suites, an
SPC rigid-core click with a 1mm IXPE acoustic backing gives a hard, premium finish that works within an impact-rated floor-ceiling assembly — floating for fast install and plank-by-plank repair, dimensionally stable through Canadian seasonal swings, and compatible with underfloor heating. Product page:
6mm SPC click flooring.
FormatSPC rigid-core click
Acoustic backing1mm IXPE
Airborne routeAssembly to STC 50 / ASTC 47
ImpactAssembly-tested IIC/FIIC
FireCAN/ULC-S102.2 (test-supported)
DimensionalRigid core, stable
UFHCompatible
MOQ800 sqm / SKU
Ecoflors supplies SPC with a 1mm IXPE acoustic backing to support the assembly’s impact performance, and provides samples for assembly testing where your project requires a documented IIC or FIIC. We do not stamp an IIC number on the product, because the rating belongs to your specific build-up — the honest figure comes from testing the assembly. See our CAN/ULC-S102.2 fire guide for the parallel fire requirement.
Canadian developer FAQ
Multi-unit flooring acoustics — questions buyers ask
What acoustic rating does flooring need in a Canadian multi-unit building?
The National Building Code requires airborne sound between dwellings to meet a lab STC of 50 or a field ASTC of 47 (ASTC includes flanking noise). Impact sound is only recommended, not required — a bare-floor IIC of 55. So for a hard finish like SPC or LVT, the airborne requirement is met by the separating assembly, while impact performance, though not mandated nationally, is what residents notice and most quality projects target IIC 55 anyway.
What is the difference between STC and ASTC?
STC (Sound Transmission Class) is a laboratory rating of a single partition under ideal conditions. ASTC (Apparent STC), added to the NBC in 2015, is a field rating that includes flanking — sound travelling through junctions and adjacent elements, not just the partition. Because it counts those extra paths, ASTC is always equal to or lower than the STC for the same construction, and it better reflects what occupants actually hear. The NBC lets you comply via lab STC 50 or field ASTC 47.
Is impact sound (IIC) required by the building code in Canada?
Not at the national level — the NBC recommends a bare-floor IIC of 55 but does not require it, which differs from the US (where IIC is often a code or HOA requirement) and the UK (where impact sound is required under Approved Document E). That said, footfall noise is the most common complaint in multi-family buildings, so most quality Canadian projects and many condo boards set IIC 55 or higher as their own target. Future NBC cycles may make IIC a core requirement.
Does SPC or LVT flooring meet IIC 55 on its own?
No. An IIC or FIIC rating belongs to the whole floor-ceiling assembly — the finish, the acoustic underlay, the structural slab and the ceiling below — not to the flooring product alone. A rigid SPC or LVT laid directly on a hard subfloor does little for impact sound; achieving a bare-floor IIC 55 with a hard finish generally requires a resilient acoustic underlay such as a 1mm IXPE pad, and the rating must be tested for the actual build-up.
What acoustic backing should SPC have for multi-unit projects?
A resilient acoustic underlay, commonly a 1mm IXPE pad, either pre-attached to the plank or installed separately, is what lets a hard SPC finish contribute to a compliant impact-rated assembly. The exact assembly performance depends on the full build-up and must be confirmed by testing or by the project’s acoustic consultant — the underlay supports the result, but the assembly is what is rated.
Does Ecoflors provide an IIC rating for its flooring?
We supply SPC with a 1mm IXPE acoustic backing to support impact performance, and we provide samples for assembly testing where a project requires a documented IIC or FIIC. We do not stamp an IIC number on the product, because the rating belongs to the specific floor-ceiling build-up, not the plank — the honest figure comes from testing the actual assembly, confirmed by your acoustic consultant.
Factory-direct · acoustic-backed SPC · Canada shipments
Spec a floor that works within your acoustic assembly.
Tell us the project — stacked suites, condo, or purpose-built rental — and we supply SPC with a 1mm IXPE acoustic backing, samples for assembly IIC/FIIC testing, and the documentation your acoustic consultant and the authority having jurisdiction need. Honest about what the product does and what the assembly has to be tested for.
SPC + 1mm IXPE acoustic backing · STC 50 / ASTC 47 assembly · CAN/ULC-S102.2 support · HS 3918.10
FOB Ningbo / Shanghai · MOQ 800 sqm / SKU · factory-direct from Changzhou, China since 2017
Disclaimer: General information for developers, builders, contractors and their suppliers, not acoustic-engineering or code-compliance advice. Sound-transmission requirements depend on the building’s occupancy, construction and jurisdiction (National Building Code of Canada and provincial codes such as the Ontario Building Code); airborne requirements are mandatory while national impact (IIC) provisions are recommendations that may change in future code cycles. Acoustic ratings (STC, ASTC, IIC, FIIC) are properties of the complete floor-ceiling assembly, not of a flooring finish alone, and must be determined by testing the actual build-up and confirmed by the project’s acoustic consultant and the authority having jurisdiction. Reviewed June 2026.
