Everything your strata council wants to see before it approves your new floor — in one download.
If you own a condo in Canada, you already know the drill: before you can replace your flooring, your strata council wants proof that the new floor won’t send footstep noise into the unit below. Most flooring stores answer with a marketing brochure. We answer with test reports.
Cork is the original acoustic floor, and we’ve been testing ours for decades — impact sound reduction to ISO 717-2 and ISO 140-8, Delta IIC assemblies to ASTM E2179, and full STC/IIC ratings for every cork underlayment we sell, on a standard 6-inch concrete slab, with and without a suspended ceiling. No inflated lab fantasy numbers. Just documents your strata can actually read.
Download the Kit (ZIP)Most strata bylaws reference one of three numbers. They are not interchangeable, and understanding the difference is the fastest way to get approved:
IIC (Impact Insulation Class) rates how well a floor-ceiling assembly blocks impact sound — footsteps, dropped objects, chair legs. It is measured on the whole structure: slab, ceiling, insulation, and floor covering combined. A bare 6-inch concrete slab typically tests around IIC 27 on its own.
STC (Sound Transmission Class) is the same idea for airborne sound — voices, TV, music. Strata councils sometimes quote STC minimums alongside IIC.
ΔIIC (Delta IIC, ASTM E2179) measures only the improvement the flooring and underlay contribute, with the slab’s contribution mathematically removed. It is the one number that travels from building to building, and the only fair way to compare two products. As a rule of thumb: ΔIIC 14 is a good acoustic floor; ΔIIC 20 is excellent. Thin foam underlays typically contribute single digits to low teens.
ΔLw (EN ISO 717-2) is the European equivalent — impact sound reduction in decibels. Our European-made lines (Swiss Design cork, TechSlate) are rated this way: 18–19 dB.
When a bylaw says “IIC 50” or “IIC 72,” it is talking about the finished assembly in your unit — which is why the kit includes both the per-product test statements and a cover letter that shows the assembly math.
Every figure below is taken from a hosted test document. The source file for each row is linked — the same files that are inside the kit.
| Product / system | Tested result | Standard | Source document |
|---|---|---|---|
| 3mm cork underlayment | IIC 39 / STC 40 (6″ concrete, no suspended ceiling); IIC 53 / STC 54 (with suspended ceiling) | Assembly test | Test statement (PDF) |
| 6mm cork underlayment | IIC 50 / STC 51 (no ceiling); IIC 64 / STC 65 (with suspended ceiling) | Assembly test | Test statement (PDF) |
| 12mm cork underlayment | IIC 75 / STC 76 (no ceiling); IIC 89 / STC 90 (with suspended ceiling) | Assembly test | Test statement (PDF) |
| 12mm cork floating flooring (e.g. Silver Birch FSB12) | IIC 55 (5.5″ concrete, no suspended ceiling); 19 dB impact noise reduction | ISO 140-8 | Test report (PDF) |
| 11mm Swiss Design cork floating (e.g. Sandstorm FSan11) | 18 dB impact sound reduction (ΔLw) | EN ISO 717-2 | Test report (PDF) |
| 10mm cork floating lines (Terrazzo, Sustainazzo, Shoreline, Venetian) | 19 dB impact sound reduction (ΔLw), tested at 11mm | EN ISO 717-2 | Test report (PDF) |
| Grano 10mm cork floating | 18 dB impact sound reduction (ΔLw) | EN ISO 717-2 | Figure per product listing |
| Swiss TechSlate 7.5mm (e.g. Bright Stone) | Approx. 19 dB impact sound improvement | EN ISO 717-2 | Figure per product listing |
| 6mm glue-down cork tile | 18 dB impact sound reduction | — | Figure per product listing |
| 11mm cork floating floor + 6mm cork underlayment | ΔIIC +20 | ASTM E2179 (NGC report 7013034) | Test summary (JPG) |
| Combination | Total tested sound reduction | Source document |
|---|---|---|
| 12mm floating floor + 3mm cork underlayment | 31 dB | Test sheet (JPG) |
| 12mm floating floor + 6mm cork underlayment | 42 dB | Test sheet (JPG) |
| 12mm floating floor + 12mm cork underlayment | 67 dB | Test sheet (JPG) |
Best acoustic result — “the strata special.” 12mm cork floating flooring over 12mm cork underlayment. Tested at 67 dB total sound reduction; the underlayment alone carries IIC 75 / STC 76 on 6-inch concrete. For wood-frame buildings and the strictest councils.
Best value — the tested assembly. Any 11–12mm cork floating floor over 6mm cork underlayment. This is the exact combination tested to ΔIIC +20 (ASTM E2179) — the number to lead with in the cover letter, because it is building-independent. The 12mm floating version of this pairing tests at 42 dB total reduction.
Slim profile / over radiant heat. Swiss Design 11mm cork floating — 18 dB (EN ISO 717-2), no separate underlayment required thanks to its attached cork underlay layer. Where ceiling height or hydronic heat rules out thick assemblies.
Glue-down route (where strata requires bonded floors). 6mm glue-down cork tile at 18 dB impact sound reduction.
Design-led. Swiss TechSlate 7.5mm — stone visuals at approx. 19 dB (EN ISO 717-2), for owners who need approval and a non-cork look.
One zip file with everything your strata council needs:
It means the whole floor/ceiling assembly — slab, ceiling, and your floor together — must reach IIC 50. Ask your strata or property manager what the building already tests at. A 6-inch concrete slab on its own is typically around IIC 27; our tested cork systems add the rest. The cover letter in the kit walks your council through the math.
Yes — and wood frames need the most help, because a wood-joist structure transmits far more impact sound than a concrete slab. A floating cork floor over cork underlayment is the combination most often approved in wood-frame strata buildings; lead with the ΔIIC +20 assembly result and the per-product test statements in the kit.
Cork underlayment works under most floating floors, and many owners use it exactly that way. Pairing it with a cork floating floor adds a second acoustic layer and the highest tested results.
Yes. The kit includes our GreenGuard Gold, ECO Institut, and CE certificates, and the cover letter references them directly.
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