Resilmat RMI
Resilmat RMI is a resilient sill-plate isolation strip supplied as a roll — it decouples top and bottom plates from the surrounding structure, interrupting structure-borne vibration between rooms and floors. RMI installs fast, resists moisture and mold, and field-cuts to length for a clean, continuous isolation gasket under wood or light-gauge steel plates on slab, subfloor, or framing.
- Structure-Borne Break: Continuous resilient strip under top/bottom plates interrupts rigid contact — reducing flanking paths so less vibration travels between rooms and floors.
- Fast, Low-Profile Install: Stocked in the 3-1/4" plate width at a thin 5 mm thickness, in 15 ft and 30 ft rolls — roll out, trim with a knife, done. No special tools.
- Durable and Versatile: Works with wood or light-gauge steel plates on slab, subfloor, or framing. Stays resilient under load and accommodates minor surface irregularities.
- Cost-Effective Upgrade: Adds substantial isolation for pennies per linear foot — delivering acoustic gains with virtually zero build-up. Ideal for new construction and retrofits.
RMI Specifications
- Roll width
- 3-1/4"
- Thickness
- 5 mm
- Roll length
- 15 ft or 30 ft
- Bearing pressure range
- 1–50 PSI
- Substrates
- Wood or light-gauge steel plates on slab, subfloor, or framing
- Resistance
- Moisture and mold resistant
Resilmat W20R isolators
- Width (outside diameter)
- 1 3/8 in
- Height (thickness)
- 3/8 in
- Center bore
- 1/4 in
- Max spacing
- 16" – 24" on center along sill
RMI Project Calculator
Enter your surface square footage. We'll return a clip, channel, and screw count for your project — calculations run on our servers so estimates stay accurate as our field data improves.
Adds MLV over Good for a denser limp-mass layer.
Estimate mat footage from the room's wall area — RMI runs continuously under both top and bottom plates, so we double the wall length and add 10% for cuts, corners, and joins. W20R washers land at every plate fastener (16"–24" o.c.). We stock RMI in one size — 5 mm thick × 3-1/4" wide — in 15 ft and 30 ft rolls, and the calculator recommends the cheapest combination of the two that covers your footage.
STC Gauge
Compare how the RMI performs across assembly tiers. Select an assembly below to see the resulting STC score.
RMI plate isolation + clips + channel system + MLV + double 5/8" drywall with Green Glue, insulated stud wall.
- STC 30-39: Loud speech clearly audible next room.
- STC 40-49: Loud speech muffled — normal residential wall.
- STC 50-59: Loud speech barely audible; suitable for offices & multi-family.
- STC 60+: Approaches studio-grade isolation.
How RMI compares
| Model | Primary Use | Format | Coverage | Isolation Element |
|---|---|---|---|---|
| RMIthis | Continuous plate isolation (top and bottom sills) | Roll stock, field-cut | 15 ft or 30 ft per roll | Resilient elastomer strip (5 mm, 3-1/4" wide) |
| W20R | Point isolators along sill plate | Discrete disc (16" – 24" o.c.) | Per-fastener | Elastomer washer |
| A237R | Resilient wall clip (field of wall) | Individual clip | ≤ 48" o.c. | Thermoplastic rubber sound cells |
Applicable Assemblies
See where the RMI fits — from budget baseline to studio-grade isolation.
Best — RMI + Clips + Insulation + MLV + Double Drywall + Green Glue
Slab / subfloor · RMI under top and bottom plates · stud wall · insulation · clips + channel system · MLV · 5/8" drywall · Green Glue · 5/8" drywall · acoustic sealant.
Better — RMI + Clips + Double Drywall + Green Glue
Slab / subfloor · RMI under top and bottom plates · stud wall · insulation · clips + channel system · 5/8" drywall · Green Glue · 5/8" drywall · acoustic sealant.
Good — RMI + Silent FX Drywall
Slab / subfloor · RMI under top and bottom plates · stud wall · insulation · Silent FX damped drywall · acoustic sealant.
