The Siderise AVC Acoustic Void Closure is a high‑performance laminated composite acoustic seal in sheet form (1.24 m × 2.04 m × 30 mm).

It consists of an outer resilient foam layer and an inner flexible mass barrier membrane.

Engineered for easy compression fitting into apertures, gaps, and irregular voids, it provides a durable, airtight seal that greatly reduces sound transmission across boundaries.

Designed for construction and building acoustic applications, this void closure helps maintain acoustic integrity by preventing sound flanking via ceiling plenums or overhead voids.

With an acoustic rating of 27 dB Rw (to BS EN ISO 140‑3:1995) and fire classification B‑s1, d0 (EN 13501‑1), it meets stringent performance and safety criteria.

This product is ideal for sealing small or irregular cavities typically found at junctions between partition walls and overhead structures (floor slabs, roof decks).

Supplied in full sheets for on-site cutting, it offers flexibility and adaptability to site conditions.

Specification:

Thickness: 30mm

Width: 1240mm

Length: 2040mm

Dimensions: 2.04m (W) x 1.24m (L) x 30mm (T)

Reaction to Fire: B‑s1, d0 (EN 13501‑1)

Surface weight: 12 kg/m²

Acoustic performance: 27 dB Rw (BS EN ISO 140‑3:1995)

Composition: Resilient foam + flexible mass barrier membrane

Installation: Compression fit, friction fit, or secured with metal angles (top & bottom)

Siderise AVC Acoustic Void Closure Features and Benefits:

 · Composite construction: Resilient foam + mass barrier membrane for superior acoustic performance

 · Easy compression fit: Quick installation into gaps, apertures, and voids

 · Effective noise control: Achieves 27 dB Rw reduction in accordance with BS EN ISO 140‑3:1995

 · Fire rated: Classification B‑s1, d0 to EN 13501‑1

 · Surface weight: 12 kg/m²

 · Accommodates irregularities: Conforms to uneven soffits or non‑linear surfaces

 · Prevents sound flanking: Seals acoustic bypass via ceiling plenums or voids

 · Versatile: Suitable for both new build and refurbishment projects

 · On‑site adaptability: Cut to shape from full sheet format

Siderise AVC Void Closure Applications:

 · Sealing junctions between partition walls and overhead slabs or roof decks

 · Filling small or irregular voids and cavities in ceiling voids or plenums

 · Acoustic upgrades or refurbishments in residential, commercial, institutional, or industrial buildings

 · Maintaining continuity of acoustic barriers in suspended ceilings, service voids, and perimeter gaps

 · Preventing sound flanking through hidden voids above ceilings or below floors

Siderise AVC Void Closure Installation Guide:

 · Site assessment & gap measurement:

Measure the width, height, and depth of the gap, aperture, or void to be sealed.

Account for any uneven surfaces or irregularities.

 · Cut to shape:

Using a sharp utility knife or fine-toothed saw, cut the sheet to the required dimensions, allowing slight oversize for compression fit.

Ensure straight edges and clean cuts for better sealing.

 · Dry fit (compression fit / friction fit):

Push the closure strip into the gap, compressing it slightly to create a snug friction fit.

The resilient foam should deform slightly to accommodate irregularities.

For small gaps or narrow voids, friction fit alone is often sufficient.

 · Secure for larger gaps:

Where the void is large, or the closure cannot be held by friction alone, install metal angle sections (top and bottom) to retain the closure panel.

Fix the metal angles to the substrate and press the closure into place, ensuring full contact and compression.

 · Seal edges (if necessary):

Any residual small gaps or edges can be sealed with acoustic sealant to maintain airtightness and acoustic performance.

Use a compatible, fire-rated acoustic sealant recommended by Siderise.

 · Inspection & quality check:

Verify that the closure is uniformly compressed and in full contact along its edges.

Check for visible gaps or voids and fill them as needed.

Confirm that the installation maintains continuity of acoustic barriers across the junction.

*Further information may be found in our Downloads section.

Fairly easy access to all PDF files.

Datasheet ǀ Declaration of Performance - DoP ǀ BBA Certificate ǀ Installation Guide ǀ Certificates ǀ Brochure ǀ SPEC Sheet