How to Choose Wood Wool Acoustic Panels: Fibre, Fire and Acoustics Explained

June 15, 2026

Wood wool acoustic panels (fibrolite) look simple, but a few choices decide whether your room ends up quiet and good looking or just expensive. Here is what actually matters when you specify them.

1. Which fibre width should I choose?

This is the most visible choice. Sonablock comes in three fibre widths:

1.0 mm fine gives the densest, cleanest surface. Best for corporate offices, healthcare and hospitality where a precise look is wanted.
1.5 mm medium is the versatile middle ground and the most popular for mixed commercial use.
2.0 mm coarse is open and tactile, suited to loft offices, gyms and retail where a raw aesthetic is intentional.

2. What build-up behind the panel gives the best acoustics?

This is the choice most often got wrong, because people compare panel numbers without comparing constructions. An absorption figure is only meaningful alongside what sits behind the board.

Sonablock reaches αw 0.60 to 0.65, Absorption Class C, tested to EN ISO 354 by RISE Research Institutes of Sweden (report O100282), as a bare panel with a 200 mm air gap. Mounted tight against a hard wall with no cavity it performs noticeably worse, particularly in the low mid frequencies. Add mineral wool into the cavity and absorption rises substantially: this is true of all wood wool cement board, and published test data across the category shows Class A build-ups achieved that way. If you see a headline figure quoted as "up to 1.00" from any manufacturer, that refers to a composite build-up rather than a bare board.

Practical guidance: choose 25 mm boards for the best performance, or 15 mm where ceiling depth is tight, leave as deep a cavity as the ceiling void allows, and talk to us about adding mineral wool if the specification calls for a higher absorption class.

3. What fire rating do I need?

For commercial walls and ceilings you usually need a reaction-to-fire class on file. Standard Sonablock is Euroclass B-s1,d0 to EN 13501-1: low fire contribution, low smoke, no flaming droplets, valid with and without an air gap. Where a project mandates non-combustible, the Sonablock FireSafe series is classified A2-s1,d0 in accordance with EN 13168:2012+A1:2015, available across all formats and thicknesses. FireSafe is not listed online yet, so request it through the contact form. Always confirm the spec your project requires.

4. What colours and finishes are available?

Natural, white RAL 9010, light grey RAL 7035, dark grey RAL 7004 or black RAL 9011, with custom RAL and NCS on request. The surface needs no filling, sanding or painting after install, which saves time on site.

5. How do I work out order quantity and edge profile?

Wood wool is sold by the pallet (30.96 m² for 25 mm). Below a pallet a surcharge applies, so plan coverage with a small waste allowance. Edge profiles (square, bevelled and others) change how panels meet, so pick the edge before you order.

Need help matching a spec to your project? Browse the Sonablock range or contact us for a project quote. Sonablock is made in Latvia by Stiga RM, PEFC certified and CE marked, and is a sustainable alternative to Heraklith and Troldtekt.