What Is Wood Wool Cement Board (Fibrolite)? A Plain Guide for 2026
Wood wool cement board, known in Latvia and much of Europe as fibrolīts (fibrolite), is one of the oldest and most dependable acoustic materials still specified today. If you have ever looked up at a softly textured ceiling in a school, a sports hall or a studio and wondered what it was, there is a good chance you were looking at wood wool.
What it is made of
The recipe is refreshingly simple: long strands of spruce wood wool, Portland cement and water. Nothing else. The timber is shredded into fine fibres, coated in cement and pressed into rigid boards. There is no glue, no added formaldehyde and no plastic binder, which is why the material is so often chosen for schools, healthcare and public buildings where indoor air quality matters.
Why people still specify it
Three properties keep fibrolite relevant decades after it was first made:
- Acoustics. The open fibre surface absorbs sound rather than reflecting it. Our Sonablock panels reach a sound absorption coefficient of αw 0.60 to 0.65 with a 200 mm air gap, which is Absorption Class C and enough to noticeably calm echo in a hard room.
- Fire. Because the wood is locked inside cement, the board carries a Euroclass B-s1,d0 rating to EN 13501-1, meaning low contribution to fire, low smoke and no flaming droplets.
- Durability and climate. Cement does not mind moisture, so the panels tolerate up to 90 percent relative humidity and do not warp in cold or damp rooms.
How it looks
Fibrolite has an honest, tactile surface. The fibre width sets the character: a fine 1.0 mm fibre reads clean and precise, while a coarse 2.0 mm fibre gives a bold, raw texture. It can be left natural or finished in white, grey or black, and it needs no filling, sanding or painting after install.
Is fibrolite the same as asbestos sheet?
No, and this is worth clearing up. In some English-speaking markets the word "fibrolite" was historically a brand of asbestos cement sheet. Modern wood wool cement board contains no asbestos at all. It is wood, cement and water, and it is fully REACH compliant with an Environmental Product Declaration.
Where to use it
Offices, restaurants, classrooms, gyms, studios and any space where noise control and a natural, durable finish both matter. It works on walls and ceilings, with or without an air gap behind it.
Our Sonablock range is wood wool cement board made in Latvia by Stiga RM, PEFC certified and CE marked, and is a sustainable alternative to Heraklith and Troldtekt panels. See the full Sonablock range.