ROCKWOOL Multirock is a light-density water repellent slab for partition walls , ceilings and pitched roofs. Multirock is generally used for excellent  thermal insula­tion and acoustics purposes  in partition walls , attics and pitced roofs where it can be installed as an additional layer below rafters on the in­ner side of the room.  Like all ROCKWOOL products it protects against fire; provides acoustic comfort due to its fibrous structure; is uniquely durable against all forms of weather and is only sourced from sustainable materials.