Insulation is key to ‘outstanding’ in BREEAM

Duncan Voice of Construction Materials Online (CMO) explains:

This year’s BREEAM New Construction 2018 manual update has seen changes to the ways in which insulation in buildings is assessed. Insulation now plays a significant role and could be the deciding factor in achieving an ‘outstanding’ or ‘excellent’ grading for your building.

Credit ‘HEA 05 Acoustic performance’ is worth three credits in a BREEAM assessment and is becoming more important for house building. With the aim of creating acoustically comfortable spaces for people, there are three strands that need to be addressed to achieve the three credits available within this category:

  • Sound insulation;
    • Indoor ambient noise level; and
    • Room acoustics.

The importance of acoustic insulation
Acoustic insulation is important to ensure the acoustic performance of walls, floors and ceilings. High-performance acoustic insulation allows designers to create lightweight and thinner build-ups while still achieving the required performance.

To achieve the first credit, different standards must be adhered to depending on the building type – office, residential, educational, healthcare, etc. Though these values may differ, the principle is always the same: reduce airborne and impact sound transmission. Airborne is more important for walls, impact for floors.

How to reduce sound transfer
1. Add acoustically absorbent materials that absorb the energy of soundwaves so those that make it to our ears are considerably less intense.
2. Increase material density. The greater the mass of the wall, the harder it is for sound to pass through.
3. Introduce clear cavities so there is no structural path for sound to transfer directly through the wall from one side to the other.

Air gaps aside, acoustic insulation is a key player in reducing sound transfer between spaces. Mineral rock wool, a highly absorbent material, is an ideal choice for this purpose. As sound tries to pass through the air trapped within the fibrous structure, it gets absorbed by friction. In addition, the random orientation of these fibres makes it very difficult for sound to find a path from one side to the other. Mineral rock wool is also relatively dense as far as insulation goes, increasing the mass of the build-up.

While the update offers new guidance, one factor remains certain, the choice of insulation materials is crucial in achieving a desired BREEAM rating. For more information about choosing insulation for your project, contact Insulation Superstore on 01752 692 206 or visit