Passive Design

Noise control in interior partitions

Interior noise can be controlled by sealing joints and incorporating sound-absorbing materials.

On this page:

• noise control in new partitions
• noise control in existing partitions
• noise control in ceilings
• noise control in timber floors.

In general, internal sound-reducing construction should have mass and sound-absorbent material. All joints should be sealed (to minimise air gaps through which sound might pass), and – as much as possible – the structure between the linings should be discontinued.

Options for sound-reducing construction for new internal partitions:

• A standard 100 mm x 50 mm timber partition with two layers of 9 mm plasterboard one side, sound absorbing insulation and one or two layers of plasterboard on the other side – good noise reduction.
• A staggered stud partition with 150 x 50 mm bottom and top plates, 100 x 50 mm off-set studs, sound-absorbing insulation woven around the studs and 12.5 mm plasterboard on both sides – moderate noise reduction.
• Double wall construction with two 100 x 50 mm partitions and a 10 mm gap, studs in each partition off-set from the other partition, sound-absorbing insulation between studs and two layers of 9 mm plasterboard both sides – excellent noise reduction.

Solid masonry construction provides an excellent acoustic barrier as well as providing thermal mass.

A key to acoustic design is ensuring that there are no gaps or paths in the completed construction through which noise can pass. This includes:

• avoiding service penetrations in the acoustic wall
• sealing around the perimeter of the wall.

Noise control in existing partitions

Options for improving sound transmission reduction to existing partitions:

• Adding an additional layer of 9 mm plasterboard on both sides of a standard timber partition.
• Removing the lining from one side of a standard timber partition, adding sound-absorbing insulation and two layers of 9 mm plasterboard on one side and another layer of 9 mm plasterboard on the other side.
• Building an additional partition beside a standard timber partition that has had the lining removed on the face adjacent to the new partition, adding sound-absorbing insulation, two layers of 9 mm plasterboard on the external face of the new partition and an additional layer of 9 mm plasterboard on the external face of the existing partition.

Noise control in ceilings

For both new and existing ceilings, improve sound transmission reduction by:

• adding an additional layer of 9 mm or 12.5 mm plasterboard
• removing existing lining and installing resilient batten fixings to existing battens, sound-absorbing insulation and two layers of 9 mm plasterboard.
• Removing open down-lights or other ceiling penetrations

Noise control in timber floors

Standard floor/ceiling construction with particle board or plywood flooring and a 9 mm plasterboard ceiling below has low resistance to impact noise (IIC32). Options for improving the resistance to impact noise include:

• a standard floor construction with sound absorbing insulation, a ceiling system with proprietary resilient batten fixings and steel battens and two layers of 9 mm plasterboard
• a standard floor/ceiling construction with carpet and rubber underlay
• a standard floor construction with carpet and rubber underlay, sound-absorbing insulation, a ceiling system with proprietary resilient batten fixings and steel battens, two layers of 9 mm plasterboard and carpet and rubber underlay.

Squeaking timber floors

Timber floors can generate noise by squeaking and transmitting sounds such as footsteps and scraping chairs. To avoid squeaking:

• the flooring should be glued as well as screw- fixed to the joists
• the framing must be dry (less that 24% MC) when the flooring is installed
• timber floor boards must be securely cramped and nailed.