Architects and building system specifiers: I have spoken to two sound engineers recently, both told me they thought SIPs were poor for party wall construction so I thought it was time to share the facts.
Our SIP building system has been used successfully in party wall construction achieving a 59dB reduction in airborne sound transfer between dwellings.
The requirement for Building Regulations is a 45dB reduction so our SIP system far exceeds the requirements.
The test was based on construction with our thinnest panels (119mm SIP) with 25mm mineral wool in the service void and plasterboard plank to either side and 3mm plaster skim coat.
The overall thickness of the party wall construction is 416mm, (see illustration) with an un-insulated cavity this achieves a U-value of 0.12W/m²k and with an insulated cavity achieves a U-value of 0.10W/m²k. Lower U-values can be achieved by increasing the thickness of the SIP wall panels.