Sealing out the sound with Inter-tenancy Wall System Substitution

R2.2 Intertenancy Construction - Christchurch

Summary

The Christchurch multi-dwelling project was specified with the GIB® Barrier system which incorporated an 11kg acoustic insulation infill. This system is designed to meet NZBC acoustic requirements and improving the thermal and acoustic perfomance of multi-dwelling properties. Earthwool® Glasswool R2.2 11 kg/m² wall insulation was used as the infill insulation, meeting the GIB Barrier system specifications without compromising on any aspect of the performance.

What was the challenge?

Under the New Zealand Building Code, a Sound Transmission Class (STC) for walls, floors and ceilings of no less than 55 is required for building elements between occupancies in household units.

To meet these requirements, project managers, DC Living, have specified the GIB® Barrier system for the internal walls of the multi-unit townhouse project. Featuring double stud framing, 13mm plasterboard on each side, and 11kg/m³ density acoustic insulation, the system achieves a 56-68 STC.

Seeking to maximise the overall comfort and indoor health of the building, in addition to meeting thermal and acoustic requirements, the project manager has requested a substitution for the specified R2.2 wall insulation infill.

Learn more about R2.2 Wall Insulation for Multi-dwelling construction

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Knauf Insulation's Inter-Tenancy Wall Insulation Solution

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What was the solution?

Knauf Insulation proposed that the Earthwool® Glasswool R2.2 Wall insulation be substituted into the wall system. This product substitution is supported by a statement of equivalence from Marshall Day Acoustics, confirming that an insulation infill material of the same density and thickness may be used in the system without affecting acoustic performance.

Further technical support from Winstone Wallboards – the manufacturer of the GIB® system –confirmed that the GIB® system’s warranty and fire performance would not be impacted by the substitution.

At 90mm thickness, the R2.2 Wall insulation is designed to fit snuggly between the studs and dwangs, offering a smooth friction fit installation and delivering exceptional acoustic performance.

Marshall Day’s statement of equivalence paves the way for the Earthwool® Glasswool 11kg/m³ R2.2 Wall insulation to be an accepted solution for GIB® inter-tenancy wall system. This will afford specifiers, installers, and homeowners the opportunity to take advantage of Earthwool® Glasswool’s unique benefits without compromising on performance.

To complete the acoustic envelope, Earthwool Glasswool R3.6 Ceiling insulation was installed in the midfloor, while the R2.8 Wall insulation was selected for the external walls.

Why Earthwool glasswool

Earthwool® glasswool products are made using ECOSE® Technology, a sustainable, plant-based binder with no added formaldehyde, acrylics, dyes, or colours. This manufacturing process reduces the carbon footprint while maintaining excellent product performance.

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What was the result?

Substituting the Earthwool® Glasswool wall product allowed the inter-tenancy wall system to achieve the required acoustic and thermal performance without impacting the integrity of the system. It also allowed the project manager to take advantage of Earthwool® Glasswool’s range of unique benefits that will deliver positive outcomes for occupants throughout the life of the building.