Aotearoa / New Zealand

We've recently purchased a house that was built in 1982, as a Multi Dwelling Unit.

The plans show that the Intertenancy wall is built as a Firestop Wall, and is made of 200mm thick Masonry Blocks (Vibrapac), 50mm Strapping on top of the blocks, with Batts, and topped off with 9.5mm Gib (on both sides of the wall).

I was wondering what peoples experiences were with this type of wall from this era in terms of Noise Isolation? Concerned with not only sounds coming from the neighbors, but also sending any noise their way.

We are planning on adding an extra layer of 13mm Noiseline Gib once we move in.