Looking under the dis-assembleable section of the structure you can see a high performing wall type common in multi-residential developments. This partly finished wall is known as a discontinuous wall, and features two frames which have been installed approximately 20mm apart, making them completely independent of each other. This complete separation eliminates the direct transfer of vibration from one wall panel to the other, and when combined with the two layers of fire rated plaster board required to reach a 90/90/90 FRL, achieves an acoustic rating higher than all other cost competitive wall types for a similar depth. Indeed, when completed, the half-finished system here has been proven to provide an Rw+Ctr or airborne acoustic rating of 54.

While the section of wall shown here isn’t load bearing, it is important to note that discontinuous walls can be loadbearing, with floor cassettes bearing directly on to them. Where this is the case and 90mm timber studs are used, evidence suggests that timber party walls can perform more efficiently than is commonly seen in concrete post and slab designs, with wall thicknesses typically measuring up to 50mm thinner. While this may not seem like a lot a face value, a typical multi-residential project may feature hundreds of meters of party wall, and therefore this thinner panel may add tens of square meters in extra saleable area, and hundreds of thousands of dollars worth of extra revenue.

Note that where there are discontinuous party walls located above each other on consecutive floors it is important that there is a cavity barrier installed between floors to mitigate the spread of fire between sole occupancy units. While this is difficult to show in a full-scale model, if you look closely you can see a strip of high-density non-combustible insulation which has been inserted between floor cassettes, blocking the vertical spread of fire.