There seems to be two kinds of 2 story houses available to build in Perth. The first uses double brick for both floors and a suspended slab in between. These are very expensive per square metre compared with a typical single floor home. The other kind are more affordable but use "master wall" panelling. This 75mm thick material supposedly has good insulation and sound deadening properties. However i have my doubts coming from double brick. Has anyone had experience with this kind of walling?