What R3.1 acoustic batts actually do
Noise moves through a wall two ways, through the air in the cavity and through the building structure itself. A dense batt fills the cavity so there is no air path left for sound to travel along. That is why density does more of the work here than the R-value number does, and why R3.1 at 110 mm thick behaves differently to a thinner batt carrying a similar rating.
These go into internal walls, party walls between attached dwellings, and the space between floors in a double storey. Anywhere one room needs to stay quiet while the next one does not.
Getting the fit right
R3.1 comes in 430 mm and 580 mm widths, which suit the 450 mm and 600 mm stud and joist spacing used in most Australian timber framing. The batt should sit in the cavity under slight compression at the edges so it holds itself in place with no gaps at the top, the bottom or the sides.
Gaps are what undo an acoustic install. A batt cut short at the top of a wall leaves an air path, and that one gap will carry more sound than the rest of the wall stops. Where the framing is non standard, or where services run through the cavity, the batts need cutting to fit rather than forcing.
Thermal performance as well
The R3.1 rating is a thermal one, so these batts slow heat transfer at the same time as they cut noise. On an internal wall that matters more than people expect. A bedroom or home office backing onto an uninsulated garage holds its temperature far better with a dense batt in the wall. For external walls, see the wall insulation range, and for upper floors see between floor insulation.
Supply and install across Melbourne
Climate Control has supplied and installed insulation in Melbourne homes since 1965. Buy R3.1 online for delivery, or collect free from the Nunawading factory. If you are working out quantities for a whole house or a townhouse project, call 13 12 24 and we will go through the take off with you.
Before you order it is worth reading the five most common acoustic insulation mistakes we see on Melbourne jobs.