A question came across my desk today asking if you can retrofit RSIC-1 over an existing ceiling? The simple answer is no, you can not achieve the desired acoustical results when the RSIC-1 is installed directly under an existing ceiling. You can physically install the RSIC-1 Retro under an existing ceiling, but with substantially handicapped results. Below is a ceiling that has the RSIC-1 installed under an existing ceiling. This creates what’s called a triple leaf ceiling. These types of ceilings typically have not performed well acoustically.
The Correct way to build an acoustical ceiling with minimal impact to the bottom line is to tear off the existing gypsum board, add insulation if needed, and install a new ceiling using the RSIC-1 clips. This has shown to increase the acoustical performance of ceilings by up to 15 IIC points. That means you ceiling will transmit 70% less noise. I have attached an image below, for a reference. The difference can seem daunting, but the increased cavity above the gypsum board helps the RSIC isolator increase performance.