Studio Build

Isolating a floor/ceiling – a real case

One of the first steps in our studio build is working out how to treat the floor of the office, which is directly above the studio. The floor is yellow tongue and clip down flooring on 90mm steel channel.

The options are;

1. Put insulation under the floor and plasterboard on the underside of the steel channel. Then hang isolators and put two layers of plasterboard and Green Glue with some more insulation above it (System 1 below), or;

2. 
   Add plasterboard directly under the existing yellow tongue with Green Glue and then do the same as before - hang isolators and put two layers of plasterboard and Green Glue with the same total combined insulation above it System 2 below).

Which system will give us the best isolation?

Existing floor from underneath

System 1

OR

System 2

Calculated transmission loss of floor/ceiling system.

Calculated transmission loss

Pink – System 1

Brown – System 2

System 2 is clearly the better choice because of the big increase in low frequency transmission loss. Mid and high frequency isolation of over 80dB is plenty so it's a good choice to sacrifice some mid/high frequency isolation for more at low frequency.

Interestingly, the cavity resonances are clearly visible, with system 1 at about 35 and 75Hz and system 2 at about 25Hz.