Carpet tiles for lining box & volume

They have a solid bitumen type backing, so yes they'll reduce the volume an amount if used "everywhere". Not too sure on the carpet bits but they're dense twisted fibres, ISTR.

I s'pose rule of thumb would be treat it as a 3mm or 4mm reduction per unit area covered.

They should do something of a job of mass damping big open areas if glued in strongly enough.
 
They have a solid bitumen type backing, so yes they'll reduce the volume an amount if used "everywhere". Not too sure on the carpet bits but they're dense twisted fibres, ISTR.

I s'pose rule of thumb would be treat it as a 3mm or 4mm reduction per unit area covered.

They should do something of a job of mass damping big open areas if glued in strongly enough.

Thanks Jerms that answers that :)