fix the ceilng?

my parents r fixing there house up and i wanted to ask when they remove their old ceiling and put on the plasterboard do they need to insulate the space between the upstair bedroom and the down stairs ceilng if yes is there any special thay should use?
scully3574, January 2010


done
Insulation is not necessarily required however, if you want to reduce sound then solid sound insulation would be a good idea

Mike, February 2010
DON'T insulate between the two,there is no benefit(unless it's a bungalow)and the upstairs will be realty cold.

Joiner, January 2010