by Paul Guarnera
(Arizona United States)
If you are building a new ceiling in a room where soundproofing ceilings is a concern, or are looking to solve problems of sound control, use this section in conjunction with Sound-proofing Walls. As the house diagram on indicates, intervening in just part of the structure of the room you want to make quieter will probably have little effect. Sound passes through ceilings from above and through ceilings under floors from below.
Impact noise on a floor above is most common, hard heels on a bare wood floor being the worst offender. For sound proofing purposes. regard a room that has living spaces both above and below as having two ceilings. one that it sits on. one above. The principles of soundproofing a ceiling are the same as those of soundproofing a wall, but the number of possible interventions is more limited because the structure of a. ceiling and floor above does not permit doubling the barrier to sound (as in building a double wall with dead air space between the two parts). or building with staggered studs (because the joists that hold up the roof or second story cannot be staggered). The most effective way to soundproof a ceiling is to insert insulation and hang the ceiling surface from Z channels, metal strips that hold wallboard away from an old ceiling surface, or bare joists. the same way resilient channels hold wallboard away from a wall. The channels are easy to install.
Soundproofing ceilings is best done before the ceiling is finished. With finished ceilings, you may choose to install a new surface over the old. sandwiching insulation between the two, or to rip down the old ceiling and build a new one, perhaps with a double skin. Impact noises can be treated without touching the ceiling at all by padding and carpeting the floor above.
QUIETING ABOVE THE CEILING I The most effective combination of materials for deadening sound from a floor is a layer of 1/2-inch insulating board nailed to the floor, followed by a layer of hardboard glued to the insulating board and this in turn topped by a layer of rubber underlayment glued to the hardboard and then wall-to-wall carpeting laid on top of that.